With petrol breaking the R10 barrier today, I’m sure the newspapers will be hauling out the AA’s list of fuel-saving tips yet again. We’ve all read them least a dozen times. The list is generally sound: use the correct tyre pressure, don’t accelerate too quickly, etc., etc., etc. Our eyes are glazing over, however. It’s time for a new list. It’s time to push the envelope.

The fuel consumption numbers in the literature for new cars (and now on windshield stickers in South Africa) are useful for comparing between cars. But few people can keep their fuel consumption that low on the streets. The official stats are derived under very controlled conditions that don’t really reflect the habits of typical drivers.

I hate to brag, but I do consistently match or beat the official fuel consumption figures for the cars I drive. You can, too. Follow me.

[Lawyer's note: Use these tips at your own risk. GreenerHouse is not responsible for your prang. Safety first.]

1. Don’t brake.
2. Hold your right foot in the air
3. Watch your rev counter
4. In town, windows down
5. Ride the roller coaster
6. Drive your spouse’s car
7. Change your clocks
8. Know your numbers
9. Rearrange your “To Do” list
10. Drive farther . . .

1. Don’t brake

Ok, if a ball rolls out into the street with a child running behind it, slam on the brakes, but most braking is an unnecessary waste of energy. You must learn to feel guilty every time you brake, converting all of that good momentum your engine has given you into wasted friction and heat, requiring you to accelerate all over again.

Not braking requires planning ahead, allowing space in front of your vehicle and exercising patience. A typical example is a street with speed bumps. Most drivers accelerate after each bump and brake before each bump. It makes no sense. The bumps are there because the people who live on that street convinced the government that cars should drive slowly for the safety of the neighbourhood’s children and pedestrians. Settle into the speed at which your car can handle the bumps and stay there. Unless you’re heading downhill, you shouldn’t have to brake.

Look way ahead to the traffic lights and let your car slow naturally well in advance of a red light. People are always in a hurry to sit at a red robot, wanting to give the poor smash-and-grabbers a sporting chance. Don’t worry about the guy behind you flashing his headlights. You’re saving him petrol and a smashed window, too. Smile and wave.

If you have to brake at the bottom of a hill or before a curve, it probably means that you were accelerating unnecessarily a few moments before. Slow down in advance—it’s not safe to brake on a curve, anyway—and keep your foot off that darned brake.

2. Hold your right foot in the air

Many drivers apparently have weak quadriceps in their right leg. The foot at the end of it can always be found resting on either the accelerator or on the brake. I spend a tremendous amount of my driving time with my foot in neither place, just coasting. I usually keep the foot hovering over the brake pedal for safety in case that child runs out chasing the ball.

This is a corollary of rule number 1, because the more you coast, the less you will need to brake. On your regular driving route, start figuring out where you can start coasting. For example, as you approach your driveway, where on the street can you take your foot of the accelerator in order to coast to a slow enough speed to turn into your house? This is good for security, too. It gives you a chance to check to see if you are being followed and to get your automatic gate or garage door—if you have one—open by the time you reach the driveway.

3. Watch your rev counter

Yes, look up occasionally for the ball and the child, but keep your eyes on the rev counter, or tachometer, too. The faster your engine turns, the more petrol it uses. On my automatic-transmission Honda Jazz, my goal is to never let my engine go above 2000 revolutions per minute at city speeds. (On the highway, it goes well above that; this rule applies to slow driving only.) Unless I must accelerate from a dead stop up a steep hill, patient driving will keep it below that figure. Two-thousand is not a general rule; you may need to find a different figure for your car.

On a manual transmission vehicle, there are two ways to keep revs down. One is to go easy on the accelerator. Watching the rev counter is a tool to teach gentle acceleration. The other is to shift sooner. Most people shift way too late. This not only increases fuel consumption, it shortens the lifespan of the clutch. As long as the car doesn’t buck, shudder or stall, you haven’t shifted too early. The optimum point of fuel consumption is the slowest speed at which you comfortably drive in the highest gear. When the revs are low, the car does lose some of its ability to quickly accelerate. But if fast acceleration is your main goal, you might as well stop reading this list.

4. In town, windows down

AA South Africa’s list has two somewhat contradictory pieces of advice. One tip says to turn off the air conditioner; another says to keep the windows up. That’s fine in the winter, but passing out from heat stroke in summer is not good for road safety.

A commonly repeated piece of advice is that air conditioning uses less fuel than rolling down windows. I think this is overly simplistic. The advice is based on the fact that rolling down windows reduces the wind resistance of a car. But wind resistance increases by the square of the speed. So when driving 120 kph on the highway, wind resistance is a huge factor in fuel consumption. (This also explains why reducing your highway speed moderately can greatly reduce your consumption.) So the AC-is-better-than-open-windows advice probably does apply here. But driving with windows all the way down at that speed is so unpleasant that you are not likely to do it anyway.

Driving at an average urban speed of, say, 45 kph, creates about one-seventh the wind resistance that you get at highway speed. So if opening the windows keeps the car cool enough to avoid air conditioning, it will save petrol. This is especially true because air conditioning has a greater impact on fuel consumption in town driving. According to the French environmental agency, air conditioning increases fuel consumption on average by 16 percent in highway driving and by a tres grande 31 percent in town.

If you are driving in an unsafe area—e.g. South Africa—you can still lower your windows by a few centimetres. In fact this is said to make a window more difficult—but not impossible—to smash.

5. Ride the roller coaster

Cruise control has its place, but constant speed is overrated. A roller-coaster car speeds up as it heads downhill and slows down as it climbs again. Doing this, a roller-coaster car achieves fuel consumption of 0 litres per 100 kilometres. We should take this as a hint.

When driving in hilly territory, strive for constant pressure on the accelerator, not constant speed. On a steep downhill you may need no pressure on the accelerator at all, but let the car build speed toward the bottom of the hill. (I didn’t say exceed the speed limit; your traffic fine is your problem.) On the way up the hill, allow the car to slow very gradually. By the crest of the hill, you should be well under the speed limit in order to take advantage of the next downhill. In heavy traffic on roads without passing lanes, you may need to moderate your speed changes. Try not to give the car behind you an excuse to make a dangerous pass.

Cruise control can save fuel in flat territory, especially if your weak quadriceps cause your foot to increasing weigh down the accelerator.

6. Drive your spouse’s car

In the middle of 2006, my wife and I decided that we had to do something about rising petrol prices. (How we long for those prices now!) We came to the conclusion that it no longer made sense to have “her car” and “his car.” Since one vehicle—a Honda Jazz—used less petrol, whoever needed to drive farther would use that car.

As a result, our use of the larger car—a Honda Odyssey minivan—has dropped from about two-thirds of our kilometres traveled to just 37 percent, almost in half. Swapping cars on a daily basis requires a little bit of coordination and is a minor inconvenience, but the swap is saving us about 700 litres of petrol a year. That’s R7000 at current prices.

7. Change your clocks

We all know that hard acceleration increases fuel consumption. Some tests have found that hurrying away from a dead stop causes a car to burn more than 30 percent more fuel. But when we’re running late, good intentions go flying out the tailpipe, and we press the pedal to the metal.

A lot of people find that they can trick themselves into leaving home or the office on time by setting their clocks five minutes fast. If you’re easily fooled, do it. Don’t set the clock ahead in your car, however. That way, you will see that you have plenty of time when you get behind the wheel. And a relaxed driver is a fuel efficient driver.

8. Know your numbers

Your chances of losing weight if you never step onto a scale are, well, slim. Equally, if you want to save petrol, it helps to know your numbers. Nissan has calculated that having a fuel-efficiency gauge on a car leads to a 10 percent reduction in fuel consumption. If you have such a gauge on your car, keep your eye on it when you’re not watching the tachometer or the kid chasing the ball. Reset it regularly so that you can monitor changes. It will encourage good habits. You can even fill up boring hours driving across the Karoo by tracking the differences in fuel efficiency with or without the air conditioner and at different driving speeds.

If you don’t have a gauge, reset your trip odometer every time you fill up and do a quick calculation. Litres per 100 km, the preferred metric, is quite simple to calculate in your head. Divide the number of kilometres driven by 100, knocking off two zeros. Then divide that number into the number of litres to fill your tank. So 500 kms and 40 litres becomes 40 divided by 5, resulting in 8 litres per 100 kilometres. Better yet, keep track of this information on a log book or spreadsheet, so that you can spot trends and changes.

9. Rearrange your “To Do” list

I brazenly stole this idea from David Allen, author of Getting Things Done. Allen’s goal is to improve personal efficiency, but this tip can boost fuel efficiency, too. He suggests that you organize your “To Do” list according to the place where you must get the task done. Phone calls you need to make go on one sublist for you to accomplish when you are at the phone, email tasks on another for when you are in your email software, and home repairs on yet another sublist to look at when you are in your house.

More important for your petrol consumption, errands are organized according to where you must drive to accomplish them. My “To Do” list has a heading for the East Rand, Downtown Johannesburg, Randburg, and a few other places closer to home. If a task can wait a week or two, I’m likely to find more errands in the same part of town. By consolidating a few trips into one, I’m not only “Getting Things Done;” I’m saving petrol.

10. Drive farther . . .

. . . but less frequently. A cold engine uses a lot more petrol, and emits a lot more pollutants. One study showed that in the first kilometre of driving on a zero-degree day, a car was using nearly double the petrol it consumed on the fourth kilometre. Even on a warm day, fuel efficiency in the first kilometre was 47 percent worse than in the fourth. And catalytic converters are nearly useless at cleaning up exhaust pollutants until they heat up.

So look for ways to cut down on short trips, by walking, cycling or consolidating several trips into one. (Using your reorganized “To Do” list, of course.) When you must make several stops, drive to the farthest errand first. As you work you way home, your engine should retain enough heat from the first leg to carry you through the rest of your short drives.