Based on measuring 46 car trips in my 1993 Dodge Van, with many trips starting from my El Granada neighborhood, here is a formula for the time required to drive places in a car:
- Given the distance in miles measured as a bird would fly (great circle miles)
- Time = 1.41 minutes per mile + 12.09 minutes
- The measurement covered 46 vehicle trips.
- Average distance was 7.90 miles.
- Average trip time was 23.2 minutes.
- Average speed for all trips was 17.72 miles per hour.
1.41 minutes per mile implies 42.55 miles per hour... (take the reciprocal and multiply by 60 to convert miles per minute to miles per hour).
That is pretty reasonable as my neighborhood has mostly 45 and 50 mile per hour speed limits on Highway 1.
The travel time formula is an approximate empirical constant that reflects the performance of a car as a transportation device.
So a car trip consists of "About 12 minutes plus you move toward the destination at 42.55 miles per hour."