In the movie JD has 10 1/2 hours of driving. This is correct if you are going an average of 65mph you will make it in 10 3/4 hours if he drove an average of 75mph he would make it in 9 1/3 hours. Lets say he drove 100mph he would have made it in 7 hours. Most people drive about 9mph over the posted limit. Most highways outside of the city are 65-75mph. So to not get pulled over he would have made it in 8 1/3 to 9 1/2 hours