Monday, April 16, 2018

Getting the New Zealand road toll down to ZERO

By Andrew Atkin.

Yes, it can be done. But there is only one (realistic) way to do it.

Well amazingly, the Green party has come up with a policy proposal that I might agree with. As I understand, they are thinking about reducing the New Zealand highway speed limit to 70 km/h.

However, there is no way the 70 km/h proposal can be implemented until cars are driverless, for political reasons alone. The public would surely, otherwise, never accept it.

First, let's look at the safety advantage of travelling at 70 instead of 100 km/h. The braking distance at 70 is half that of 100, and if a 'freak' collision does occur it will happen with only a small fraction of the impact-force that it would be at higher speeds. With anti-collision technology provided by now-developed driverless systems, the chances of an injury causing death on New Zealand's roads would be virtually zero. Even significant injuries would be all but unheard of.

So getting the road toll down to virtually zero per-year, is not unreasonable. We can do it. But again the problem is getting drivers to accept travelling 30% slower which would increase their travel times by about 15% (Note. Reducing top speeds does not proportionally reduce average speeds, due to cornering and travelling through towns, etc).

The trick is to provide a proposal on reducing the top speed that the public can accept. Well, this is where the advantages of driverless Uber-style transport comes in. Let me create a scenario to give you the picture.

You live in Wellington and want to spend the weekend in Auckland. So, you order up a bed-car designed for sleeping for long trips, on Friday night. When your car gets to your door at 8 pm, it has a pre-ordered meal waiting for you included. You get in, start eating dinner, and watch the movie on the screen or work on your computer. At 10 pm you get tired and lie back and go to sleep, using your personal duvet and pillow, on what is literally a bed base in the car.

You wake up in Auckland at 6 am the next day, Saturday, without the sore neck. Your top travel speed was 70 km/h and your average speed was ~65 km/h.

What you would also notice, is that the car ride was unusually smooth. This is because the car has electronically controlled suspension that provides some active lean into the corners, and has an explicit map that allows it to smoothly avoid significant bumps on the road.

Now this is the point. Do we really need to travel at dangerous speeds when car-time is no longer dead time?

I would argue we don't. In fact car-time could be valued as it gives people more of their own space where they won't be directly disturbed. And the increase in travel times will not be drastic, at about 15%, if we reduce the top speed to 70 km/h.

And finally, there is always the possibility of building new roads that safely specialise to faster operation in the future. Maybe operating at 150 km/h with roads that have heavy super-elevation, for those who want to pay for this.


Let me list some other advantages of reducing highway speeds to 70 km/h.

-Approximately 60 - 70% reduction in energy consumption, from reducing aerodynamic drag and braking losses.

-Great reduction in road maintenance.

-Far more economical driverless freight operation.

-Major reduction in vehicle maintenance.

-Huge increase in road capacity via close platooning, which requires constant road speeds (not slowing for corners) to work well. (Note, driverless cars can be compartmentalised for privacy in car-pooling, which should be popular. This also can increase road capacity dramatically).

-Good for tourists, for where the trip is the destination.