Assessing how Drivers of through Vehicles React to Driveway Activity

As population and development levels increase in both urban and rural areas, the implementation of access management strategies is vital for creating safe, efficient, and sustainable transportation systems. To meet the changing needs of transportation systems and their users, the accuracy and the applicability of the base assumptions used to develop access management guidelines must be verified. This research effort utilized a driving simulator study to investigate several assumptions related to driver behavior and access management. The simulator study focused on driver perception–reaction time in the vicinity of driveways and driver behavior in response to differing driveway activity types. The results indicated that the average and 85th percentile perception–reaction times for all drivers were 2.8 s and 4.3 s, respectively. Surprisingly, older drivers (age 65 and older) appeared to be more alert and had an 85th percentile perception–reaction time a full second shorter than that of their younger counterparts (3.3 s versus 4.4 s). The researchers also observed that deceleration rates had a curvilinear (not constant) relationship with vehicle speed, and these values were much lower than the accepted AASHTO value of 11.2 ft/s2. Finally, the predominant response to driveway activity was a slowing maneuver, not a stop or a lane change. This finding suggests that sight distance calculations based on an urgent stop may not be the most appropriate metric for determining access spacing guidelines for commercial urban road environments.