Friday, 6 July 2012

Blethers - Speed limiters


I’m no fan of speed limiters, but there are insidious elements of the community out there keen to see them being introduced.

At the moment heavy trucks have such devices fitted, hence the bunching that we often see on Motorways when one 56 mph governed truck tries to pass another doing 56 mph. Following motorists are often puzzled by the need for such a manoeuvre and then frustrated at the delay.

One of the reasons is that for reasons of fuel economy some truck fleets have a lower limit, say 55, or 54 mph, so there is a speed differential albeit small.

Another reason is that a heavier truck with a bigger engine will gain a bit more momentum on a downhill stretch so that it can use its muscle to crawl past the truck in front on the next incline.

If more vehicles are fitted with compulsory speed limiters then we will have more instances of bunching.

So the news that the Government is still considering plans to introduce an 80 mph speed limit for certain sections of certain Motorways is to be welcomed, BUT, there are calls for vans to have 70 mph speed limiters fitted.

A spokesman for the Freight Transport Association's Van Excellence Governance Group has stated: “A van travelling at 80 mph will be using significantly more fuel than one at 70. You don’t need a calculator to work out that at over £7 per gallon, that's just burning money. Without exception manufacturers can easily limit the top speed of their vans. So the question is, why don't they make limitation the default standard or at the very least a no-cost option?"

In other words, ‘big brother’ wants to interfere in our personal liberty, again.

For a start, what defines a van? Some vans are taxed privately, some commercially, while some have tachographs and others don’t. Some have been converted into minibuses and caravans while vehicle manufacturers have been known to build minibus versions of vans by adding windows and installing seats. Take the new Nissan NV200 and Ford Transit Custom for instance, not to mention the VW Transporter Kombi and Mercedes-Benz Vito Dual-liner.

And how would ‘crew vans’ be categorised? They have five, six or seven seats in most cases and a ‘boot’ on the back, and if you take all the removable seats out of a Peugeot Tepee, you have a van with windows and carpets.

Another thing, vans already have different speed limits from trucks and cars, so why the need for a compulsory speed limiter? Not a lot of people know this, but vans up to 7.5 tonnes GVW are restricted to 50 mph on single carriageways (car limit is 60 mph) and 60 mph on dual carriageways (cars 70) despite what the speed limit signs show. But then again car-derived vans up to 2 tonnes are not.

And why don’t I like speed limiters? Because it adds another degree of complexity to machines which are controlled by human beings. Apart from the issues of complexity and reliability of such mechanical devices, the biggest uncertainty is the capability, knowledge and experience of the physiological specimen in the driving seat.

All it takes is one ill-judged attempt at an overtaking manoeuvre in a speed limited vehicle, and the result could be anything from a hole in the hedge to a box in the Crem.

If they want to introduce speed limiters, why not start with cars, and see what sort of uproar that would create.

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