Steve Shekari Presents at TRB Annual Meeting 2021

On January 28, 2021, Steve Shekari co-presented a virtual poster presentation at Transportation Research Board’s 2021 Annual meeting. Steve and group of scholars wrote a paper titled, “Designing Crossing Islands for Speed Control and Intersection Safety on Two Lane Collectors and Arterials.”

Steve shares his abstract:

“Crossing islands at unsignalized intersections, in addition to their pedestrian crossing safety benefits, can also serve as speed control chicanes by forcing vehicles away from their straight path and making a reverse curve. In this study, a method is developed for determining the chicane length needed for a given lane width, island width, and target speed, based on models of the relationship between road geometry, vehicle path radius, and speed. New data on the speed-radius relationship is presented. The concept of  “informal flare” is also introduced, which is a common approach geometry being referred to flaring a lane just wide enough to allow a left-turning vehicle to wait for a gap in opposing traffic without blocking through traffic behind it within the same lane. Using informal flares can make it possible to prevent left-turn blockage without adding an exclusive left turn lane, which may result in sacrificing a crossing island. Curb continuation pavement markings at median openings are presented as a means to enhance informal flare function. The study also presents original data which relates informal flare function (the tendency of through vehicles to bypass a waiting left turner) to a road’s half-width. Geometric analysis shows that intersections with crossing islands can fit on roads with right of way as narrow as 60 feet while still accommodating turning school buses and preventing left turn blockage. Performance measures used to evaluate intersection geometry include speed of through vehicles, speed of left-turning vehicles, pedestrian exposure distance, pedestrian path length, pedestrian path heading deviation, parking loss, ability to accommodate large turning vehicles, and ability to avoid blockage by left-turning vehicles.”

Congrats Steve!