04 March 2008

How to save on fuel hikes

We love cars. We don’t love petrol price hikes or accidents or pollution or other drivers, but we love our cars. These fuel-saving tips are for those still hopelessly smitten.

We love cars. We don’t love petrol price hikes or accidents or pollution or other drivers, but we love our cars. These fuel-saving tips are for those still hopelessly smitten.

We know our relationship with the automobile is dysfunctional but we’re just not ready to end it.

So this article isn’t going to enthuse about ride-sharing or commuter cycling. Let’s assume you have no intention of driving less, but you would like to hear about how you can use less fuel doing it – and hey, if you can reduce your pollution output and make driving less of an unhealthy exercise all round, why not? Here’s how:

Don't go too fast
High speeds result in greater emissions, and of course they increase the risk of injury and death by road accident. You can improve your fuel mileage by about 15% by reducing your speed from over 100km/hr to under 90km/hr.

Fast driving includes “aggressive” driving: stomping on the pedals, which causes “jackrabbit” acceleration or screeching to a halt. Aggressive driving lowers your mileage by 33% on the highway and 5% around town. So keep it smooth.

If your car has an overdrive or cruise gear, make use of it as soon as your speed is high enough to help improve mileage.

Don’t go too slow
By this I mean avoiding situations where you’ll have to do a lot of bumper-to-bumper stop-start crawl-driving, as happens during rush hour and in congested areas. This really amps up the air pollution, and puts you right in the middle of it, often for long periods. Studies show that drivers (even with windows up and the aircon on) are exposed to levels of motor vehicle fumes just as bad as pedestrians are.

Avoid idling. Idling for even a few minutes burns more fuel than it takes to restart the engine. So rather turn off your engine instead of running-in-place, as can happen when waiting in lines or picking up passengers. This is particularly important to remember at school venues, where a lot of cars hover around at the same time to fetch or deliver kids.

Stay tuned
Keep your car well maintained, including the air conditioning system and wheel alignment. Just keeping the tyres properly inflated should give you more than 3% better fuel mileage, and longer tyre life.

It’s also good practice to monitor how much you're spending on fuel per km, say over a month. A loss in fuel economy usually points to an increase in vehicle emissions.

Fill up, not over
Instead of waiting till the needle’s on the red (or off the red, like I do), fill up regularly at times that are least likely to add to overall air pollution.

In other words, avoid filling up on smog-heavy days at rush hour. Rather fill up after dark and after rush-hour in the warmer months, to help prevent pollutants reacting with sunlight and becoming ground-level ozone (the 'bad' ozone, a major component of smog). Don't overfill your petrol tank, and make sure the cap fits properly – both of which will help prevent petrol spills and vaporisation of pollutants.

Open a window
Using the car's air conditioner increases load on the engine, which can increase emissions and decrease fuel economy. So do your best not to use it except when it's really stinking hot.

Try opening the air vents to cool the car's interior. It's actually recommended as a basic health tip to keep air flowing in from outdoors (even polluted city air is better than not) to dilute the inevitable backflow of exhaust, and specifically of poisonous carbon monoxide gas, from the engine. You can open the window too, of course, but this increases drag and reduces mileage.

Also, park in the shade when possible and use windscreen shades to keep the vehicle cooler.

Travel light
Clean out all the unnecessary clutter you may be carrying around in (or on) the vehicle. The heavier the vehicle, the more fuel needed to move it.

If you have to lug stuff, though, it's better to carry it inside than on top, as the latter increases wind resistance and thus fuel consumption. Also, if you’re not actually using your roof rack, it’s better to take it off – it too increases wind drag.

Plan your car driving around town so that you do fewer long trips rather than more short ones. If you do a lot of short runs, your exhaust system doesn’t warm up enough to function optimally, and your vehicle emits more pollution.

- Olivia Rose-Innes, EnviroHealth Expert, Health24, updated March 2008



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