Pedestrian Safety Evaluation at Signalized Intersections Using (SSM)

Abstract

Urban traffic management and transportation engineering best identify areas related to pedestrian safety at signalised intersections. Despite the increase in infrastructure and signal control systems, pedestrians continue to be vulnerable road users, who are at risk at disproportionate rates compared to motorists. However, current traditional crash-based safety evaluation techniques are poor in predicting risk because of the relatively low frequency of collisions that occur between pedestrians and vehicles, thus creating unreliable estimates of the risk and delaying the implementation of preventive strategies. Therefore, in this study, the evaluation of pedestrian safety is achieved using Surrogate Safety Measures (SSM), namely, Time to collision (TTC), Post encroachment time (PET) and vehicle pedestrian conflict rates. The SSMS contribute proactively in identifying near misses and high-risk situations before accidents happen. A high volume network of signalised intersections was studied in the mid-sized urban environment, and data were collected. Detailed movement paths of both vehicles and pedestrians were extracted using advanced video-based trajectory analysis tools. Trajectories from these methods were calculated, and SSMs were calculated and analysed for different intersection designs and operational conditions. The results showed a strong positive correlation between the conflict rates that are elevated, lower TTC and PET values and historical crash records, indicating the effectiveness of SSMs as useful measures of pedestrian risk. In addition, certain geometric configurations were shown to be important factors in terms of increased conflict rates, including broader crossings as well as insufficient pedestrian clearance intervals. The study proposes targeted engineering treatments and signal timing modifications based on these findings. The research shows the need to incorporate SSMs in the current practices of traffic safety management and lead it in a proactive approach toward mitigation of risk.