maybe most people dont have a long don't commute 40 miles each way to work and back.

but i do. also my  avg mile per gallon goes up at one constant speed 65-70mph. but i do have to leave 10-15 min early to get to work on time. going home i drive 65 and get home 15 mins later than driving 75 to 80.

also drive in the second lane so you dont have to slow down while cars are merging on to the freeway.