Safety performance evaluation of left-side off-ramps at freeway diverge areas

▶ The average conflict rate were about 10 per 1000 conflicting vehicles including four types, diverging, merging, weaving and crossing. ▶ The exit type of two exiting lanes without an optional lane has a higher conflict counts than the two exiting lanes without an optional lane. ▶ Left-side Off-ramps did not have significant difference in total crash counts compared to those on the right-sides. ▶ However, the percentage of severe crashes is significant higher than right-side off-ramps. ▶ Future coutermeausres should be focused on the reduction of severe crashes.