Driving Speed	Driving Time for  4 miles	Time lost by slowing below  60 MPH	Stopping Distance	Braking Improvement below 60 mph
60 mph	4 minutes	-----	240 ft.	-----
50 mph	4.8 minutes	48 seconds slower	175 ft	65 feet faster stop
40 mph	6 minutes	2 minutes slower	120 ft.	120 feet faster stop
30 mph	8 minutes	4 minutes slower	75 ft.	165 feet faster stop