The Relationship between Free-Flow Travel Speeds, Infrastructure Characteristics and Accidents, on Single-Carriageway Roads

This study explored the relationship between travel speeds and accidents on single-carriageway roads, accounting for traffic exposure and road infrastructure characteristics. The speed data are free-flow travel speeds collected by GPS devices inside the vehicles. The study's database included 179 sections, in Israel. Negative binomial statistical models were fitted to injury accident counts, in day- and night-hours, using speed indicators, section length, traffic volume and homogeneous road groups, where road groups reflect various road design conditions. The models demonstrated a positive relation between mean speeds and accidents, while controlling for traffic exposure and road infrastructure characteristics.