Minimising TED conflicts with speed limit

The tractor was travelling at a steady 50 kilometres an hour as I followed it for several hundred metres on a windy stretch of road.

When we got to a straight I indicated, put my foot down and pulled out to pass.

By the time I pulled back in I was doing more than 80 kph.

If you have to go more than 30 kilometres faster to pass someone travelling at 50 kph, how can you pass someone driving faster but still under 100 kph without exceeding the speed limit?

If you want to minimise the time exposed to danger – TED, when you’re on the right hand side of the road – you can’t.

Rodney Hide has worked it out:

In good driving conditions we are advised to apply the “two-second rule”. At 90km/h that’s 50m. So you pull out 50m behind a truck and trailer, the truck and trailer is 20m long and you pull in once safely 50m past. You have to make 120m to pass safely.

If the truck is doing 90km/h and you stick to 100km/h it takes 43 seconds to gain that 120m.

At 100km/h you will have travelled 1.2km. You must allow for a car coming towards you at 100km/h. To pass safely you need 2.4km of clear road.

That doesn’t happen often.

So you wait for a passing lane. The traffic behind the truck and trailer builds up. Finally you get to a passing lane. The front cars take off – at 100km/h. I drove Auckland to Queenstown these holidays and typically only the first two cars would make it past.

I would then watch in horror as a couple of frustrated drivers would try to pass the line of cars and the truck and trailer without the benefit of a passing lane or a clear road. It was frightening. And predictable. . .

What’s also predictable is that the slow vehicle will often speed up at a passing lane making it even more difficult to pass.

I am no speedster. I am never in a hurry. I am content to drive at the speed of the traffic, whether its 90km/h or 100km/h. In more than 40 years I have only had two speeding tickets.

But if I must pass, I hit the gas hard. I want to get past as quickly as I can to get back on the correct side of the road as soon as I can. I minimise what is called the “time exposed to danger”. I typically pass at 120km/h. . .

 A friend was clocked doing about 120 kph as he passed a large truck. The traffic officer eventually, albeit reluctantly, accepted his explanation that passing quickly by reducing the TED was safer than passing slowly and that not passing at all was impractical.

A few kilometres slower or faster doesn’t make much difference to the time of a long journey. But if the second vehicle doesn’t pass the first then a third will catch them up and soon there will be a long queue which will inevitably catch up to an even slower vehicle.

Another friend was in a long line of slow traffic when a police car passed with siren and flashing lights going and pulled up the first car that had been holding everyone else up.

That’s two instances of good policing.

The first recognised that minimising TED can be safer even if it means temporarily exceeding 100 kph.

The second recognised that going too slowly without letting other vehicles pass can also be dangerous.



8 Responses to Minimising TED conflicts with speed limit

  1. But but but speed kills…

    I always say what about the auto-bahn


  2. Oh yeah I’m not just good looks

    I do have an actual workable plan to improve NZ’s roads which involves training the Army to build the State Highways

    My plan is a bit rough and ready and needs some fine tuning and a little polish – just like me


  3. I seen on a previous post you were talking about cycle trails…

    I would start by building a Nation wide cycle way to boost local and international tourism. You also gotta crawl before you walk and Rome wasn’t built in a day…

    Why??? Because I am also a cowboy…

    I have over a decade of experience in heavy haulage with no serious accidents up to triple roadtrains. I know cyclists and trucks don’t mix!!!

    Cars and trucks don’t really mix either!!!

    For the record I am also a bona fide lifesaver and heartbreaker…

    A little off topic that last one I know but I don’t run my mouth without good reason


  4. Richard says:

    One of the real problems is the speed limits are not being enforced or obeyed

    Large trucks 90kph
    Milk trucks are the worst – sitting on 100kph but never over – impossible to pass I heard long ago that there is an informal exemption from the the authorities for milk – but other trucks are the same

    Light vehicles towing trailers 90kph – most drivers of these exceed this limit

    But trying to pass a vehicle going at 90 kph, you are bound to exceed the 100kph limit


  5. “One of the real problems is the speed limits are not being enforced or obeyed”

    Wrong Richard

    Just got back from travelling our State “Highways”

    They were crawling with speed enforcement officers

    What we need is a dual lane highway North to South, East to West


  6. If you or anyone has a better idea on how to get the State Highways built than me then I would like to hear it


  7. Just like I thought. Not one of ya’s in the whole country has got a better idea than me


Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

%d bloggers like this: