BOSTON — Rep. Dan Winslow wants to raise the speed limit on certain stretches of interstate highways in Massachusetts from 65 miles per hour to 70 miles per hour. “Our roads are designed for 70. Our cars are designed for faster than 65,” Winslow told the Committee on Transportation Tuesday. If approved, the bill (H 3175) would increase the speed limit on parts of the Massachusetts Turnpike, Interstate 91, and Interstate 95. Newton resident John Carr, who told the News Service highway speeds have been “an interest of mine for about 15 years,” favors an increase in the speed limit,...