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The Federal Highway Administration (FHWA) is conducting an interlaboratory study to validate certain findings in the Strategic Highway Research Program (SHRP) C-343 report on alkali-silica reactivity. This paper reports the Virginia Transportation Research Council (VTRC) findings relative to the rapid immersion test (AASHTO TP 14). Tests were conducted examining the use of AASHTO TP 14 for evaluating the effectiveness of fly ash and to determine the necessary dosage of lithium hydroxide monohydrate (LiOH H₂O) to prevent excessive expansion resulting from alkali-silica reactivity (ASR). The results obtained are encouraging with respect to the use of the TP 14 test to evaluate the effectiveness of a particular fly ash with a particular aggregate; however, it does not appear to be suitable for determining (LiOH H₂O) dosage rates. A summary report incorporating the results of all participating laboratories will be issued by the FHWA..

Encouraged by the performance of high performance normal weight composite girders, the Virginia Department of Transportation has sought to exploit the use of high performance lightweight composite concrete (HPLWC) girders to achieve economies brought about by the reduction of dead loads in bridges. Transfer length measurements (conducted on two AASHTO Type IV HPLWC prestressed girders) indicated an average transfer length of 17 inches, well below the AASHTO and ACI requirements. Two HPLWC AASHTO Type II girders and a 48 x 8 inch normal weight 4000-psi concrete deck were fabricated. The girders were cast of concretes with a compressive strength of 6380 psi and a unit weight of 114 pcf. Full scale testing of the girders was conducted to evaluate development length and flexural strength in HPLWC composite girders. Embedment lengths of five, six, and eight feet were evaluated. Tests indicated a development length of about 72 inches, marginally below the ACI and AASHTO requirements. All tested girders exceeded their theoretical flexural capacity by 24% to 30%. A third composite Type II girder was cast of high performance normal weight concrete and topped with a 48 x 8 inch normal weight 4000-psi concrete deck. This girder was intended as a control specimen. Prestress losses in the HPLWC AASHTO Type IV girders monitored over a nine-month period were found to be less than those calculated using the ACI and PCI models.

A two-lane continuously reinforced concrete pavement was built in Blacksburg, Virginia, as a part of Virginia's Smart Road. One of the lanes is 12 ft wide, and the other is 14 ft wide. The additional 2 ft was part of the shoulder. Below the concrete pavement is a 3-in-thick open-graded drainage layer (OGDL); one section is asphalt stabilized, and the other section is cement stabilized. The concrete pavement was cured by a curing compound except that the 12-ft lane was also covered with plastic and straw because of concerns with cold ambient temperature. The objective of this project was to determine the material properties of the concrete, instrument the pavement, monitor construction practices, and monitor the performance of the pavement over 4 years. The concrete had high early strength, low permeability, and high shrinkage. The average crack spacing was more than 3 ft, indicating satisfactory performance. In general, cracks were wider when they were further apart, but the differences in crack spacing and width were variable and small in some cases and could not be correlated after 4 years. The end sections had less cracking than the interior sections of the pavement. There were fewer cracks and more space between cracks in the 12-ft lane and fewer cracks in the pavement over the asphalt-stabilized OGDL. This was attributed to a better cure in the 12-ft lane and to a lower friction over the asphalt-stabilized base. No changes to the specifications were recommended as a result of the study findings.

This study was conceived as the first phase of a three-phase program to develop a safety data base for intracity bus transit. It involved reviewing the state of the art of general transportation safety management, examining the current intracity bus safety records systems of the federal, state, and local governments and the transit industry, and developing the basis for an intracity bus safety records system for the Commonwealth of Virginia. Definitions of motor bus traffic accidents, passenger accidents, and crime were developed data elements and codes were selected; and an accident/incident report form was designed. Guidelines for developing data files, coding, entry, editing, and data processing procedures were developed along with recommendations on the development of the last two phases of the program.

This study evaluated latex-modified concretes (LMC) and concretes containing silica fume (SFC) or Pyrament-blended cement (PBCC) in bridge deck overlays in the field. The condition of the overlays was monitored for 4 years. LMC and SFC were placed in 2 days using a vibratory roller screed spanning half the width of the bridge, each side in 1 day. PBCC was placed in small segments, each covering half the width of the bridge, in 2 months. The placement in small segments was dictated by traffic control requirements. PBCC was used with no admixtures. Similarly, LMC was used with no admixture except the latex-modifier. The results indicate that LMC, SFC, and PBCC have low permeability and satisfactory strengths. PBCC develops high very early strengths within hours, even in cold weather, and SFC develops sufficient compressive strength for opening to traffic in 1 day. Since all three concretes are prone to plastic shrinkage, proper and immediate curing are essential.

VDOT's current policy is to use and accept from others the 1994 Highway Capacity Manual (HCM) as the basis for capacity analysis on Virginia's streets and highways. VDOT uses the latest version of the Highway Capacity Software (HCS). Software programs replicating the 1994 HCM may be used by others submitting work to VDOT for review; however, all input data and assumptions must be provided, and VDOT may use the HCS to check the submitted analysis. The analysis may be rejected if different results are obtained. To recommend appropriate revisions to this policy, this study evaluated computer software other than HCS that can be used in the analysis of signalized intersections, determining which programs provide acceptable results. The study then evaluated the results from simulation models to determine when and how to use this output in the analysis of signalized intersections. The study recommended that, in addition to HCS, VDOT use and accept from others SIGNAL94 and HCM/Cinema, or TRAF/NETSIM for capacity analysis at isolated intersections. CINCH, however, should not be used or accepted. For congested, oversaturated intersections, TRAF/NETSIM should be the preferred analysis type. Estimates of queue length at isolated signalized intersections should be derived from SIGNAL94, HCM/Cinema, or TRAF/NETSIM. For non-isolated intersections where queuing and spillback are a potential problem, simulation analysis with TRAF/NETSIM should be used instead of capacity analysis to determine the operational characteristics of the corridor.

VTrans2035, Virginia's statewide multimodal transportation plan, requires 25-year forecasts of socioeconomic and travel activity. Between 2010 and 2035, daily vehicle miles traveled (DVMT) will increase between 35% and 45%, accompanied by increases in population (28% to 36%), real household income (50%), employment (49%), transit trips (75%), and enplanements (104%). Of the 2.27 to 2.87 million additional Virginians forecast by 2035, most (1.72 to 2.34 million) will settle in one of four planning district commissions (PDCs). These PDCs, and their expected population increases, are George Washington Regional (0.25 to 0.28 million), Richmond Regional (0.33 to 0.41 million), Hampton Roads (0.31 to 0.41 million), and Northern Virginia (0.83 to 1.23 million). Virginia will likely see the number of people age 65 and over double from 1 million at present to 2 million in 2035. Four potential policy responses to these forecasts are given in this report: (1) encourage increased density at select urban locations to reduce CO2 emissions; (2) use cost-effectiveness as a criterion to select project-level alternatives for achieving a particular goal; (3) identify policy initiatives to serve increased demographic market segments, and (4) quantify the economic harm of general aviation airport closures. These policy responses are not the only ones feasible but were selected because they necessitate the interagency coordination that is the premise of VTrans2035. The first two policy responses demonstrate limited but real promise. The first may reduce DVMT by 1.1% to 6.4% of the baseline 2035 DVMT forecast, for a reduction of 1.507 million metric tons of CO2 annually. Yet DVMT is affected to a greater degree by factors over which decision makers exert less influence than with density. For example, the 2035 baseline DVMT decreases by 7% if an alternative population forecast is assumed; 10% to 65% if real household income remains relatively flat; and 49% to 82% if fuel costs increase to

The purpose of this study was to identify the currently available nondestructive evaluation technology that holds the greatest potential to detect moisture in flexible pavements and then apply the technology in multiple locations throughout Virginia. Ground-penetrating radar (GPR) was chosen for use in a field investigation because of its ability to measure large areal extents and reports of successful implementation by other researchers. This technology was used to determine the moisture content of the subgrade beneath five flexible pavement sections in Virginia. The GPR survey was conducted at normal driving speeds, and data were collected at a sampling rate of 1 scan per foot. For each site, three scans were collected in the travel lane (in the right wheel path, the center of the lane, and in the left wheel path). Existing passing lanes were also scanned. Initial data processing subdivided each pavement section into a three-layer system composed of the hot-mix asphalt layers, the aggregate base layers, and the subgrade. The processing also included calculating the dielectric constant of each layer. These raw data were used to conduct further analyses considering data from only the subgrade. The data were normalized to highlight those areas with the highest dielectric constants since it is known that moisture will have the greatest influence on the dielectric properties of the material. This study showed that GPR can identify areas of varying dielectric constant attributed to variations in the moisture content of the subgrade of various pavement sections. The use of the GPR offered a safe and rapid means for nondestructively surveying large areas of pavement as the survey was conducted at normal driving speeds. In addition, the use of a statistically based data normalization procedure allowed GPR to be used to assess qualitatively the moisture condition of the subgrade of flexible pavements. Two advantages of GPR testing are that it can be used to provide a contin

101937, The Virginia Department of Transportation (VDOT) collects millions of gallons of runoff at its nearly 300 salt storage, facilities each year, with some portion of this water being reused for the generation of salt brine. Storing this collected stormwater, runoff in tanks rather than ponds affords some advantages in that less water is collected; the water that is collected remains, cleaner; and the water is more likely to be properly managed and disposed of when necessary., The purpose of this study was to quantify the monetary benefits of using underground storage tanks for the temporary, storage of salt-laden runoff generated at VDOT’s salt storage facilities. This was done by way of a simple cost analysis, comparing the use of underground storage tanks to the open-pond systems more commonly used now. Information on the costs, related to the purchase, construction, maintenance, and operation of both storage types was used to develop a simple cost, estimation tool, i.e., a benefit/cost spreadsheet. The tool was structured so that modifications could be made based on sitespecific, information on precipitation, water disposal costs, brine usage, etc., The study concluded that although the purchase price of underground storage tanks is substantially higher than that of, ponds, the 50-year all-inclusive cost of tanks is similar to the cost of ponds for stormwater storage. Although the costs are highly, variable and dependent on site-specific conditions, when the medium default values used in the benefit/cost spreadsheet are used, tanks are slightly cheaper than pond relining or new pond construction. As disposal costs increase above current values, storage, by way of tanks will become an increasingly better option., Based on this information, the study recommends that VDOT’s Environmental Division collaborate with the Capital, Outlay Section of VDOT’s Administrative Services Division, residency administrators, and area headquarters superintendents to, evaluate the option of using underground storage tanks for the storage of stormwater runoff from salt loading pads at locations, that are replacing (relining) existing ponds or at facilities where new pond construction is being considered.

A video image detection system (VIDS) is an advanced wide-area traffic monitoring system, that processes input from a video camera. The Autoscope VIDS coupled with an information, management system was selected as the monitoring device because testing had shown it to, be the most advanced system available with respect to performance, reliability, and accuracy., The purpose of this project was to evaluate the capabilities of the VIDS. The primary, objective was to assess the performance of the VIDS for incident detection, and a secondary, objective was to examine its capability to monitor traffic. Existing hardware was to be used for, the VIDS as much as possible in order to fit the VIDS into the existing TMS Center operations, and to minimize additional costs., Based on an evaluation that focused on traffic monitoring, the VIDS performed unsatisfactorily, at two sites and satisfactorily at a third site. The location of the video camera relative, to the monitoring site, which is critical to effective operations of the VIDS, was the major cause, of the unsatisfactory performance. The primary objective was not achieved. The potential for, using the Autoscope at existing camera locations in Northern Virginia is limited. Based on the, performance of the Autoscope at the Woodrow Wilson Bridge, it was concluded that it is difficult, to accurately return an Autoscope camera to its monitoring position after it is moved for surveillance., A dedicated camera is necessary for the VIDS., Recommendations were made for the use of the VIDS and for project planning and contract, administration for future projects of this nature.

Areas where anthropogenic development coincides with aquatic systems often impede the flow of organisms and nutrients in either an upstream, downstream, or bidirectional path. These impediments are especially outstanding in the tidal and nontidal freshwater areas of Virginia where diadromous fishes are hindered from moving upstream onto spawning grounds and the upstream ecosystems lose out on the contribution of marine derived nutrients. Recent removals of major impediments such as Embry Dam Fredericksburg, Virginia, opens large expanses of previously blocked spawning habitat for recreationally and commercially important diadromous species. Many smaller river systems require different methods of impediment rehabilitation and various fish passage systems are being used throughout the country to assist in the reconnection of previously impeded stream segments. The primary intent of this research was to assess different fish passage systems as they relate to impediments created by road culverts and to design and install systems in Virginia. Road culverts are common throughout the state and represent one of the important types of potential barriers to upstream migration. We examined the available literature (mostly from Pacific Northwest river systems), explored extant impediment databases (created by VDGIF and VCU) for the Rappahannock River drainage, monitored the effectiveness of the two major fish passage types being used in Maryland (pool-weir designs and Alaskan steep pass design), consulted state and federal officials, chose sites for Virginia stream implementation of fish passage and had fabricated the appropriate passage structures. It was concluded that site selections can be prioritized, if fish passage is a primary concern, by use of databases that describe anadromous fish use in the appropriate watershed. Models of spawning and nursery habitat preferences help in site selection by allowing quantification of habitat to be opened by the installation of fish p

This research investigated, through experimental and analytical studies, the complex interactions that take place between the structural components of an integral bridge and the adjoining soil. The ability of piles and abutments to withstand thermally induced cyclic loads was investigated by conducting large-scale cyclic load tests. Three pile types and three integral abutments with hinges were tested in the laboratory. Experiments simulated 75 years of bridge life. Numerical analyses were conducted to analyze the interactions among the abutment, the approach fill, the foundation soil, and the foundation piles. The results indicated that H-piles are most suitable for supporting integral abutments. Concrete piles and pipe piles were too stiff in response to repeated lateral loads, resulting in tension cracks at the connection with the abutment. Further, a hinge in the integral abutment effectively reduces pile stresses by absorbing some of the rotational movement.

Following the recommendation of the Virginia Transportation Research Council's Pavement Research Advisory Committee, this project was initiated to determine the effectiveness of including subsurface drainage systems in pavements in Virginia. The researchers sought to determine the effectiveness of these systems by conducting a literature review and by comparing the strengths of pavement sections with and without a subsurface drainage layer in a limited field investigation involving two pavement structures in Virginia. The strength of the pavement structure was analyzed using the falling weight deflectometer. The researchers concluded that the drainage layer appears to affect positively the in-situ subgrade resilient modulus and the in-situ structure number. Further, inclusion of a properly constructed drainage layer does not adversely affect the deflection of a pavement and thus does not introduce a weakness into the pavement structure. However, the condition of the outlet pipes appears to be of high importance. The researchers recommend that tests with additional sites be conducted in the spring when the subgrade moisture is expected to be highest; that the Virginia Department of Transportation (VDOT) develop a maintenance program to maintain functioning drainage outlet pipes; and that VDOT continue the practice of constructing subsurface drainage features on high-priority pavements. In 2005, VDOT anticipates spending approximately $45 million on resurfacing interstate and primary roadways. According to the literature review, the average service life of flexible pavements (time between successive rehabilitation efforts) is approximately 9 years. Including subsurface drainage features offers a 4-year extension of service life (a 44% extension). Thus it can be approximated that the current practice of including subsurface drainage features is saving VDOT approximately $20 million per year. However, the amount of this cost savings may not be fully realized if drainage

The Virginia General Assembly's House Budget Bill for the 2006-2008 biennium directed the Virginia Department of Rail and Public Transportation (DRPT) to update the status of a proposed passenger rail service, called the TransDominion Express (TDX), between Bristol, Richmond, and Washington, DC. Although TDX has been studied five times prior to this report during the past 10 years, ridership estimates have varied substantially, from as small as 26,000 to as large as 500,000. Findings from this study are that the capital cost for infrastructure to support full service between Bristol, Richmond, and Washington, DC, is estimated at approximately $206 million (in 2010 dollars). The annual operating cost for full service is estimated at $19 million (in 2010 dollars), presuming two round-trip visits to all stations. The annual ridership is estimated at 14,000 to 58,000. Based on the estimated ridership levels, annual revenue is projected to be between $0.4 million and $1.8 million in 2010 dollars. Based on the estimated annual operating cost of $19 million, an annual subsidy of between $17.2 million and $18.6 million will be required. However, estimated ridership varies by station location: e.g., it is estimated that 70% of TDX ridership would occur at stations between Lynchburg and Alexandria inclusive. Although each additional station might add riders, some stations would add more riders than others. These findings are tempered by the fact that any travel demand forecasts for TDX rely on 18 assumptions that are documented in Table 9 of this report. For example, this report assumes that a schedule identified in 2001 as feasible will remain feasible as two external circumstances affecting the feasibility of TDX evolve: the Heartland Corridor Double-Stack Initiative and the I-81 Rail Corridor Study, both of which may improve or adversely affect passenger operations. Other assumptions pertaining to the sensitivity of passenger travel demand to other factors, such as food se

This study addressed the evaluation of alternative test methods to identify the presence of polymer modifiers in performance-graded binders for the purpose of quality assurance. A method of identification is presented in AASHTO T302, Polymer Content of Polymer-Modified Emulsions and Asphalt Binders, that uses Fourier transform infrared (FTIR) spectroscopy to evaluate the constituent elements in binders or emulsions. With proper calibration, output from FTIR can be used to determine the presence and approximate content of polymers in an asphalt binder. AASHTO T301, Elastic Recovery Test of Bituminous Materials by Means of a Ductilometer, offers an alternative method to determine the presence of polymer by evaluating the elasticity of the binder. Samples of binder were collected from contractor tanks and tested in accordance with AASHTO T301 and AASHTO T302. The performance grade was verified in accordance with AASHTO M320. Test results were evaluated to identify calibration needs, test variability, and choice of preferred methodologies for adoption into the quality assurance program. Results of the study identified the use of either FTIR analysis or elastic recovery as a timesaving alternative to full-fledged performance grading in the initial investigation of concerns about the presence of polymer. Both methods identified binders containing varying polymer contents with no instances of false positive identification. However, based on the results of this study, neither method is suitable to determine binder grade. The investigator recommends that the elastic recovery and FTIR analysis be incorporated as quality assurance tests to verify the presence of polymer in mixtures that specify the use of polymer-modified asphalt binders. Following this, the frequency of quality assurance sampling of polymer modified binders should be increased to ensure that inferior material is not being used in premium mixtures. Further, AASHTO T301 should be adopted in place of Virginia Te

Highway Safety Program Standard 5, Driver Licensing, issued by the U. S. Department of Transportation requires, in part, that the states test applicants for a renewal of their operator's license on rules of the road at least once every 4 years. The state of Virginia requested a waiver of the knowledge testing portion of the standard until evidence could be presented to show that it had the desired safety benefit. The Virginia Highway and Transportation Research Council and the Virginia Division of Motor Vehicles conducted an experimental evaluation of several alternative approaches to implementation of the standard. This evaluation randomly assigned members of the renewal population of drivers to four study groups: (1) a control group receiving no treatment; (2) a group that received only a driver's manual; (3) a group that received a manual and a test to be taken at home; and (4) a group that received a manual and were requested to take a test in the DMV examining station at the time of application for license renewal. The subsequent driving performance of members of the four groups was monitored and data for accidents, major convictions, minor convictions, accidents with associated convictions, and administrative actions taken under provisions of the Driver Improvement Program were tabulated at 6-, 12-, 18-, and 24-month intervals. For the two groups administered a knowledge test, comparisons were made of the performance of those who had passed, failed, or refused to take the test. Of the few statistically significant differences found between the study groups, none would suggest the practicality of knowledge testing as an effective highway safety countermeasure. A large number of the differences observed involved the group who had refused to take the test at home. Other than for the minor conviction entries for this group, there were no comparisons which showed differences across all four time periods. The results obtained at the end of the four study time period

This report describes the investigation of structural failure in a section of the Appomattox Bypass along U.S. 460 in the town of Appomattox, Virginia. The bypass is a four-lane divided highway. The section that was investigated is an 11-year-old section of jointed plain concrete pavement located approximately between mile post 8.10 and mile post 8.35 in the eastbound lane. A forensic investigation was conducted to identify the causes of failure and determine reasonable remedial measures. The investigation included a visual condition survey, non-destructive testing, coring through pavement layers, and slab removal. Drainage problems, construction issues, and other pavement component issues were found with regard to this rigid pavement and led to the failure. Water trapped within the open-graded drainage layer aggravated the failure rate of the drainage layer abrading the underlying soil cement layer. As a remedial measure, the researchers suggested that the drainage function be restored and the damaged pavement layers be repaired.

00021555, Four bridge decks were overlayed and patched and one bridge pier was patched using concrete with and without corrosion inhibiting admixtures. Some concrete surfaces received topically applied corrosion-inhibiting treatments prior to placement of the concrete. The repairs were successfully completed, and the initial condition of the repairs is good. Corrosion probes were installed in many of the repairs, and measurements are being made each quarter to determine macrocell current, macrocell potential, and resistance. The probe indicates that corrosion is occurring in repairs done with and without corrosion-inhibiting treatments. No conclusions can be drawn at this time, and the study will continue for a total of 5 years.

Ramp metering is an effective, viable, and practical strategy used to manage freeway traffic. It is a proven freeway management technique as various forms of ramp control have been in place since the 1960s in the Chicago, Detroit, and Los Angeles areas. Due in part to the success of these early applications, ramp metering has received increased emphasis in recent years under the umbrella of advanced traffic management systems (ATMS), a component of intelligent transportation systems (ITS). ITS America reports that there are currently more than 40 ATMS deployed, under construction, or in the planning stage in the U.S. by state transportation agencies. The future of ramp metering is also in this ITS context. Integration and interface with local street system control and other advanced ITS traffic control systems such as advanced vehicle control systems, dynamic route guidance, and advanced traveler information systems are the latest in ramp metering applications. Ramp meters are in place and working effectively on segments of I-395 and I-66 in Northern Virginia. The Virginia Department of Transportation is very much interested in the feasibility of implementing ramp metering on other segments of freeways throughout the state. Accordingly, the purpose of this study was to review and synthesize the existing literature on ramp metering. Specific topics included in the review were: impacts of ramp metering, including its advantages/benefits and disadvantages/disbenefits, warrants, criteria, and guidelines for ramp metering, metering rates. Detailed information on these topics is included in the report as well as general conclusions regarding ramp metering.

The service life of Virginia's concrete bridge decks is generally controlled by chloride-induced corrosion of the reinforcing steel as a result of the application of winter maintenance deicing salts. A chloride corrosion model accounting for the variable input parameters using Monte Carlo resampling was developed. The model was validated using condition surveys from 10 Virginia bridge decks built with bare steel. The influence of changes in the construction specifications of w/c = 0.47 and 0.45 and w/cm = 0.45 and a cover depth increase from 2 to 2.75 inches was determined. Decks built under the specification of w/cm = 0.45 (using slag or fly ash) and a 2.75 inch cover depth have a maintenance free service life of greater than 100 years, regardless of the type of reinforcing steel. Galvanized, MMFX-2, and stainless steel, in order of increasing reliability of a service life of greater than 100 years, will provide a redundant corrosion protection system. Life cycle cost analyses were conducted for polymer concrete and portland cement based overlays as maintenance activities. The most economical alternative is dependent on individual structure conditions. The study developed a model and computer software that can be used to determine the time to first repair and rehabilitation of individual bridge decks taking into account the time for corrosion initiation, time from initiation to cracking, and time for corrosion damage to propagate to a state requiring repair.

The Virginia Department of Transportation (VDOT) is faced with trying to maintain its roads with materials whose cost is increasing at an alarming rate. The significant cost increase for asphalt concrete, which is used to pave a majority of Virginia's roads, is primarily linked to the cost increase for the petroleum products from which asphalt binder is produced. In the 1990s, VDOT developed a special provision to allow contractors, upon request, to use waste shingles in asphalt concrete. These shingles contain approximately 20 percent asphalt, which replaces part of the expensive virgin binder in the mix. In 2006, a contractor requested that the manufactured waste shingles be allowed on an overlay paving project in southeast Virginia. The 4.1-mile two-lane section was paved using a surface mix containing 5 percent shingle waste and a surface mix containing 10 percent recycled asphalt pavement for comparison. Density tests were performed on the pavement, and various laboratory tests such as permeability, fatigue, tensile strength ratio, rut, and binder recoveries were performed on samples of mix collected during the construction of the section. Both the field and laboratory test results indicate that the behavior and performance of the two mixes should be similar. The study recommends that VDOT's Materials Division prepare a permanent special provision to allow the manufactured waste to be used in asphalt. Because of the success of using manufactured waste, tear-off shingle waste resulting from replacing home shingles should also be investigated. Although manufactured waste shingles are available only in the northeastern part of North Carolina, several Virginia counties near the North Carolina border may be able to realize a cost reduction if shingles are used in the future. There is potential for approximately 50,000 tons of hot-mix plant mix containing waste shingles to be supplied to VDOT's Hampton Roads District per year. It was estimated that as much as $2.69 c

Corrosion inhibitor admixtures (CIA) and galvanized reinforcing steel (GS) are used for the corrosion protection for reinforced concrete bridges. The results of a 3.5-year evaluation of exposure specimens containing CIA from three different manufacturers and GS are presented. The specimens were built to simulate four exposure conditions typical for concrete bridges located in the coastal region or inland where deicing salts are used. The exposure conditions were Horizontal, Vertical, Tidal, and Immersed Zones. The specimens were kept inside the laboratory and were exposed to weekly ponding cycles of 6% sodium chloride solution by weight. The methods used to assess the condition of the specimens included chloride concentration measurements, corrosion potentials, and corrosion rates. Additionally, visual observations were performed for identification of rust stains and cracking on concrete surfaces. The results of chloride testing indicate that the amount of chlorides present at the bar level is more than sufficient to initiate corrosion. Chloride and rapid permeability data indicate no significant difference either in a rate of chloride ingress or in the diffusion coefficients for concretes with and without CIA. Corrosion potentials were the most negative for the Bare Steel (BS) specimen prepared with the Armatec 2000 corrosion inhibitor and generally indicated a 90% probability of active corrosion. Corrosion potentials were similar for the two BS control specimens and the BS specimen prepared with Rheocrete 222 and generally indicated an uncertain probability of corrosion. Corrosion potentials were the least negative for the BS specimen prepared with DCI-S corrosion inhibitor and generally indicated a 90% probability of no corrosion. Rate of corrosion measurements were the highest for the BS control specimens and the one prepared with A2000 and the most recent data suggest corrosion damage in 2 to 10 years. Although early rate of corrosion measurements were higher o

Offsite airport facilities provide ground transportation, baggage and passenger check in, and other transportation services to departing air passengers from a remote location. The purpose of this study was to develop models to determine the airports that might be candidates for such a facility and estimate the percentage of travelers that would choose to use one to access the airport. Offsite airport facility operations were examined in New York, Los Angeles, Zurich, London, and Hong Kong, and passenger data were obtained from surveys distributed at six U.S. airports. A total of 1,700 air-traveler questionnaires were completed at four airports without offsite facilities, i.e., Baltimore/Washington International Thurgood Marshall Airport (BWI), Charlottesville-Albemarle Airport (CHO), Norfolk International Airport (ORF), and Richmond International Airport (RIC), and at two airports with offsite facilities that provide ground transportation only, i.e., Boston Logan International Airport (BOS) and San Francisco International Airport (SFO). The survey results show that 68% of passengers who traveled directly to the airport terminal would consider using an offsite airport facility if available. Of the passengers who currently use an offsite airport facility that provides only ground transportation, almost 70% indicated that their access would be improved by expanded services including baggage and passenger check in. The two main reasons cited for using the offsite airport facilities surveyed in this study were reduced travel time variability (43%) and lower cost (39%). With the data collected at the six airports, two models were developed sequentially to determine the demand for offsite facilities. The airport access quality model was used to establish initial demand by assuming that the likelihood of a viable offsite facility is directly proportional to the difficulty, or resistance, encountered during the current access trip to the airport. This model yielded expected

Aluminum bridge decks may prove to be an alternative to concrete decks for improving the performance of structural bridge systems. Combining excellent corrosion resistance with extremely low density, aluminum decks can prolong surface life, facilitate the construction process, and expand rehabilitation capabilities. Reynolds Metals Company (Reynolds) has invested considerable resources to develop a proprietary aluminum deck system. The Virginia Department of Transportation agreed to employ the Reynolds' deck system in two projects. Using Federal Highway Administration sponsorship, the Virginia Transportation Research Council initiated a study to evaluate the aluminum deck system. The first phase of this project analyzed the static response of a 2.74 m x 3.66 m (9 ft x 12 ft) deck panel. Both service-load and ultimate-load tests were performed on the panel at the Turner-Fairbank Structural Laboratory in the fall of 1996. The experimental and analytical evaluation of the ultimate load static tests is the subject of this report. The failure load and failure mechanism were predicted with great accuracy. The model data predicted panel failure at a load of 911.89 kN (205 kips) by yielding under the load patch, whereas failure during the laboratory test occurred at a load of 872.07 kN (196.05 kips) by gross yielding underneath the load patch.

Hydraulic cement concrete overlays are usually placed on bridges to reduce the infiltration of water and chloride ions and to improve skid resistance, ride quality, and surface appearance. Constructed in accordance with prescription specifications, some overlays have performed well for more than 30 years whereas others have cracked and delaminated before the overlay was opened to traffic. Shrinkage of the concrete is the most common cause of cracking in overlays. The use of Type K (expansive) cement should increase the probability that concrete overlays with minimal cracks will be constructed. This report describes the Virginia Department of Transportation's first experience with the use of Type K cement for the construction of a latex-modified concrete overlay. One lane of the overlay was constructed with traditional Type I/II cement, and the other lane with Type K cement. With the exception of the cement, the requirements for the overlays were the same. The evaluation of the overlays included measurements for slump, temperature, air content, compressive strength, permeability to chloride ion, shrinkage, and bond strength. As expected, the shrinkage of the concrete containing Type K cement was much less than that of the concrete containing Type I/II cement. Other properties were similar. The use of Type K cement is estimated to increase the cost of the concrete approximately 2.6 percent, or about $1/yd² for an overlay 1.5 in thick. This is much less than the cost to seal the shrinkage cracks in an overlay: $10/yd². Greater savings can also come from the longer service life of a crack-free overlay. To gain more experience, the Virginia Department of Transportation should construct additional latex-modified concrete overlays using Type K cement.

Final report for phase two of an analysis of the impediments to spawning migrations of anadromous fish in Virginia rivers.

107898, Climate change introduces infrastructure flooding challenges, especially for coastal regions with low topographic relief. More frequently occurring intense storms and sea level rise are two projected impacts of climate change that will lead to increased flooding risks. These changing conditions make having the ability to forecast accurately potential flooding impacts to transportation infrastructure critical. The Virginia Department of Transportation (VDOT) Hampton Roads District worked with Hassan Water Resources, PLC, a consulting firm, to create a flood forecasting model called the Regional River Severe Storm (R2S2) model for, among other purposes, flood warning applications. The model was built for watersheds within the district that cover approximately 2,230 square miles and include 493 bridges and culverts., This report describes work by researchers at the University of Virginia to complete computational enhancements to the R2S2 model so that it might ultimately be implemented by VDOT for flood forecasting applications. Specific project tasks were to (1) design, implement, and test software for automating rainfall forecast inputs from the National Weather Service; (2) speed up the model execution using a graphics processing unit (GPU); and (3) automate the visualization of model output through an online, map-based system and automate emails of flood impacted locations to decision makers within VDOT., Task 1 resulted in software for automating the access, download, and transform of rainfall forecast data produced by the National Weather Service High-Resolution Rapid Refresh (HRRR) model into the inputs required by the R2S2 model. The heart of the R2S2 model, and the most time-consuming part of the model, is a high-resolution hydrodynamic model called the Two-dimensional Unsteady Flow (TUFLOW) model. Task 2 resulted in speeding up the TUFLOW model by 50x from over 100 hr when the model is run using a central processing unit to just over 2 hr when using a GPU. Finally, Task 3 resulted in software for automating tasks including extracting maximum water depth from the model output for a set of bridges, creating a Google Maps–based website showing impacted bridges, and having the system notify decision makers via email of bridges at risk of being overtopped., The study recommends that VDOT’s Hampton Roads District Hydraulics Engineer undertake the following: (1) with the help of research staff at the Virginia Transportation Research Council, coordinate with the University of Virginia research team to begin using the R2S2 model to determine the accuracy of the output derived using the new GPU-based TUFLOW solver and begin the calibration process using real rainfall data and streamflow information; and (2) based on the information gathered, determine what additional R2S2 model modifications are required to make the model a fully automated flood forecasting system. These modifications could include automating the data exchange between HEC-HMS and TUFLOW and making further enhancements to the workflow for visualization and notification of model results based on feedback from potential VDOT users.

This report presents the regional conformity analysis and recommendation for a finding of conformity for the Hampton Roads 2030 Long Range Transportation Plan (LRTP, or "Plan") and associated Fiscal Year (FY) 2009-2012 Transportation Improvement Program (TIP, or "Program"), both as amended by the Hampton Roads Transportation Planning Organization (HRTPO). The HRTPO serves as the designated Metropolitan Planning Organization or MPO for the Hampton Roads region1. This analysis was conducted in compliance with the federal transportation conformity rule (40 CFR Parts 51 and 93) and the corresponding state conformity regulation (9 VAC 5-151).

Animal-vehicle collisions (AVCs) have a growing impact in the United States in terms of safety, economic loss, and species conservation. According to estimates from insurance claims, Virginia has consistently ranked as one of the top seven states for deer-vehicle collisions (DVCs) since 2002. Of the state's estimated 43,500 to 47,700 DVCs in 2006, less than 14% were reported to the police and stored in the Virginia Department of Transportation's (VDOT) accident database. Virginia has no standardized method of sufficiently tracking AVC occurrences and locations, creating difficulty in researching and implementing mitigation efforts to reduce accidents. Valuable AVC data can be obtained from documenting the instances and locations of animal carcasses from the roadway, but most transportation organizations do not systematically record these removals. This project entailed testing a personal data assistant (PDA) enabled with a global positioning system (GPS) receiver for the collection and analyses of animal carcass removals (CRs) from the roadway. Using GPS-enabled PDAs and software developed by Western Transportation Institute, maintenance personnel from a VDOT area headquarters in Rockbridge County collected 8 months of spatially accurate CR data. Rockbridge County DVC estimates derived from the CR data collected for this study were more than 9 times greater than the number of AVCs reported in police records. These spatial data can be easily used for density analyses to determine "hotspots" of AVCs. Implementing mitigation at these areas can ultimately lead to fewer AVCs and associated reductions of human deaths, injuries, and financial losses; improved traffic operations; a reduction in maintenance costs related to carcass removal and disposal; and wildlife conservation. VDOT is currently undergoing changes to its method of documenting roadway maintenance activities, including the deployment of GPS-enabled PDAs to all area headquarters. These PDAs provide a mechanis

1459-030, This report presents the results of research to evaluate the potential of utilizing mitigated wetlands as stormwater Best Management Practices (BMPs). Results of wetland monitoring, wetland modeling, and geographic information system (GIS) development are presented. Average removal rates as high as 90% for total suspended solids (TSS), 65% for chemical oxygen demand (COD), 70% for total phosphorus (TP) and orthophosphate (OP), and 50% for zinc (Zn) were observed at study sites. Despite having stormwater runoff as a primary water source, the monitored sites supported apparently healthy and diverse vegetation, and a variety of wildlife. A mathematical model of transport of a pollutant in dissolved and particulate forms in a two segment, two-state system was developed. The model includes settling, diffusion, adsorption to plant and substrate, and vegetative uptake mechanisms. A GIS was developed to improve management of existing mitigated wetlands and to aid in siting of future mitigation sites. A link between a watershed model and this GIS is also described. The report concludes that mitigated wetlands may be as effective as conventional BMPs at improving the quality and at controlling the quantity of highway storm runoff.

Construction of created wetlands to mitigate for highway impacts requires more than $100,000 per ha of impacts. A detailed study of soil, hydrology, and vegetation at 10 recently constructed non-tidal mitigation sites indicates excessive soil compaction and a lack of organic matter continue to limit mitigation success. Detailed hydrologic studies at two mitigation sites (Charles City and Sandy Bottom) point out significant differences in their hydrologic regime vs. adjacent natural wetlands related to soil reconstruction procedures. Results from two compost amendment experiments at Charles City indicate that approximately 100 Mg/ha of organic amendment is optimal for reconstructing hydric soil conditions when natural organic enriched soil materials cannot be returned. Overall mitigation success would improve from (1) utilization of appropriate organic amendments, (2) tillage/ripping protocols at all sites to meet target density specifications, and (3) reconstruction of a soil-geologic profile that is similar in texture and permeability to natural wetland soils. These reconstruction guidelines will help ensure that VDOT complies with existing mitigation regulations in the most cost-effective manner.

87216, Concretes containing various supplementary cementitious materials (SCMs) such as silica fume, fly ash, and slag have improved properties. Nanomaterials (a nanometer, nm, is 10-9 m), new SCMs with possible applications in concrete, have the smallest particle size that is less than 100 nm. Nanomaterials are very reactive because of the particles' small size and large surface area and have great potential in improving concrete properties such as compressive strength and permeability. This study evaluated the use of a variety of nanomaterials in concrete compared with conventional concrete and concrete containing common SCMs. The potential benefits of using nanomaterials over other SCMs are their high reactivity; the need for smaller amounts, resulting in less cement replacement; and cost-effectiveness. Concretes containing nanosilica and nanoclay were prepared in the laboratory and compared to concretes containing silica fume, fly ash, slag, or only portland cement. Specimens were tested for compressive strength and permeability. The microstructure of selected concretes with improved compressive strength and permeability were analyzed using an atomic force microscope and nanoindenter to determine the reason for the improvements. The microstructure of the nanosilica concrete was denser and more uniform than that of the conventional concrete microstructure. In addition, the nanosilica had the largest improvement in both compressive strength and permeability among the nanomaterials tested. The results of this study indicate that some of the nanomaterials tested have potential in concrete applications. However, further evaluation is required before nanomaterials can be used in concrete. Specifically, they should be evaluated for improved dispersion to achieve uniformity, optimized amounts of ingredients, and cost-effectiveness.

The steady growth of commercial truck travel has led to an increasing demand for truck parking spaces at public rest areas and private truck stops on interstate highways in Virginia. This study developed a methodology to determine the supply and demand for commercial truck parking along these corridors. Supply was defined as the number of parking spaces available for commercial truck parking, and demand was defined as the sum of the parking accumulation and illegal parking at a given time. Phase I of this study developed a methodology to determine the supply and demand for commercial truck parking using I-81 in Virginia as a case study. This Phase II study expanded the study to other interstate highways in Virginia, checked the applicability of the parking demand model developed in Phase I, and developed new models when necessary. Extensive data on the characteristics of commercial truck parking and the characteristics of each truck stop and rest area were collected. In addition, truck drivers and truck stop owners/operators were surveyed. The data collected were used to develop models to describe the relationship between parking accumulation and independent variables such as traffic volume on the highway, truck percentage, parking duration, and the distance from a highway to a truck stop. After the applicability of the models was tested, they were used to estimate commercial truck parking demand in 2010 and 2020. Deficiencies of parking spaces with respect to estimated demand were then determined for each truck stop and the entire Virginia interstate highway system. The results indicate that the demand for commercial truck parking at individual truck stops on I-95 exceeds the supply by 10 to 22 percent and that there is no commercial parking shortfall at truck stops along I-64, 1-77, and I-85. However, there are shortfalls at rest areas on I-66, I-77, I-85, and I-95, varying from about 6 percent on I-85 to about 32 percent on I-95. If no new parking spaces are prov

Public interest in measures to make walking a safer form of personal conveyance manifests itself every several years in Virginia's General Assembly. Since 1981, the Virginia Transportation Research Council has conducted at least six studies regarding pedestrian safety, and two dealt specifically with legal issues. None of them, however, led to changes to the Code of Virginia (the Code). This study of pedestrian legislation and traffic safety was undertaken at the request of the Commissioner of Virginia's Department of Motor Vehicles in response to concerns expressed to him by state and local government officials. The authors reviewed the relevant literature, analyzed Virginia's pedestrian crash data, examined and critiqued Virginia's Code and those of other states with regard to pedestrian issues, reviewed the Uniform Vehicle Code, and surveyed the departments of education of all states to ascertain their efforts with regard to pedestrian safety education. The study showed that a significant number of pedestrians continue to be killed and injured in Virginia and that many of these cases can be related to specific vehicle and pedestrian actions as well as the age of the victim. Annually, 10 to 12 percent of motor vehicle crash fatalities are pedestrians, an average of about 105 per year. Theanalysis of the Code revealed that particular sections are either confusing or ambiguous concerning the actions required by or prohibited to motorists, pedestrians, or both. The survey revealed that Virginia was doing about as well as other states in educating its public schoolchildren concerning pedestrian safety. The authors recommend that Virginia revise its crash report form, modify and add to the pedestrian statutes in the Code, and institute public education and enforcement campaigns to address pedestrian safety issues. A separate document details the recommended additions and deletions to the Code in legislative format and is available upon request from the authors.

In 1994 the Virginia Department of Transportation (VDOT) developed a specification for the acceptance of asphalt concrete based largely on Marshall compacted volumetric properties of the mix. A copy of the Special Provision is shown in the Appendix. The development of this specification is consistent with national efforts such as AASHTO and the SHRP asphalt program, emphasizing volumetric properties as being more related to performance than gradation results. A pilot project was placed on 1-95 in the Fredericksburg District by Virginia Paving Co. in June 1994. Over a 3 week period, approximately 24,000 tons of mix were placed in accordance with the Special Provision. This report summarizes the results relative to acceptance and compares results obtained from the contractor, from the VDOT Elko Materials laboratory, and from several VDOT district materials laboratories.

A speed post-processor refers to equations or lookup tables that can determine vehicle speeds on a particular roadway link using only the limited information available in a long-range planning model. An estimated link speed is usually based on volume, the percentage of heavy trucks, the free flow speed on the link, and the facility type (e.g., interstate, two-lane highway). These post-processed speeds are used to estimate motor vehicle emissions in conjunction with the U.S. Environmental Protection Agency's MOBILE model. At least two post-processors in the form of software packages are available to VDOT staff. One, developed by Michael Baker Jr., Inc., can be used immediately with minor modifications as an interim measure to perform conformity analyses for new nonattainment areas. The other is being updated by VDOT's Northern Virginia District; a new generation is expected within a few months. Another option is for VDOT staff to code speed-volume equations directly into a spreadsheet, as has been done in the Appendix. The authors recommend that over the next 12 months, either the Research Council, VDOT, or the two organizations work together to validate the post processors available by comparing their computed and actual speeds on a variety of facility types. In conjunction with this effort and to the extent that resources allow, the effect of different input data, such as vehicle age, vehicle type, and travel speeds, on mobile source emissions as predicted by the MOBILE model should be studied.

The road history projects undertaken by the Virginia Transportation Research Council establish the feasibility of studies of early road networks and their use in the environmental review process. These projects, by gathering and publishing the early road orders of the vast parent counties, also lay the foundation for additional research by local groups over a broad area of Virginia. This volume marks the twenty-fourth entry in the Historic Roads of Virginia series, first initiated by the Virginia Transportation Research Council (then the Virginia Highway & Transportation Research Council) in 1973. Botetourt County Road Orders 1770-1778 expands the coverage of early western Virginia transportation records begun in the previously published Orange County Road Orders 1734-1749 and Augusta County Road Orders 1745-1769. This information will eliminate the need for further research into the Botetourt County road order records of 1770-1778. If questions arise about early roads once a VDOT road improvement project is already underway (or nearly underway), primary historical research of this nature can take 6 to 12 months to complete. Therefore, this study can be a source of potentially significant cost savings for VDOT, including the avoided costs of project delays and avoided consultant costs for cultural resource studies should questions arise.

Highway culverts may hinder the normal migrations of various trout species in wild trout streams, due to increased flow velocity, shallow water depths, increased turbulence, and perching. This can impede migrational movements, affecting the genetic diversity and long-term survival of some species. Often, the proper installation of culverts can reduce the adverse effects on fish while maintaining hydraulic efficiency. This study characterized the problems with existing culverts to develop guidelines for the future use of culverts in areas with high gradient streams. Installation criteria will ideally limit the use of bridges where culverts are appropriate, and eliminate the use of culverts where they would create fish passage problems. This will reduce installation, maintenance, and retrofitting costs. The study concluded that culverts can be considered the primary option for crossing trout streams if the following criteria are met: the culvert can be placed on the same slope as that of the streambed the slope of the stream is less than three percent the flow velocity does not exceed 1.2 meters/second under normal flow conditions the barrel of the culvert can be properly countersunk at the outlet to prevent perching. Bridges should be used at these crossings if any of the above criteria cannot be met. Also, baffles should not be used to control streamflow velocities in new culverts, and concrete aprons should not be used at culvert outlets. If culvert bottoms could be cast to have a roughness coefficient equal to that of the streambed, this would allow greater use of culverts at stream crossings without impeding the passage of trout.

103658, This study was designed to develop a novel approach for in situ evaluation of stress fields in the vicinity of fatigue-prone details on highway bridges using a low-cost microbolometer thermal imager., The method was adapted into a field-deployable instrument to obtain in situ visualization of the stress concentrations present at fatigue-prone details on highway bridges subject to random truck loading. The infrared thermoelastic stress analysis (IR-TSA) system developed in this study is available for use by Virginia Department of Transportation (VDOT) district structure and bridge personnel to evaluate fatigue-prone details on existing bridges., VDOT plans to implement the technology to validate repairs underway at the I-64 Delta Frame Bridge in Lexington and fatigue crack arrest repairs on other steel bridges in VDOT’s inventory. Guidance will be developed on the application and practical use of the technology for incorporation into VDOT’s Manual of the Structure and Bridge Division.

98483, The primary objective of this study was to evaluate the permanent deformation (rutting) and fatigue performance of, several thin asphalt concrete wearing courses using a scaled-down accelerated pavement testing device. The accelerated testing, was conducted using a model mobile load simulator (MMLS3). Field testing with the MMLS3 was conducted on a 4.75-mm, nominal maximum aggregate size dense-graded mixture installed at the Turner-Fairbank Highway Research Center. This, mixture (designated SM-4.75), two other conventional dense-graded mixtures, and a thin gap-graded mixture were also used to, prepare specimens for laboratory rutting tests using the MMLS3., Test results from more than 100,000 wheel load applications of the MMLS3 showed that the thin wearing courses, underwent various degrees of permanent deformation depending on their compacted air void content. According to the protocol, guidelines developed for the evaluation of permanent deformation and moisture damage when using the MMLS3, most of the, mixtures performed well. One exception was a coarser dense-graded material with a high amount of recycled asphalt pavement., No indication of fatigue cracking or other distress was observed for any mixture during or after testing., The study supports use of the SM-4.75 mixture on low- to medium-traffic roadways and for maintenance and/or, preservation applications. It further recommends that the Virginia Department of Transportation apply the methods demonstrated, through this research to assess better the stability of experimental wearing course mixtures in advance of wider spread field, applications.

In April of 1987, Congress passed the Surface Transportation and Uniform Relocation Assistance Act (STURAA), which permitted states to raise their maximum speed limit on rural interstate highways to 65 mph. Virginia's 65 mph speed limit went into effect on July 1, 1988, for passenger vehicles and on July 1, 1989, for commercial buses. This is the final report in a series to examine the 65 mph speed limit in Virginia, and it summarizes Virginia's experience with the 65 mph speed limit from 1989 through 1992. Following the implementation of the 65 mph speed limit, average and 85th percentile speeds increased on Virginia's rural interstates, and fatal crashes and fatalities increased significantly. On Virginia's urban interstates, on which the speed limit remained at 55 mph, there was a smaller increase in average and 85th percentile speeds, but there was a slight, nonsignificant decrease in fatal crashes and fatalities. Absolute numbers of fatal crashes and fatalities were used in this analysis rather than rates because traffic volume increases on interstates are averaged for both rural and urban systems. Thus, if volumes increased more on rural interstates, comparisons of relative rates would be misleading. The data in this report clearly show that speeds, fatal crashes, and fatalities increased on Virginia's rural interstates after the implementation of the 65 mph speed limit. However, these increases appear to have plateaued in the last two years of the study. Reports from other states and from national studies reflect a general increase in travel speeds and fatal crashes on rural interstates, but there is conflicting evidence on whether the 65 mph speed limit is the cause. Likewise, there is conflicting evidence concerning whether differential speed limits for trucks and cars have had an impact on the frequency of crashes in states maintaining such differential limits.

00021532-6940, Turning movement (TM) counts are used for a variety of intersection analyses, including traffic operations analyses, intersection design, and transportation planning applications. For many planning and design applications, especially in the case of, proposed future improvements to an intersection or even proposed new intersections, future year TM counts are needed for the, analysis. Accordingly, there is a need to forecast turning movements at the intersection., The purpose of the research was to inventory and review the methods used to forecast intersection turning movements., The effort was limited to a literature review and a limited survey of practitioners to determine methods currently being used to, make such forecasts., Based on this limited review, it was found that the state-of-the-practice for estimating turning movements is based on, using growth factors to project link volumes and TM counts. In many cases, engineering judgement is used to account for special, conditions or to accommodate known or anticipated land use changes that may significantly impact turning movements. The, implication, therefore, is that although there are similarities among methods used by a variety of organizations for a variety of, purposes, there is no identifiable preferred means of estimating turning movements. The most definitive technique found is the, procedures described in the National Cooperative Highway Research Project (NCHRP) Report 255.

The primary objective of this project was to test a full-scale prototype of a bridge deck design containing glass fiber reinforced polymer (GFRP) bars as the top mat of reinforcement. The test deck mimics the design of the deck of one span of the new bridge over Gills Creek on Rt. 668 in Franklin County, Virginia. The purpose of the tests was to verify the deck design and provide assurance that the deck will behave as expected. Aspects of the behavior of the bridge deck, such as failure load, failure mode, cracking load, crack widths, deflections, and internal stresses, were examined. Four tests were performed on the deck, all of which tested the deck in negative moment regions. The tests comprised two overhang tests, one test of the deck over an interior girder, and one test of a cantilever section of the composite deck and girder. The cantilever test modeled the deck in a continuous bridge over an interior support. From the tests, it was concluded that the design of the deck was quite conservative. The secondary objectives of this project were to comment on the construction of a bridge deck reinforced with GFRP bars, note the advantages and disadvantages, and critique the current state of the art of designing bridge decks with GFRP reinforcement. It was found that the advantages of construction with GFRP bars easily outweighed the disadvantages and that the placing of the top mat of GFRP bars was much easier than the placing of the bottom mat of steel bars. The state of the art for the design of bridge decks reinforced with GFRP bars was found to be generally conservative. Three primary criteria dictate the deck design: strength, allowable stresses in the GFRP bars, and crack widths. For this deck, the size and spacing of the transverse GFRP bars were governed by crack control criteria. In testing the deck, however, it was found that the measured crack widths were far smaller than the calculated widths. The measured bar stresses, after cracking, were below those c

The transportation programming process is undergoing a fundamental change akin to that which transpired with the advent of the Intermodal Surface Transportation Efficiency Act in 1991. Some stakeholders have expressed a desire that the programming process be transparent, and some have expressed an interest in using data-driven performance measures. Although there is widespread agreement concerning broad criteria, stakeholders may disagree over specific performance measures. Thus, transportation agencies have become interested in methods for selecting projects based on their merits rather than the more traditional approach of "first in first out." Accordingly, the Virginia Department of Transportation (VDOT) requested that the Virginia Transportation Research Council develop a template that VDOT could use to prioritize capital improvement projects. The role of the template is to help VDOT decide which project should be undertaken first. The scope of the template is limited to projects that are already being programmed. A template based on 14 of 75 performance measures examined was developed and applied to two projects. The template is oriented toward projects relating to the interstate and primary systems, but it is flexible enough that key policy choices can be made in its framework. These include controversial issues, such as access management and land use configurations, and more tedious but critical considerations, such as the relative importance of crash risk, infrastructure maintenance, economic development, and congestion relief. A promising benefit of the template is that it provides an opportunity to manage the debate as to the approach for deciding the order in which projects are programmed. The template will not eliminate disagreement, but it can foster discussion when parties have legitimate and differing opinions as to how projects should be prioritized. To that end, the template may be used as a discussion instrument between VDOT and some of its key sta

Traffic responsive plan selection (TRPS) control is considered an effective operational mode in traffic signal systems. Its efficiency stems from the fact that it can capture variations in traffic patterns and switch timing plans based on existing traffic conditions. Most of the research performed to date has focused on either small traffic networks-with up to five intersections-or theoretical networks. Past research has also focused on the threshold mechanism implemented in the National Electrical Manufacturers Association (NEMA) traffic controllers. There is very limited research on the pattern-matching mechanism implemented in the 170 controllers. This report documents a new approach to generating traffic scenarios for large networks, addressing issues such as the unequal traffic distribution and the large combination of traffic movements from multiple intersections. This approach is based on the selection of significant critical movements controlling the network using statistical correlation analysis of actual detector data and the use of synthetic origin-destination analysis of the entire network. The proposed approach was applied in the design of the traffic responsive control mode for the Reston Parkway arterial network, which has 14 intersections. Detector data were used to validate the results of the proposed approach. The validation process showed that the traffic system was correctly modeled and sufficiently represented by the proposed approach. Multi-objective optimization was used to generate the final timing plans and the TRPS pattern-matching parameters. Simulation analysis revealed that implementation of the traffic responsive control mode in the Reston Parkway network can achieve an average delay reduction of 27 percent and an average stops reduction of 14 percent on weekends and an average delay reduction of 18 percent and an average stops reduction of 21 percent on regular week days. The methodology documented in this report should be followed to

Rising energy costs and increased environmental awareness have brought attention to the potential benefits of warm asphalt in the United States. Warm-mix asphalt (WMA) is produced by incorporating additives into asphalt mixtures to allow production and placement of the mix when heated to temperatures well below the 300°F+ temperatures of conventional hot-mix asphalt (HMA). Potential benefits such as reduced plant emissions, workability at lower temperatures, extension of the paving season into colder weather, and reduced energy consumption at the plant may be realized with different applications. Trial installations of WMA, including two sections using the Sasobit WMA additive, have been investigated in Virginia. This study presents the results of laboratory testing to evaluate the performance of the mixtures used in the two Sasobit trial sections. The evaluation included comparisons of compactibility, volumetric properties, moisture susceptibility, rutting resistance, and fatigue performance between the HMA and WMA mixtures used in each section. Mixtures produced in the laboratory under conditions of varying temperatures and aging periods were tested, and the effects of temperature and aging were evaluated. The long-term performance of the two test sections was also modeled using the Mechanistic-Empirical Pavement Design Guide.Few differences were found between the HMA and WMA mixtures evaluated. The performance of WMA and HMA was similar when evaluated for moisture susceptibility, rutting potential, and fatigue resistance. The MEPDG-predicted distresses supported these conclusions; the predicted long-term performance of WMA and HMA was comparable. From these results, the recommendation was made that the Virginia Department of Transportation develop a special provision for the use of WMA. Despite its benefits, direct cost savings from the use of WMA are unlikely to be seen by VDOT. Currently, one concern with the use of WMA is the initial cost, which varies dependi

In late 2000, the Northern Virginia District of the Virginia Department of Transportation (VDOT) received a request from a visually impaired citizen to install accessible pedestrian signals (APS) at an intersection in Falls Church. Since there were no national or state guidelines for this type of installation, the district was asked to install APS at an intersection in a pilot effort and to develop appropriate guidelines that VDOT could use statewide for future installations. The Virginia Transportation Research Council was asked to assist in developing the guidelines. Further, a committee composed of representatives from VDOT, the Federal Highway Administration, the Virginia Department for the Blind and Visually Impaired, and the blind and visually impaired community (formal organizations and individual citizen activists) was established to provide overall guidance and advice. A Phase I report documented the initial efforts to develop the guidelines and described the following sections of the guidelines: (1) a procedure for requesting APS, (2) the basic requirements for retrofitting, (3) an intersection evaluation methodology, and (4) a funding process. In addition, the report recommended that the procedures in these four sections be piloted by using them to identify other appropriate intersections at which different types of APS equipment could be installed. This Phase II report describes the results of the pilot with regard to the first four sections of the guidelines and the development of the final two sections of the guidelines: the basic statewide specifications for APS equipment, and the installation procedures. The final guidelines for installing APS at an existing intersection are included in an appendix.