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• The study investigates the Safety-in-Number (SiN) effect on the perceived safety of bicycle riders. • In general, riders prefer routes with more bicycle traffic, which validates SiN. • In the presence of dedicated bicycle infrastructure, more bicycle traffic acts as crowding and demotivates the riders. • Riders prefer routes with a low volume of motorized traffic. • Routes with dedicated bicycle infrastructure have higher preference over routes with no infrastructure. Safety-in-Numbers (SiN) implies that the risk of collision per road user is less when there are more road users. Although the available literature has confirmed the existence of SiN as an objective measure of safety, the effect on perceived safety, especially in the context of bicycle riders, has received much less attention. This study investigates the SiN effect on the perceived safety of bicycle riders that influences route choice behavior. A stated preference survey was performed in the South Delhi district of Delhi. The effect of attributes like posted speed limit, the volume of motorized traffic, bicycle infrastructure, and bicycle traffic/ crowding on route choice behavior was investigated. A binary logit model was developed to quantify the effect of these attributes on route choice. The results indicate that, in general, riders prefer routes with more bicycle traffic, hence validating SiN. But the effect does not always hold. For some riders, in the presence of dedicated bicycle infrastructure, when the perceived safety is higher, the presence of more bicycle traffic acts as crowding and demotivates riders to choose that route. The study also reveals that riders prefer routes with a low volume of motorized traffic and dedicated bicycle infrastructure. The outcomes suggest that a policy that encourages infrastructural development to provide lateral separation will encourage more people, hence increasing bicycle mode share as well as the perceived safety of riders. [ABSTRACT FROM AUTHOR]

Abstract: Pedestrians on Delhi roads are often exposed to high risks. This is because the basic needs of pedestrians are not recognized as a part of the urban transport infrastructure improvement projects in Delhi. Rather, an ever increasing number of cars and motorized two-wheelers encourage the construction of large numbers of flyovers/grade separators to facilitate signal free movement for motorized vehicles, exposing pedestrians to greater risk. This paper describes the statistical analysis of pedestrian risk taking behavior while crossing the road, before and after the construction of a grade separator at an intersection of Delhi. A significant number of pedestrians are willing to take risks in both before and after situations. The results indicate that absence of signals make pedestrians behave independently, leading to increased variability in their risk taking behavior. Variability in the speeds of all categories of vehicles has increased after the construction of grade separators. After the construction of the grade separator, the waiting time of pedestrians at the starting point of crossing has increased and the correlation between waiting times and gaps accepted by pedestrians show that after certain time of waiting, pedestrians become impatient and accepts smaller gap size to cross the road. A Logistic regression model is fitted by assuming that the probability of road crossing by pedestrians depends on the gap size (in s) between pedestrian and conflicting vehicles, sex, age, type of pedestrians (single or in a group) and type of conflicting vehicles. The results of Logistic regression explained that before the construction of the grade separator the probability of road crossing by the pedestrian depends on only the gap size parameter; however after the construction of the grade separator, other parameters become significant in determining pedestrian risk taking behavior. [Copyright &y& Elsevier]

Pedestrians, cyclists, and users of motorised two-wheelers account for more than 85% of all the road fatality victims in Delhi. The three categories are often referred to as vulnerable road users (VRUs). Using Bayesian hierarchical approach with a Poisson-lognormal regression model, we present spatial analysis of road fatalities of VRUs with wards as areal units. The model accounts for spatially uncorrelated as well as correlated error. The explanatory variables include demographic factors, traffic characteristics, as well as built environment features. We found that fatality risk has a negative association with socio-economic status (literacy rate), population density, and number of roundabouts, and has a positive association with percentage of population as workers, number of bus stops, number of flyovers (grade separators), and vehicle kilometers travelled. The negative effect of roundabouts, though statistically insignificant, is in accordance with their speed calming effects for which they have been used to replace signalised junctions in various parts of the world. Fatality risk is 80% higher at the density of 50 persons per hectare (pph) than at overall city-wide density of 250 pph. The presence of a flyover increases the relative risk by 15% compared to no flyover. Future studies should investigate the causal mechanism through which denser neighborhoods become safer. Given the risk posed by flyovers, their use as congestion mitigation measure should be discontinued within urban areas. [ABSTRACT FROM AUTHOR]

• Hit-and-run accidents are a global problem to solve as an accident causing vehicle is 'unknown'. • Knowledge of unknown vehicles can be useful in better planning for ensuring road user's safety. • Experimental approach followed with six learning models - Logistic Regression, Naïve Bayes, LDA, CART, KNN and SVM to identify unknown. • Accident data from five mid-sized Indian cities- Agra, Amritsar, Bhopal, Ludhiana and Vizag is used in our experiment. • Analysis of performance of the learning models are presented with recommendations. Road accidents are globally accepted challenges. They are one of the significant causes of deaths and injuries besides other direct and indirect losses. Countries and international organizations have designed technologies, systems, and policies to prevent accidents. However, hit-and-run accidents remain one of the most dangerous types of road accidents as the information about the vehicle responsible for the accident remain unknown. Therefore, any mechanism which can provide information about the impacting vehicle in hit-and-run accidents will be useful in planning and executing preventive measures to address this road menace. Since there exist several models to predict the impacting unknown vehicle, it becomes important to find which is the most accurate amongst those available. This research applies a process-based approach that identifies the most accurate model out of six supervised learning classification models viz. Logistic Reasoning, Linear Discriminant Analysis, Naïve Bayes, Classification and Regression Trees, k-Nearest Neighbor and Support Vector Machine. These models are implemented using five-fold and ten-fold cross validation, on road accident data collected from five mid-sized Indian cities: Agra, Amritsar, Bhopal, Ludhiana, and Vizag (Vishakhapatnam).This study investigates the possible input factors that may have effect on the performance of applied models. Based on the results of the experiment conducted in this study, Support Vector Machine has been found to have the maximum potentiality to predict unknown impacting vehicle type in hit-and-run accidents for all the cities except Amritsar. The result indicates that, Classification and Regression Trees have maximum accuracy, for Amritsar. Naïve Bayes performed very poorly for the five cities. These recommendations will help in predicting unknown impacting vehicles in hit-and-run accidents. The outcome is useful for transportation authorities and policymakers to implement effective road safety measures for the safety of road users. [ABSTRACT FROM AUTHOR]