Is Slowing Down Your Speed To Save Money Worth It? We start with the premise that a driver can save $10,000 a year by slowing down his or her speed from 75 miles per hour to 65. We then set out to determine whether this would be worth it and to calculate sound, concrete numbers to back up our assumptions. Slowing down speed when rates are low and depressed is a common practice in transportation generally (e.g., ocean tankers) to pad the bottom line and effectively reduce industry capacity. The latest detailed figures we had for operating cost per mile by detailed line item were from the American Transport Research Institute (ATRI) in 2018. We used these figures to calculate how many more miles a driver would need to drive to drop the entire $10,000 in incremental profit to the bottom line. Source: American Transportation Research Institute (ATRI) Converting 2018 Operating Cost Per Mile Into Dollar-Based Expenses What we found was that to actually drop the $10,000 in savings to the bottom line, he or she would need to drive an extra approximately 27,500 miles or 90 miles per day.