Effects of Bicycle Taillights and Reflective/Led Clothing on Motorists’ Overtaking/Tailgating Behaviours: an On-Field Observation Study

Background: Recent emphasis on bicycling as an alternative to automobile transportation has underscored the need for research efforts directed at bicycle safety when sharing roadways with motorised vehicles. Road segment accidents where a motorist strikes a bicycle while overtaking it, or crashes into the rear of the bicycle, have been less frequently researched. In addition, nighttime cycling has been documented in literature to be more dangerous than daytime cycling, primarily due to bicycle poor conspicuity. Past research has reported that taillights and reflective clothing are beneficial in enhancing bicycle conspicuity at nights. Objectives: The current research attempts to investigate the effects of bicycle taillights and reflective/LED clothing on motorists’ overtaking/tailgating behaviours (distances when the car overtakes and tailgates the bicycle, and the speeds of the car). Methods: Four types of taillights will be investigated: (a) no light, (b) flashing light, (c) static light, and (d) laser-icon light that illuminates a bike icon on the ground. Four types of reflective clothing will be examined: (a) black condition: no reflective clothing, (b) vest condition: the cyclist wears a reflective vest; (c) ankle and knee condition: the cyclist wears black shirt, together with reflective strips around the ankles and knees; and (d) combined condition: the cyclist wears black clothing, together with a vest and reflectors around the ankles and knees. As for LED clothing, the same procedure will be applied for evaluating the effects of 7 different colours and different LED modes (flashing VS static). An on-field observational study will be conducted for collecting data on urban and rural road segments in Taipei City and New Taipei City, respectively. Considering other variables (e.g., cyclist attributes, vehicle characteristics, temporal factors, environmental/roadway characteristics), the on-field study will endure three years: study 1 (year 1) will evaluate the effects of four types of taillights; study 2 (year 2) will investigate the effects of four types of reflective clothing; and study 3 (year 3) will examine the effects of LED clothing, and which colour of LED clothing is the most beneficial. Equipments such as laser distance measurer, speed camera, video camera, will be used by the trained research assistants for collecting data. Statistical analyses will be conducted for identifying which conspicuity treatment(s) is more beneficial to bicycle safety. Linear regression models, binary logit models, and mixed logit models will be estimated for investigating the determinants of car drivers’ crowding behaviour. Expected results: Expected research outcomes include that several types of conspicuity treatments can be the most beneficial to bicyclists (a) laser-icon taillight, (b) biomotion reflective/LED clothing, (c) flashing and yellow LED. Contributory factors to drivers’ crowding behaviour include (a) taxi, (b) larger vehicles such as buses/coaches or HGVs, (c) absence of conspicuity treatment, (d) urban streets, (e) presence of an oncoming vehicle, (f) male cyclist, and (g) young cyclist. The results of the research will help provide the policy-makers with suitable policies/strategies that could further reduce bicycle crashes relating to drivers’ tailgating and overtaking manoeuvres, and curb their crowding behaviours when sharing roadways with cyclists.