Impacts of Exit Ramp Types on Safety Performance in Florida

The study is to evaluate safety performances of different exit ramps used in Florida. Crash data were collected at 423 freeway segments throughout the State of Florida. For the freeway diverge areas, exit ramp types were defined based on the number of lanes used by vehicular traffic to exit freeways. Four exit ramp types were considered here including single-lane exit ramps (Type 1), sing-lane exit ramps without a taper (Type 2), two-lane exit ramps with an optional lane (Type 3), and two-lane exit ramps without an optional lane (Type 4). Cross-sectional comparisons were conducted to compare crash frequency and crash rate between different exit ramp groups. The result shows that Type 1 exit ramp has the best safety performance in terms of the lowest crash frequency and crash rate.