Effect of Intersection Channelization and Skew on Driver Performance

Abstract

This field investigation studied the effects of the geometries of right-turn lanes on the turning performance of drivers with respect to driver age and gender. Right-turn performance of 100 subjects within three age groups (25–45, 65–74, and 75+ years old) was evaluated under normal driving conditions at four intersections of different right-turn lane channelization and skew. The results indicated that right-turn channelization affects the speed at which drivers make right turns and the likelihood that they will stop before making a right turn on red (RTOR). Drivers, especially middle-aged (25–45 years old) drivers, turn right at speeds 5 to 8 km/h higher on intersection approaches with channelized right-turn lanes than they do on approaches with unchannelized right-turn lanes. Also, drivers are much less likely to stop before making an RTOR on approaches with channelized right-turn lanes. Drivers are less likely to attempt to make an RTOR at a skewed intersection where the viewing angle to traffic from the left on the cross street is greater than 90 degrees. Also, drivers turning right at these locations are more likely to use their side mirrors than they are when making an RTOR at nonskewed intersections.