Hypermiling

Posted on June 9, 2008

With gas at four bucks a gallon, some folks still enjoy filling up. It’s a contest, a chance to see how many miles one can squeeze from every tank.

It’s called hypermiling. It’s a growing number of people going to all kinds of extremes to see how far they can go on a tank of gas. Like a videogame, the hypermiler is always working to post a new high score.

It’s a game that some say started during the gas-rationing days of World War II and came back during the oil embargo of the 1970s. It’s catching on again as fuel prices spiral out of sight, and skilled players say small changes in driving style — eliminating hard acceleration, turning off the engine at stop lights, coasting to a stop — can bring big improvements in fuel economy no matter what you drive.

One of the techniques being used is called ‘pulse and glide.’ Its name comes from the process of turning off the engine and coasting. Pulse and glide is controversial — and in some states, illegal — because the engine drives the power steering and brakes. Shut it off and you are unable to steer or stop effectively. Hypermilers say the risks are overstated. Still, there are easier — and, arguably, safer — things you can do to boost fuel economy. The single most effective thing you can do to improve mileage is drive the speed limit. The U.S. Department of Energy says gas mileage plummets above 60 mph. Every 5 mph above that speed is like paying another 20 cents a gallon for gas. For that reason, hypermilers scrupulously obey the speed limit. They also use the accelerator and brake as little as possible, preferring instead to coast. The truly hardcore coast to a stop, avoid using brakes around corners and draft behind trucks or other large vehicles.

In addition to those things, the really serious ones install gas consumption gauges to monitor real-time usage. They also do things like modify the aerodynamics of the underside of the car to improve airflow and mileage.