Freeway deceleration lane lengths effects on traffic safety and operation

The safety and operational analysis results suggest that (1) for one-lane exits, a minimum deceleration length of 500 ft is essential for the design speed of 55 mph, 600 ft for the design speeds of 60 and 65 mph, and 700 ft for the design speed of 70 mph; (2) for two-lane exits, the minimum deceleration length of 500 ft is suggested for the design speeds of 55 mph and 60 mph, 600 ft for the design speeds of 65 and 70 mph; and (3) for both one-lane and two-lane exits, deceleration lane lengths longer than 700 ft are not recommended from a safety perspective. The results of this study could be used as a supplementary to the current design guideline.