3 Speed Management
3.3.3 Target Crash Population
The dynamic curve speed warning systems highlighted above target the population of crashes on horizontal curves. Both systems are aimed at reducing truck crashes, and in at least one case have been highly effective.
According to a FARS query(2) in 1998, there were 615 fatal rural crashes (with known road class, vehicle configuration, and roadway alignment) involving trucks (single unit trucks, truck/trailers, truck tractors, bobtails), tractor semitrailers, and other medium/heavy trucks) on curves.
Bad curves are a localized problem, and these systems should provide their maximum potential payoff for curves or a series of curves with frequent truck crashes due to excessive speed. Widespread applications of such systems on curves without frequent crashes may lessen their effectiveness.