Within a month of the start of the current Middle East conflict, oil jumped from about $70 to more than $100 a barrel. Here are some fuel-saving tips to help motorists counter the subsequent rise in fuel prices.
Modern cars are built to be efficient with fuel and lower emissions, but how you drive and how you look after your car can swing your fuel use by big margins. Smooth driving, the right tyres and wheel setup, and shedding unnecessary weight or drag all add up to real savings on the pumps, especially on South Africa’s long commutes and weekend trips.
Rolling resistance
At city speeds, cutting rolling resistance is key to saving fuel, and the quickest win is keeping your tyres at the correct pressure. Underinflated tyres increase rolling resistance, which can push fuel use up by as much as 10% to reach your chosen speed.
Tyre pressures are usually listed on the driver’s door frame or inside the fuel-filler flap; don’t use the number on the tyre wall. Only adjust pressures when the tyres are cold – or if they’re hot, let them cool for at least two hours. Pressures tend to rise by about 20 to 40 kPa as tyres warm up, so setting them hot means they’ll end up underinflated when you drive.
Check pressures monthly with your own gauge if you can; if not, check them when you refuel. Before a long trip, re-check all tyres, including the spare. Do not inflate beyond the recommended levels, as over-inflating reduces the contact patch and can affect steering and braking.
If wheels are out of alignment, tyres scrub sideways instead of rolling straight, which raises rolling resistance and can shave 1–2% (or more) off fuel economy. If the steering feels “off,” the car drifts on level ground, or tyres wear unevenly, get the wheel alignment checked and fixed. A small investment here often pays back in fuel savings and longer tyre life.
Reducing aerodynamic drag
Aerodynamic drag rises with speed squared and typically overtakes rolling resistance around 60–80 km/h, continuing to climb exponentially after that. In city driving, a roof rack or roof box is rarely needed and greatly increases wind resistance, while even an empty roof rack can noticeably raise fuel consumption at highway speeds.
Roof-mounted tents, bulky cargo boxes, or roof-mounted bicycles can push consumption up by 10% or more. SUVs often “need” the roof rack for style, but the rule is simple: remove it completely when not in regular use. Fitted longitudinal roof rails are fine, but if you add cross bars to mount bikes, kayaks, or a roof box, take them off when not in use. For pickups, an empty open load box is a major drag contributor, which can be reduced with a cover.
Driving habits in city traffic
Urban driving is where bad habits hurt fuel use the most. In stop-start traffic, aggressive accelerations from lights followed by harsh braking can boost fuel consumption by 20–30% compared with smooth, steady driving.
Aim for gentle acceleration with light to medium throttle to reach the needed speed, then lift off and coast as you approach a red light or stop street. An automatic gearbox will usually shift up quickly to keep engine load steady, helping keep fuel use down. Eco modes in many cars do similar things by softening throttle input. With a manual, try to upshift as the acceleration tapers in each gear. Don’t select neutral or press the clutch when coasting to a stop, as idling still uses fuel; engines burn far less fuel if you’re coasting with the engine at around 1,000 r/min and the throttle closed.
Some people claim blasting away at full throttle for short bursts and then lifting off saves fuel. The idea is that wide-open throttle lowers pumping losses, but in practice the engine’s ECU richens the mix at WOT to deliver power, not economy, so this usually ends up using more fuel.
Highway driving considerations
On open roads, the speed–fuel relationship is exponential. Drag grows with speed squared and makes up more than 75% of total resistance at around 120 km/h, so lowering cruising speed can save a lot of fuel. A reduction of about 10 km/h might save up to 10% in fuel, depending on the car.
Cruise control can help on flat or gently rolling sections by minimizing small speed fluctuations. But turn it off in heavier traffic; after you’ve slowed, some systems will accelerate back to the set speed more aggressively than needed. On hills, going a bit faster downhill can mean using less throttle to climb the next incline.
Other contributory factors
The air-conditioning (AC) always adds to fuel use, but its load on the engine is bigger in city driving than on the highway. When using AC, aim for moderate temperature settings and lower fan speeds. Park in the shade when possible; if that’s not an option, open the windows briefly at startup to vent hot air rather than relying on the AC to cool it. At highway speeds, keep windows closed, as the extra drag from open windows often outweighs the benefits of running the AC.
Remove golf bags or any heavy cargo from the boot when you don’t need them, since repeated acceleration with extra weight costs fuel. Regular servicing is important too—a dirty air filter, worn spark plugs, or old engine oil can trim efficiency by a few percentage points.
These measures will help drivers counter rising moving costs, but bigger savings can come from carpooling or lift clubs and careful trip planning to cut vehicle use. Of course, those planning a new car should consider electrified or hybrid options, as the payback period on a higher purchase price has just become shorter.
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