Gap acceptance for left turns from the major road at unsignalized intersections

This paper attempts to identify factors that may influence the gap acceptance behavior of drivers who turn left from the major road at unsignalized intersections. Drivers’ accepted and rejected gaps as well as their age and gender were collected at six unsignalized intersections with both two and four lanes on the major road, with and without the presence of a Left-Turn Lane (LTL), and with both high and low Speed Limits (SLs). Whether or not a driver accepts a given gap was considered as a binary decision and correlated logit models were used to estimate the probability of accepting a gap. Models with different factors were tested and the best model was selected by the quasi-likelihood information criterion. The gap duration, the number of rejected gaps, the mean and total time interval of the rejected gaps and the gender of the driver were all significant in explaining the variation of the gap acceptance probability, whereas the number of lanes of the major road, the presence of LTL, the SL and the driver’s age category were not. Gap acceptance probability functions were determined based on the best model, including both the factors of the number of rejected gaps and the mean time interval of the rejected gaps. As the values of these two factors increase, the probability of accepting a given gap rises up. The developed model can be further applied in practice to improve the analysis of traffic operations and capacity at unsignalized intersections. First published online: 10 Jul 201

Key areas of traffic safety work according to European experts

Upprättat; 1998; 20080818 (andbra

Promoting safe walking and cycling

Upprättat; 2000; 20080818 (andbra

A safe environment for children and elderly as pedestrians and bicyclists : A synthesis based on an analysis of in-depth studies of fatalities, police-reported crashes and behaviour studies

Children frequently lack the ability to correctly direct and maintain their attention on traffic, to judge speeds, and localize sounds. Compared to adults, they also have more limited cones of visions, less capacity to perform multiple tasks simultaneously, and less ability to control their impulses. Elderly people because of the ageing process sometimes lack the ability to correctly comprehend the traffic situation. Therefore special attention has to be given to the design of the traffic environment for children and elderly. Based on a literature review, a number of hypotheses are formulated to describe factors that are decisive for determining whether crashes involving children and elderly will occur or not and the severity of those crashes. Swedish and Finnish indepth studies of crashes, police reported crashes, conflict studies and data describing 11 738 video filmed pedestrian and bicyclist passages have been analyzed to test these hypotheses. The factors that contribute to crashes are identified and a set of principles are proposed when designing urban traffic environments for children and elderly to eliminate these causes. The main principle proposed is that actual vehicle speeds should be no more than 30 km/h wherever children or elderly cross streets. Complementary countermeasures are proposed for children and elderly to see and bee seen and to improve orientation.Godkänd; 2004; 20080919 (andbra