Overtaking, inevitably, often becomes necessary in normal motoring, and it rarely helps your fuel economy, although there are some situations when it actually can ñ such as when it lets you escape from being stuck behind a driver who stops at every roundabout and slows excessively for every slight bend in the road. But overtaking calls on extra engine power and strong acceleration to gain a significantly higher speed, which invariably uses extra fuel, and sometimes may also involve braking, with a further wastage of energy, and fuel, which we would want to avoid wherever possible. 

How then can we minimise, maybe even eliminate, the apparently unavoidable use of extra fuel involved in overtaking another vehicle? Here are some examples: Travelling directly behind a loaded HGV, cruising at 45 to 55mph, can be an acceptable cruising speed, but for the usual lack of forward vision and periods when the HGV in question has cause to seriously slow down. Lacking in power, it may take a frustratingly long time to accelerate back up to its cruising speed, and often creates tailbacks that tempt drivers into risky overtaking. At such speeds it is often difficult to overtake safely, particularly on an A-road with a 60mph limit, but there are opportunities. It’s often best done when you and the HGV are accelerating away after the HGV, and any vehicles stuck behind, have all slowed right down, or maybe even stopped. It might be after traffic lights, a bend, or following a roundabout, or any such similar situations. Given a clear road ahead, and with the low speeds involved, strong acceleration in the right gear will get you swiftly and safely past such a truck, or other slow-moving vehicle. Once past, you just ease off the accelerator to hit your chosen cruising speed, with no braking needed, and less fuel used than if you had slowly followed the HGV back to its chosen cruising speed, when overtaking would then again become very much harder. With the lower overtaking speeds involved, such opportunities do need grasping when they appear though, and you do need to keep a close eye on your mirror for other drivers behind with similar ideas.

Having spoken of using strong acceleration, the opposite tactic of using well-planned deceleration can also offer equally effective fuel-saving overtaking opportunities, and again they need grasping positively when they arrive. When you’re in the company of slower vehicles, particularly HGVs, on fast two-lane dual carriageways, the approach to the frequent roundabouts offers opportunities to overtake HGVs when they necessarily have to start slowing down much earlier than you. Holding your speed when they start to slow down gives you the opportunity to ease past them in the overtaking lane, obviously with care, and keeping a close eye out for other fast outer lane traffic. By looking well ahead, you may spot other times when, by even accelerating somewhat, you can create such an opportunity, if you can close up on and then slip past the HGV well before the roundabout. That’s so much better than finding yourself rapidly closing down on a slowing HGV, possibly even then needing hard braking, just as you approach the roundabout, and having to slow right down to as little as 10 to 15mph, with the significant loss of momentum. Most modern cars have the ability to negotiate roundabouts at much higher speeds than HGVs, and by taking or creating opportunities like these, you can execute safe overtaking without causing any problems for HGV drivers, as long as you give them plenty of space, make your intentions clear, and keep an acute awareness of other roundabout traffic. If your plans do turn sour, don’t ever attempt to overtake a large HGV, which may need to use two lanes for space, on the roundabout itself, but wait until it is clearly back in lane and, given space, slip past as you accelerate away, as described above. 

Economical driving is all about anticipation, conserving energy and maintaining steady, sensible, speeds. That involves escaping the fuel-wasting frustration of following slower vehicles, as we’ve described above, and not being pressurised into using risky and inefficient ways of overtaking them. Few things in motoring are more satisfying than executing such overtaking manoeuvres safely and skilfully, and you may find other situations where similar ìsmart overtakingî can save you fuel, and keep you safe, just as long as you use the right gear for the occasion.

Victor Harman