With fuel prices creeping up again I thought it appropriate to share some of my experiences with hypermiling. “Hypermiling” is a method of increasing your car’s gas mileage by making changes in the way you drive. It can also include changes in the way you maintain your car, including tire pressures, fuel grade, and oil viscosity.
I recall my father telling me about over-inflating his tires during WWII rationing. This is sensible if the value of conserving your fuel ration to get around is more important than optimal traction or wearing the tires bald. Years ago I was also intrigued by a Shell experimental car that got 149 MPG. This was fantastic at a time when the typical American land yacht was getting maybe 12 MPG and it seemed the only thing people really cared about was the brand of car they drove, its stylish looks and, of course, its power.
I think I’ve been practicing hypermiling to some degree for years, but mainly to reduce the wear and tear on the vehicle. For example, I go over 100,000 miles between brake jobs.
I drive a well-maintained 1998 Toyota Avalon, a medium size vehicle by today’s standards. Incidentally it is also an extraordinarily reliable car. It has a 6-cylinder, 3.0 L, 200 HP engine – an abundance of power to negotiate all road and highway situations. The sticker EPA mileage is 19 MPG city and 27 MPG highway. I don’t think my wife or I have ever gotten less than 23 MPG even with aggressive driving. Getting around LA, where we live, means driving freeways, so “city” mileage only loosely applies. Often we’ll average around 27 MPG.
In the summer of 2008 when the price of a gallon in LA shot up to about $4.50 plus or minus, I really started getting into driving techniques to push up the car’s mileage. This is when, by the way, I first heard about “hypermiling”. Modest accelerations, anticipating the signals, coasting where possible (legally in Drive, of course), limiting the freeway speed, and inflating tires to their upper limit were the principle techniques. There are other techniques I’ve read about of questionable safety – drafting, for instance – or that are just plain illegal – like rolling through stops. You don’t need to do these to achieve a substantial increase in mileage.
Initially I achieved over 29 MPG without a great deal of effort. With practice and adding in refinements like turning off the engine at long stops, I achieved the benchmark level of 30 MPG. By dropping down my top freeway speed to 60 MPH and practicing really careful acceleration/deceleration technique, I topped out at over 31 MPG with a car rated by the EPA at 21 MPG overall.
That works out to 13% less fuel usage compared to normal “conservative” driving, a 26% reduction compared to “aggressive” driving, and a 32% reduction compared to the EPA overall rating. This represents real energy and cost savings.
In LA, and probably any major city, hypermiling requires patience and a certain “thickness of skin”. There’s a world of impatient drivers out there and the practice of hypermiling will automatically increase the number of these drivers apparent to you. It also requires continuous attention to your driving technique to make it work. I have to admit that once the fuel prices came tumbling down, I reverted back to normal driving technique. If gas prices shoot back up, I’ll probably re-join the hypermiling club.
Randal Ferman, PE