Effect of Centerlines and Edgelines on Driver Speed Selection and Lane Positioning on a Low-Speed Urban Collector Street

This study investigated the effects of centerline and edgeline presence on driver speed selection and lateral positioning behavior on a low-speed urban collector street. The study was conducted along a two-lane two-way street segment that had been recently reconstructed, which allowed for the centerline and edgeline markings to be installed in separate phases. Cameras were used to record vehicle speed and lateral position data at five locations along the corridor during each striping phase, which included: (1) no striping, (2) centerline only striping, and (3) centerline plus edgeline striping. Linear regression models were developed to assess the impacts of striping configuration and roadway cross-sectional characteristics on speed and lateral position. The absence of any longitudinal striping resulted in speeds that were 0.8 mph lower than when a centerline was present and 2.3 mph lower than when both a centerline and edgeline were present. In terms of lateral position, drivers were positioned closest to the center of the roadway when both the centerline and edgeline were present and shifted approximately 1-ft further to the right when no edgeline was present (with or without a centerline). Furthermore, the combined use of centerlines and edgelines resulted in a more uniform vehicle lane position along the corridor, with reduced lateral variability during roadway width transitions or when vehicles were parked along the curb. Collectively, the findings provide preliminary evidence that the exclusion of longitudinal pavement markings contributes to lower speeds and generally more cautious travel along two-lane, two-way urban collector streets.