TRB’s Transportation Research Record: Journal of the Transportation Research Board, No. 2637 consists of 12 papers that explore motorcycles, trucks, buses, and roundabouts, including: Safety Effects of Horizontal Curve Design on Motorcycle Crash Frequency on Rural, Two-Lane, Undivided Highways in Florida Investigating Total Annual Average Daily Traffic as a Surrogate for Motorcycle Volumes in Estimating Safety Performance Functions for Motorcycle Crashes Evaluation of Roundabout-Related Single-Vehicle Cr…