D. Relph, A. Al-Kaisy, R. Gleason

Pages: 117-130

Abstract
This study aims at examining drivers’ behavior in the presence of bicyclists utilizing the side of rural highways. Specifically, the study focuses on how drivers react to the presence of bicyclists while passing them along a recreational route consisting of a two-lane rural road. This study may be useful for touristic areas such as state and national parks and forests which have seen increasing use by bicyclists in recent years. Using field data collected via radar traffic recorders and video cameras at two study sites, several variables were tested for the influence bicyclists have on driver behavior. Two indicators of drivers’ reaction were used: vehicle speed and the lateral position in the travel lane. Three other variables were tested for their effect on the two aforementioned variables: time to vehicle arrival in opposing lane, time between a bicycle and a vehicle arriving at the site, and vehicle class. There were 189 bicycles observed at site 1 and 182 at site 2 resulting in 530 motor vehicle data points for site 1 and 437 for site 2. Study results suggest vehicle speed and lateral position are both affected by the presence of bicyclists. Further, the affects were primarily seen when the vehicle was observed within 10 seconds or less of a bicycle passing the site, or within approximately 400 feet of distance. There was still some affect up to 20 seconds. Study findings also showed a correlation between vehicle lateral position and selected travel speeds during bicycle passing events.
Keywords: rural two-lane highways; bicyclists; driver behavior