Speed and distance on US highways
Across the United States, vehicle speeds are measured in miles per hour (mph), and interstate distances are measured in miles and feet.
Using the formula Speed = Distance / Time, entering miles and elapsed time provides immediate calculation of average speed, pace per mile, and feet per second (ft/s).
A speed of 60 mph corresponds to exactly 1 mile per minute, or 88 feet per second.
Worked example: US Interstate travel
Driving 210 miles along Interstate 80 in 3 hours gives:
Speed = 210 miles ÷ 3.0 h = 70.0 mph (equivalent to 102.67 ft/s or 112.65 km/h).
At 70 mph, pace is 51.4 seconds per mile.
Inputs for the US speed calculator
Distance
Enter highway or route distance in miles.
Speed
Enter average vehicle velocity in miles per hour (mph).
CALCULATOR QUESTIONS
US highway speed & travel time calculator questions
How many feet per second is 60 mph?
60 mph equals exactly 88 feet per second (ft/s).
How do I calculate travel time for a road trip?
Divide trip distance in miles by expected average speed in mph. For example, 300 miles at 60 mph takes 5 hours without stops.