Abdulla Alghafli

Abu Dhabi’s government has taken several initiatives to improve the safety of the city’s highways, such as reducing traffic accident occurrence, red light violations, and property damage associated with traffic accidents. However, the intersections are still associated with many severe accidents, property damage associated with accidents, and red light violations. To help authorities pinpoint the major contributors to the deterioration of the safety performance of the signalized junctions, this study employed a negative binomial regression model to investigate the effect of geometric road conditions (in terms of the number of lanes of streets found in four-leg, three-leg, and different types of intersection) on property damage, red light violations, and severe accidents as safety performance indicators. The research found that, in both three-leg and four-leg intersections, most accidents and traffic light violations occur when minor streets pass through the intersection. This can be solved by converting these minor streets into major streets by increasing the number of lanes. This way, the capability of the minor street’s handling of increased traffic from the major streets significantly increases. The results also show that traffic speed is a major contributor to safety performance deterioration in these intersections. This can be solved by posting speed limits at these intersections. Results have also shown that, in Direction 1, when the main street passes through the intersection, the property damage type of accident is significantly high. This may be due to the presence of a potentially hazardous property or road design flaws on that side of the road. This effect needs further investigation to determine the hazardous property or the road design flaws causing these accidents.

Few studies have been carried out in UAE relating red light violations to a number of factors, such as speed limit violations, geometric design of the intersection, and the elapsed time from the onset of red signal until the time of the violation to the occurrence of the accident. This study bridges this gap by attempting to investigate the relationship between the elapsed time from the onset of red signal and the occurrence of the accident. To achieve this objective, Poisson’s regression, between occurrence of accident and elapsed time from the onset of red signal and the occurrence of the accident at various geometric designs of intersections (3-leg and 4-leg), was carried out. The research found that at 4-leg intersections, almost all red light violation related accidents occur between 1 to 2 s from onset of red light until its violation time. The research also showed that at 3-leg intersections, most of red light violation related accidents occur in less than 1 s from the onset of red light until violation time. It was also found that at lead lag signalized intersections, regardless of the type of the intersection, most accidents tend to occur between 2 to 3 s from the onset of red light.