What’s safe and what’s legal are two different things, especially if you follow the rules for country overtaking.

A COUPLE OF WEEKS AGO I described something called the Australian Overtake – you know, where you attempt to overtake a car on the freeway and it takes forever as you’re doing 99.9km/h and they’re doing 99.1. That really struck a chord with people, and sparked other writers to vent about keeping left on freeways.

But confected outrage doesn’t help win the argument. Cold hard logic does, so let’s see why legal overtaking often isn’t safe.

The law says you must not exceed the speed limit when overtaking. It also sets a speed limit for each road. So let’s set the scene; we have a country road with a limit of 100km/h, along which there is a car travelling at 90km/h. We are travelling at 100km/h, and eventually catch the car in front.

The good advice from the government is to maintain a 3-second gap to the car in front. We’ll cut that gap to 2 seconds as we’re going to overtake. At 90km/h we travel 25 metres per second, so a 2-second gap see us 56m behind the car in front. Once past, we won’t pull in till we’re ahead – let’s say another two seconds, about another 56m. The length of the car is 5m, so our total overtake distance is 56 + 5 + 56m = 117m.

So we begin to overtake, doing 100km/h to the other car’s 90km/h. That’s a 10km/h speed difference, and we need to cover 117m. A speed of 10km/h is 2.8 metres a second (m/s), so to find the time taken to overtake it is:

117m / 2.8m/s = 42 seconds. During that time you’ll cover 1.2km.

And that’s at 10km/h. If the car in front does 95km/h and you do 100km/h to overtake, that’s 84 seconds, or 1 minute 24 seconds to overtake, during which you’ll cover 2.3km.

I’ve made some simplifications in the calculations, but they don’t change the central point – how do you feel about being on the wrong side of the road for over a full minute when overtaking?

Don’t believe me? Next time you’re on the freeway, start from 2 seconds behind someone, zero your trip meter, start counting the seconds, and stop when you’re 2 seconds ahead. It’s a surprisingly long time and distance. And that’s just for a car. A B-double truck is 25m long for example, so that’s about another 7 seconds on the wrong side of the road at 10km/h.

Now what about overtaking lanes? Two problems. First, they aren’t always available. Second, they tend to be 1km long, and as we’ve just proved, there’s not enough distance to get by a car doing 90 if you’re doing 100km/h and stick to the official guidance.

You could squeeze it a bit and start the manouvre later or cut in earlier – say cut it down to 1 second before and after- but that doesn’t solve the other problem which is that if a car is doing 90km/h on a moderately busy country road, it won’t be long before it has a tail of cars behind it, and then they all try to use the same overtaking lane.

Now some would say just wait for the right chance to get by. But the maths says unless your route involves an international-class aircraft runway then you won’t have the space to make the overtake. And even if there was a 1.2km space to overtake, you can’t easily see that far down the road so you need to start the overtake and just hope it works out. Really not seeing how that’s safe. And if there’s a car coming the other way, then it’d need to be at least 2.5km away when you start the overtake..you’ll need a long stretch of road and good eyes to see that far ahead.

What about simply waiting and not overtaking? That would be a favourite solution of people that don’t drive long distances in the country, but there’s three problems; fatigue, traffic jams and frustration. Fatigue first; last week I drove 550km to Mildura, and if I had to drop 10km/h off the speed my travel time would have increased from a bit over 6 hours to 7 hours, including stops. If it was 80km/h, then that’d be another 1.4 hours compared to the normal time.

How is spending more time being bored on an empty road safe when we all know fatigue is a problem? It’s not like driving well under the limit is some of sort de-stress effect.

Second, traffic jams. We’ve got our 90km/h car bimbling along, and behind it we now have 10 other cars traveling at 90. The lead car approaches a 60km/h zone and slows down to 60. It does that maybe 300m out from the 60km/h sign. That means the car behind it has to brake about 350m out from the sign. The car behind that one about 400m. Typically, each driver will brake that little bit harder than the car in front so it’s both a distance and speed problem. You get enough cars, and the entire traffic flow comes to a halt, something you can see every day when you commute on freeways – it’s called “sheer weight of traffic”. All this leads to frustration, and frustrated drivers are not safe drivers. And longer travel times for everybody. It could be avoided by overtaking to space the traffic out.

So that’s the problem, now what about the solution? How about this:

Allow a 20% speed limit increase when overtaking on single lane roads. That means you could do up to 120km/h for an overtake in 100 zone, which would bring your time and distance to pass a car doing 90km/h down to around 17 seconds and 580m, not 41 seconds and 1.2km – need to allow a bit of time to get up to 120 and back. This isn’t raising the speed limit to 120 – that’s another discussion – it’s just allowing people to get an overtake done quickly, and not focus on the speedo when they should be looking far, far ahead. Here’s a diagram of what it looks like:

Encourage a culture of “lift when being passed”. Just a slight easing off on the accelerator as a car goes by makes the overtake that much quicker, and therefore safer. Issue fines for those who do not lift; so we can have the happy situation of someone overtaking at 120km/h not being fined, while the car they are passing speeds up to 105km/h and does get a fine.

Just a slight easing off on the accelerator as a car goes by makes the overtake that much quicker, and therefore safer. Issue fines for those who do not lift; so we can have the happy situation of someone overtaking at 120km/h not being fined, while the car they are passing speeds up to 105km/h and does get a fine. Include country road overtaking and driving in the driving curriculum. Because it’s not there at the moment. Overtaking is really dangerous, yet it’s not properly taught. Maybe also chuck some fatigue management, basic car repair skills and long-distance navigation in there as well. And trailer towing. But that’s for another time.

The 20% speed increase is pretty much what everyone does worldwide anyway. The difference with Australia is that you are penalised for it. Look at the title photo – the white Kluger is there to collect speeding fines, yet it’s in an absolutely prime spot for safe overtaking.

Begging or yelling at people to keep left won’t work, because the whole road system is set up to encourage people to hog lanes. You can’t change human nature, but you can change the incentives that drive their behaviour and by constantly appealing to drivers authorities show they do not grasp this simple fact.

And yes, we’ve all seen idiot overtake moves. But you know what? Idiots are idiots regardless of the laws, and what about this – how about allowing the police to use their discretion? What’s safe is not necessarily legal, and what’s legal is not always safe. Those highly experienced highway patrol officers know the difference better than any of us. Sadly, they must use their rulebook not their intelligence.

So what do you reckon – should we be allowed to speed up to get overtakes done, or are you happy spending an eternity on the wrong side of the road or cruising well below your preferred speed in a train of other frustrated cars?

Do you speed up when being overtaken? Maybe you’re a fatburg..