Everyone's gone speed-hump crazy /MOTORING

The handiest street atlas I have ever used landed on my desk for review the other day. The London Back Street Map is an easy-to-use guide to the capital's best rat-runs.

The maps are big and colourful, and clear enough to enable you to avoid main road traffic snarls while glancing at the page. Taxi drivers, or so the blurb says, were enlisted to help. I have been using the book for a few weeks now, and have shaved at least 10 minutes off my commute to work, and valuable time off other peak-hour journeys.

But while the book's publisher is doing its best to ease congestion and help motorists, most local authorities are doing the opposite. In particular, they have gone speed-hump crazy. In my particular bit of London, it is not only popular link roads whichare sprouting these mounds.

Increasingly, quiet traffic-free back streets are also being turned into motorised mogul fields.

The original intention of the speed-hump was clear enough: to reduce speeds on roads that had apparently become dangerous because of the rat-runners. Now, though, residents increasingly lobby their local authorities for speed-humps, not because of genuine safety fears (although that remains the excuse), but as a convenient way of making their own roads quieter. Of course, a quieter road is usually a safer road. But if all residents used this ruse, we would not have a road network. Where would it end? Why not put up road humps on all A- or B-roads that have housing (most do)?

When the humps go up, motorists are dissuaded from using public roads which you and I pay for. The result is that more traffic has to use the main roads which are usually just as residential as back streets. Overall, congestion gets worse. So does pollution.

Humps are a dubious way of slowing motorists. Most humps are impossible to drive over at the legal 30mph limit, let alone the 20mph speed advisable on residential streets. (What would happen if a driver destroyed his suspension hitting a hump while driving legally at 20mph or 30mph: would the local authority pay the bill?)

Speed-humps, particularly the big ones that now seem to be sprouting in my part of town, are dangerous for motorcyclists and cyclists - street-users rarely considered by road builders. Even at low speed, the humps give cyclists a nasty jolt, not unlike being kicked by a mule between the legs. Motorcyclists have to slow down to walking speed. Otherwise, they will be thrown off.

Goodness knows what long-term damage is being done to suspensions and tyres of cars. No doubt we have already seen fatal accidents caused by the accumulative mechanical damage inflicted by these so-called traffic calming measures.

Traffic calmers! They make drivers more agitated and force the traffic to speed up and then slow down (causing more pollution and mechanical noise, owing to the constant acceleration and deceleration). They encourage drivers to pay more attention to the actual road surface than to surrounding scenery, such as children playing nearby. And, daftest of all, they turn perfectly good roads into rollercoasters.

I cannot think of a single other public facility designed to make the user's task as onerous as possible - apart from a humped road. Besides, as the Government is poised to cut back on road building, surely it makes sense to optimise our existing road network?

An acquaintance of mine, an ambulance driver, is also waiting for the first death caused because he could not reach a house on a humped-road on time. It must have happened already, somewhere in the UK. Ditto the fire brigade and the police. At least the fire engines and ambulances can reach homes on humped roads, which is more than can be said for homes located on streets blighted by the previous generation traffic calmer: the width restrictor.

There are, of course, some quiet residential roads that are threatened at peak hour by rat-runners - just as there are main roads made more dangerous by speeding motorists. Rather than using speed-humps, the police should set up their radar traps and earn some revenue (a language the current police chiefs certainly understand). They will soon persuade the regular speeders either to slow down or go elsewhere. Alternatively - or as well - fit a Gatso camera box and a big warning sign. The Gatso box itselfis far cheaper than building a series of humps.

Speed-humps deter and hinder all motorists - whether they are law-abiding or not - from using roads that they have a perfect right to use. Finally, all residential roads should have a 20mph speed limit, which I have been urging for years.

I recommend the London Back Street Map. It even warns of those rat-runs that are humped. Please do not avoid these routes, though. The best way of removing the mounds is to give lobbying residents a share of their own medicine. Namely, to give them the hump.

The London Back Street Map, published by The Clever Map Company, £4.99.