Search

This paper presents the results of the first driver behavior questionnaire (DBQ) study on analyzing Indian drivers’ aberrant behavior for red light violations (RLVs) at signalized junctions. An ordered probit model is developed using the drivers’ socio-demographic variables. The model results indicate that age has the strongest influence on drivers’ RLV behavior, followed by driving experience and level of education. The level of perceived RLV appears to increase with higher driving frequency and two-wheeler ownership. This research is also the first to analyze the aberrant behavior differences among male and female drivers concerning their demographics and driving experiences. It is unique to note that at a certain combination of various demographics (e.g., driving experience, education level, and daily trip frequency), the men and women are becoming equal in their aberrant behavior while committing RLVs. This finding is an interesting input for developing driver training and education programs. [ABSTRACT FROM AUTHOR]

Saturation flow rate (SFR) variations were analyzed using the video data collected at a signalized intersection in Winnipeg, Canada, to investigate the implications of adverse road-weather (RW) conditions for SFR distributions and characteristics. Survival analysis was implemented to develop stochastic SFR distribution functions considering censored data and a statistical analysis method was developed for determining the optimal critical vehicle (CV) for measurement of saturation headway. The analysis findings suggest that adverse RW conditions decrease SFR significantly and moves CV to the front of the queue while having little impact on SFR considering heavy vehicles. Furthermore, the findings imply that the conventional SFR estimation method overestimates the probability of saturation at a given flow rate. The proposed analysis method reveals stochastic characteristics of SFR and provides a method to estimate SFR distributions under different RW conditions, which is essential for improving the operation of signalized intersections, particularly in cold regions. [ABSTRACT FROM AUTHOR]

This study emphasized binder aging of bituminous mixtures in the field and compared it with newly developed field-simulating laboratory aging procedures. Monthly field cores from a pavement section were collected for this investigation over 2 years. After measuring the field core samples' bulk density, the air voids were calculated to assess the densification with time due to traffic. Binder was extracted from the field core samples, and further tests were carried out to assess the rate of aging with time. Also, the bituminous specimens prepared in the laboratory at the optimal binder content were subjected to field-simulating oven-aging methods. The bituminous mixture aging process in AASHTO R30 does not match field conditions in tropical countries. Therefore, new techniques have been developed in this study to calculate the number of days required for laboratory aging to simulate field-aging conditions. The oven was modified by introducing ultraviolet bulbs and oxygen supply, termed Laboratory Oven Aging-lll (LOA-III). Test results showed that 10 days of LOA-III corresponded to 47 months in the field. The Fraass breaking point indicated that LOA-III also simulates low-temperature conditions. Experiments conducted in the laboratory revealed that LOA-III accelerates aging and can simulate field conditions in tropical countries more accurately than AASHTO R30. The field study showed that higher initial air voids in the surface layer accelerate binder aging, causing raveling and surface cracking. Therefore, it is recommended to limit the initial air voids to 8% or less immediately after construction. Bitumen aging significantly influences pavement performance, leading to raveling and cracking when coupled with heavy traffic loads. Higher initial air voids, primarily due to insufficient compaction, accelerate binder aging. Binder aging can be minimized by restricting the initial air voids to 8% or less. If the initial air voids are decreased by 1%, pavement service life is increased by 10%. The procedure given in AASHTO R30 does not simulate field aging for tropical regions. Therefore, a field-simulating laboratory method was necessary. This study indicated that aging the mixture for 10 days by introducing UV rays and oxygen in the laboratory oven-aging (LOA-III) method simulates the pressure-aging vessel (PAV) and field aging accurately for tropical regions. The developed field-replicated laboratory aging procedure can be directly adopted to study binder aging on pavement sections in tropical climatic regions with similar pavement crust thickness and traffic. The duration of aging and other factors, like oxygen supply rate and UV light intensity, may need to be modified for pavements with varying thicknesses, traffic volumes, and climatic zones. [ABSTRACT FROM AUTHOR]