Safety Evaluations of Innovative Intersection Designs for Pedestrians and Bicyclists

DTFH6116D00039L/693JJ319F000377/P00002The protected intersection is a type of innovative intersection design. Traffic professionals are exploring protected intersections to determine if they can successfully accommodate multimodal transportation by reducing conflicts between moving vehicles and vulnerable users (VU) or by lowering the impact force (reducing the vehicle speed and changing the collision angle in the event of a collision). For this Federal Highway Administration project, data were collected at 6 intersections both before and after the treatment was installed (for 12 site periods), at 14 intersections where the treatment was present (representing 14 site periods), and at 4 intersections where the treatment was not present (termed comparison sites and representing 4 site periods). Technicians recorded behaviors for 23,505 VU at these 30 site periods. Drivers yielded to bicyclists and pedestrians more at the treated sites compared to the untreated sites. For bicyclist crossings, 38 percent of the crossings for treated sites compared to 34 percent for untreated sites involved a vehicle yielding to the bicyclist. For pedestrian crossings, the comparison is 23 percent for treated sites compared to 16 percent for untreated sites. The protected intersection treatment is designed to slow turning vehicles and provide drivers additional opportunity to see the crossing VU. The addition of the treatment at three of the before-after sites with traffic control signals resulted in more frequent yielding by drivers to pedestrians (41 percent in the before period to 47 percent in the after period). Right-turn speeds are higher at a larger corner radius. Reducing the corner radius with the installation of the treatment resulted in a decrease in the speed of right-turning vehicles. Prediction equations were generated, and for a corner changed from a 60-ft radius to a 25-ft radius, a decrease in speed of about 2.6 mph is predicted. Including truck aprons can facilitate the turning of large vehicles while also encouraging smaller radius turns for right-turning vehicles