การประเมินประสิทธิผลด้านความปลอดภัยของป้ายตำแหน่งทางข้ามบนถนนในเขตเมือง

Abstract

In Thailand, pedestrian crashes primarily result from drivers’ noncompliance with traffic rules at pedestrian crossings; for example, vehicles speeding in high-risk pedestrian crossing areas and drivers failing to yield to pedestrians. However, the underlying root cause of such problems is often a failure to notice or give priority to pedestrians. To mitigate the risks and enhance safety for pedestrians and road users, it is imperative to implement well-designed pedestrian crossings that are easily visible, promoting better visibility for drivers and leading to lowering vehicle speed and giving right-of-way to pedestrians. This research focuses on evaluating the effectiveness of High-profile pedestrian crossing signs as a measure to enhance visibility for drivers. This measure is advantageous in high visibility, low cost, and ease of implementation. However, such a measure has not been well recognized and investigated in the literature. This research aims to examine the visibility of pedestrian crossings, and evaluate the safety effectiveness of High-profile pedestrian crossing signs. First, the study examines the visibility of pedestrian crossings by assessing the Detection Distance of drivers to pedestrian crossings on urban roads. This detection distance represents the ability to warn drivers about the presence of a pedestrian crossing. In other words, it is the distance at which a pedestrian crossing can be seen. The study compares the detection distance between high-profile pedestrian crossing sign and other measures during daytime and nighttime. Furthermore, the effectiveness of high-profile pedestrian crossing sign is assessed using a Before-and-After study approach. This analysis includes an examination of the speeds and speed profiles of both motor vehicles and motorcycles across the pedestrian crossing sections before and after the installation of high-profile pedestrian crossing signs. In addition, the study analyzes the conflicts between pedestrians and vehicles, and calculates the risk reduction, which is used as a surrogate measure to evaluate the effectiveness using the Odds ratio and estimate the benefit from accident cost savings of high-profile pedestrian crossing signs. The study results reveal that the detection distance varies significantly among different pedestrian safety measures and the data collection period. On the average, detection distances are lower for nighttime conditions compared to daytime conditions. The measure with the highest average detection distance is the signalized pedestrian crossing, while the measure with the lowest average detection distance is the standard pedestrian crossing sign. Moreover, high-profile pedestrian crossing signs perform better in terms of detection distance than regular signs. The study demonstrates that these measures can reduce the mean and 85th percentile vehicle speeds by approximately 2 km/h. Drivers tend to initiate their speed reduction about 30-40 meters before reaching the pedestrian crossings. In terms of conflict analysis, the risk of conflict measured by conflict speed and post-encroachment time (PET) is reduced by 0.17, 0.01, and 0.05 for high, moderate, and low risk of conflict, respectively. The risk reduction can lead to accident cost savings and cost-effectiveness of high-profile pedestrian crossing signs.