Road safety implications of bus only lanes and bus drivers junction approaching behaviour

Abstract

In Hong Kong, franchised buses, which share over one-third of daily journeys, play an important role in the public transport system. Whether they are being safely operated on roads is crucial to the government and public, but little attention has been paid by local researchers. This study therefore aims to look into two specific issues, which are expected to be crucial to the operation safety of buses. First, safety impact of the bus-only lane (BOL) system was studied. The BOLs in Hong Kong are mostly adopted in heavily trafficked corridors, similar to other major cities such as London and Seoul. This measure is aimed to improve bus service reliability by rationalizing road space usage, and hence to further increase bus modal share. Its safety issue has however generally been neglected. The conventional Before-After observational study technique and an alternative method were adopted to conduct an evaluation on this issue. Of the seven studied roads with BOLs, decreases of public bus accidents, both the fatal and serious (FS) and fatal, serious and slight (FSS) were reported; while increases of other vehicle FS accident were found. The results appear to suggest that public buses have been benefited from the BOL operation, but non-bus traffic had not or even had been harmed by that. Second, the driving behavior of bus drivers at signalized junction where most accidents occurred was studied. Through the experiences on red-light violation and Dilemma Zone (DZ) problems, the investigation of this study looked into driver approaching maneuver and decision-making behavior. Hypothesis tests and binary choice models were adopted to assess the performances of bus drivers at the studied junction. As was commonly expected, bus drivers reported to have better performances in response to facing decision dilemma at the start of amber. The dilemma area where the drivers confront Stop/Go decision was relatively small. Apart from the simulation model, the hypothesis test results reveal that bus drivers did adjust their approaching speeds at the times near the end of green signal. Such an action helped their responses to dilemma situation and attributed to their better performances. The results infer that the drivers could have higher consistencies in making Stop/Go decision at amber with the provision of signal information. Junction safety could thus be enhanced. The significances of this research study are: a) it is the first time that the impacts of BOL system on road safety were identified; b) it is the first time that the driving behavior of bus drivers at signalized junction was identified, both in the periods of amber and prior to the start of amber. These findings will contribute tothe safety design of BOLs and the effective trainings of bus drivers.