Updated: Nov 2, 2021
Being on time is an important part of being an Owner-Operator. After all, you are building a reputation and creating trust that you are a reliable business person. It is tempting to drive faster to get to your destination, but as a business owner and an Owner-Operator, fuel is your highest cost and something you should be watching daily. Speed is still the number one driver of high fuel consumption. You want to be on time, but you also need to know the true cost of driving faster.
Example A: Here is the cost for driving 120,000 miles and sacrificing one mile per gallon by driving fast. If you get 6.0 miles per gallon = 20,000 gallons of fuel to purchase and pump into the tanks. If you get 7.0 miles per gallon = 17,143 gallons of fuel to purchase and pump into the tanks. This is based on the average of $4.15 per gallon x 2,857 extra gallons of fuel= $11,856 extra costs for getting 6 mpg instead of 7 mpg.
Driving fast does not just burn more money in fuel. Below are the additional costs for driving fast.
Maintenance. Increasing your speed means increasing your cost for maintenance. As speed increases, you automatically increase wear on the brakes, tires, engine and suspension, plus the cost of downtime for repairs and maintenance. The cost of this extra maintenance could easily be one cent per mile for a total of $1,200. Given the increased fuel cost, plus increased maintenance costs, the total additional cost is $13,056.
Engine. You can only run so much fuel through an engine before it wears out. The life of an engine is limited by the amount of fuel it will burn. And it’s proven that the faster you drive the more fuel the engine will consume on a per-mile basis. So the faster you drive, the faster you wear-out your engine and this one thing alone could exceed one cent per mile in costs.
Tires and Suspension. Sometimes you can find a smooth road, but very few of our roads and highways are without bumps, potholes, cracks, and seams in the surface. Higher speed means a greater impact on tires and suspension when rolling over bumps, cracks, and seams in the pavement. More impact = more or faster wear on a per-mile basis. More impact = shorter life for tires and suspension. The main enemies of a tire are heat and impact damage, and you will have more of this damage with higher speed. Heat from under-inflation is probably the single biggest hazard to a tire.
Brakes. The higher the speed, the more brakes have to be used. The more often brakes are applied and for a longer duration will mean the brake pads need to be replaced more often. Lower speed = lower brake usage. Also, it’s more likely that a “hard stop” or “panic stop” will occur at higher speeds. Only one or two hard stops are going to cost money in tires and brakes and it’s not uncommon for aggressive drivers to have one or two hard stops per day.
There might be a time when you must drive fast to be on time, but what is the true impact?
Fill-ups. The average fill-up is 101 gallons, according to a study conducted of ATBS’ Owner-Operators. The average time needed to fill-up is 1 hour. Twenty-eight extra fuel stops are required x 1 hour each = 28 extra hours to replace the extra fuel burned. So the faster you burn fuel, the faster you have to replace it. Talk about diminishing returns! How much speed does it take to replace $13,056 and 28 hours? The faster you drive, the faster you have to replace the fuel and the faster the wear on your tractor and tires.
There’s no argument that driving faster can save time, but what’s the trade-off?
Example B: If you drive 450 miles at 75 mph, you will save about 1.5 hours of time versus driving at 60 mph. However, fuel economy will suffer at the higher speed and the difference is usually about 1.5 MPG when comparing 75 mph and 60 mph. The engine burns an extra 1/10 of a gallon of fuel for every mile driven over 55 mph. The difference between 60 and 75 mph would then equal 1.5 mpg. This would cost you 20 gallons of extra fuel or $83 of extra cost when fuel is at $4.15 per gallon. This calculation is an industry standard and is set by engine manufacturers. This formula is also found in the “Cummins MPG Guide.”
Add the extra maintenance cost of a penny per mile and the total cost is now $87.50. Is the 1.5 hours worth $87.50 to you? You’re the best person to decide, of course, but don’t think speed is free. The extra time saved will cost you something for driving faster. How do you spend the extra time gained by driving fast? Did you get repaid for the extra $87.50 you spent?
Is it ever more cost effective to drive faster?
If you are on a “loose” schedule by all means slow down to the optimum road speed to conserve fuel. There is a balance between speed and the cost but speed isn’t cheap and it’s not free!
Example C: Suppose you have a pick up in Chicago on Thursday afternoon to be in Omaha Friday morning. That’s 500 miles basically overnight. Very doable but the driver cannot be late because the consequences of a late delivery (or being at the back of the line for trucks delivering) are too great.
Consequences like laying over from Friday to Monday will cost you about $300 in just fixed expense alone. The layover cost in this case is more than ALL of the fuel cost for the entire trip. There are other financial penalties beyond layover cost so the driver would be wise to operate at the higher but less fuel efficient speed to safely insure delivery with no chance of layover in Omaha. The speed limit across Iowa on I-80 is 70 mph while the most fuel efficient speed might be around 62 mph. Driving at 70 mph would cost the driver about 8/10 of a gallon of MPG for the trip or about 10 gallons of extra fuel consumed between Chicago and Omaha. Ten gallons of fuel is probably a good trade-off to make in some circumstances.
You control your truck’s consumption of fuel. There may be special circumstances that will be more cost effective for you to drive faster, but this is not common. Carefully manage the balance between your speed and the many costs of increasing your speed so you save the most money possible.