With a 71:23 gear ratio, the Acela is designed with a top speed of 165 mph (266 km/h) and reaches a maximum certified speed of 150 mph (241 km/h) in regular service. The Acela Express is the only service in North America that exceeds the U.S. Department of Transportation's 125 mph (201 km/h) definition of high speed rail. The Acela achieves an average speed (including stops) of 81.7 mph (131 km/h) between Washington and New York, and an average speed of 66.9 mph (108 km/h) from Washington to Boston. The average speed from New York to Boston is a slightly faster 69.8 mph (112 km/h). The average speed for the entire length excluding stops is 84 mph (135 km/h). Its maximum speed limit is 150 mph (241 km/h) on three sections of track totaling 33.9 mi (55 km) in Rhode Island and Massachusetts.