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27 April 2006: Truckers

A

s is my want, I’ll match speed with a heavy goods vehicle on the motorway (something I’ve imaginatively called “HGV Pace” heh), hit the cruise control button and while my way en route to the office. I’m on the A64 and the A1 for approximately twenty miles and the difference between a genuine fifty five and a genuine seventy miles per hour is around five minutes. So sure it is quicker to get to work if I drive at seventy, but those five minutes are easily made or lost at either city end. On a “lucky” commute where I meet green lights and good traffic flow, the trip can take me forty minutes. On an unlucky trip with every light a red and every junction busy, it’ll take me closer to an hour. Given that context, yeah I’ll adopt the slower cruise, it makes so little difference to how long it takes me to get to work.

But I digress.

The point of this entry is to protest at the stupidity occasionally illustrated by the professional knights of the road, the truckers.

Trucks are limited in the United Kingdom, typically to somewhere between fifty four to fifty six miles per hour. A fully laden truck will usually pick up speed when descending a gradient and slow down on the way up. In most cases the speed difference is just a few miles per hour, which isn’t a problem to deal with this, just use the ACCEL and DECEL buttons on the cruise control system. Where the problem occurs is when one truck’s limiter is at 54½ miles per hour and another is at 55¼ miles per hour. On the flat the quicker truck will overtake over some great distance. Throw in a hill and the slower truck may have a higher power to weight ratio and be able to maintain a higher speed going up the gradient, whereas the quicker truck may be unable to continue the overtake on the way down.

The stretch of A1 between the A64 and the M62 has a few gradients. They’re not exactly steep, but steep enough for one to notice the ebb and flow of trucks if driving along using the cruise control system. And I’ve witnessed two trucks battling it out over the entire twelve miles of motorway, neither willing to let the other pass.

What gives? Talk to a trucker and he’ll tell you that this is an unusual case. It is, usually the slower trucker gives ground. But why overtake if the speed advantage you have is just one or two miles per hour?

In some cases, the slightly quicker truck has a material advantage when ascending gradients, presumably because this particular truck has greater power. But sometimes the opposite is true: the slower truck on the flat is better able to maintain a constant speed. What then happens is that on the flat, one truck overtakes but as soon as you reach a gradient, the other one overtakes. Then on the flat the original truck overtakes again. Since there’s such a small speed differential it’s possible for the two battling trucks to take something like forty miles before one of them goes their separate way.

The excuse is that for a long haul trip, that one or two miles per hour can make a big difference. I don’t buy it. Let us suppose we have a six hundred mile trip. At fifty four miles per hour miles per hour it will take us five hours, thirty three minutes. At fifty five miles per hour we save six minutes.

Six minutes? Six minutes over five and a half hours... That’s not worth it, surely? I don’t believe most of the nonsense spouted about how these minutes can make a material difference.