Thank you for this question. It concerns such a recent phenomenon that it indicates our readers are up to the minute on important issues. It's also totally LVA-like, a frugal way to save money on gasoline, as well as a nearly effortless way to reduce -- individually, gallon by gallon -- the world's dependence on oil.
Hypermiling came about as a result of the throwaway phrase, "Actual mileage may vary." The "movement" originated with the owner of a gas-electric manual-transmission Honda Insight hybrid, who, using his car's gas-saving technology, averaged more than 90 miles per gallon for more than a year (Honda’s mileage estimate for the Insight is around 57). Later, he was part of a team that drove another hybrid, a Toyota Prius, for more than 1,200 miles on a single tank of gas (featured on an HBO Earth Day Special "Too Hot Not to Handle").
Basically, hypermiling means modifying your driving habits to greatly improve your gas mileage (and reduce emissions).
How?
Some techniques require nothing more than common sense. For example, driving the speed limit. In most cars, 38 miles an hour is the optimum speed for miles per gallon; anything higher costs you in fuel economy. (For every five mph above 55, you can lose as much as 10% of your fuel efficiency. Those of us who remember the "gas shortages" of the early 1970s also recall that the national speed limit was reduced to 55 mph.) Simply put, slowing down gives you better mileage. Just make sure you’re in the right-hand lane and not blocking the smooth flow of traffic.
Another common-sense driving technique: Optimize your route. Look to reduce time spent at red lights. (Idling at lights gets zero miles to the gallon.) Try to drive when traffic is smooth and not stop-and-go. Sometimes a longer route with better driving conditions uses less gas.
Keeping your tires properly inflated saves on gas mileage: A lot of extra gasoline is required to roll even slightly flat tires. Also, changing the oil regularly can have a significant effect on mileage: The thicker the oil, the more energy it takes to push it through the engine.
Some techniques require slight changes in driving habits. A good hypermiling method is known as DWB, or driving without brakes. Continuously accelerating and braking is highly inefficient. Instead, maintain a steady speed. For example, if the car in front of you is speeding up, let it. It'll get ahead of you, but when traffic starts to slow down, you'll catch up. And the other car will have used more gas than you.
Coasting in neutral is perhaps the best technique. This works best driving down hills where you can maintain a steady speed -- slowing down, even gradually, tends to anger drivers behind you. Some hypermilers spend more time in neutral than they do in drive, especially in hilly country. Hypermiling heaven is maintaining the speed limit in neutral, with no one in front of you to slow down your momentum and no one behind you to get irate as you lose momentum. Meanwhile, the tachometer is hovering around zero rpms while the odometer is clicking off the miles, using the least gas possible.
Some hypermiling techniques are a bit controversial. On the hypermiling forums, arguments rage about over-inflating tires. Added air pressure reduces friction (saves gas), but it also compromises traction (sacrifices control). And the most radical hypermilers actually turn off their engines while they’re driving to use no gas whatsoever. This reduces the efficiency of the hydraulics (power steering and power brakes), among other things. Also, you need a manual transmission to do this; most cars with automatic transmissions have to be in park for the electric ignition to work, which can be inconvenient, for example, on the freeway.
Specific to Las Vegas, especially in a rental car, hypermiling can be of some value. You can make sure the car’s tires are properly inflated. You can stay off the Strip at all costs to avoid stop-and-go traffic and idling at red lights. You can drive the speed limit and try to maintain your momentum with DWB.
And you can coast in neutral on those rare occasions when you’re traveling downhill. Las Vegas Valley is pretty much as flat as a mackerel, but in general, it’s tilted from west (higher) to east (lower). As you’re driving east, especially on the west side between Jones and Decatur, you can ride a bit of gravity and save a little gasoline.
No matter where you are, though, anyone can be a hypermiler. It doesn't matter if you're in a Honda Insight hybrid or a Hummer H2 -- You can employ some of these techniques and get better gas mileage.
