Add the distances traveled from each segment of your trip. For example, if you had a three day road trip and you traveled 400 miles on the first day, 350 on the second and 380 on the third, you would add 400 plus 350 plus 380 to find the total distance to be 1,130 miles.
Add the time spent on each segment of the trip. In this example, if you traveled 9 hours on the first day, 7.5 on the second day and 8 on the third, you would add 9 plus 7.5 plus 8 to get a total of 24.5 hours.
Divide the total distance traveled by the total time elapsed to find the net speed. Completing the example, you would divide 1,130 miles by 24.5 hours to find your average speed equals about 46.12 miles per hour.