If roads were like arteries

Alan Clawley comments on the ever-increasing amount of road traffic

Road engineers like to tell us that roads are like human arteries and traffic is like blood. It’s a useful analogy but one that hasn’t been seriously applied to reality.

The human circulatory sy.stem is beautifully designed to transport a fixed quantity of fluid around the body picking up oxygen and disposing of waste products on the way. The body’s sophisticated control mechanisms make sure that no more and no less than the regulation eight pints is maintained in the system. The body’s internal pump, the heart, keeps the fluid circulating efficiently round a one-way system. The system only goes wrong when there is a leak in the pipes, they get clogged up by fatty deposits caused by a bad diet, or the pump breaks down due to wear and tear. If our road system was designed along these lines our traffic problems would be over.

Tarmac roads were invented because wheels got stuck in ruts and potholes. If everywhere was bedrock there would have been no need to invent paved roads. Vehicles could have gone where they liked provided they didn’t bump into each other, hence the need for the ‘rule of the road’. Roads cost money to build so they had to be confined to a narrow corridor between a limited number of places even though everyone wants to go everywhere.

Hence the notion of the arterial road. The only limit to the size of the road network is how much we the taxpayers can afford and how much land we want to leave for houses, shops, farms and factories. This is a constant dilemma for government. There’s an incessant demand for more roads to be built, presumably to reduce traffic congestion, but as more roads are built the cost of maintaining them increases. As soon as a new road is opened it fills to capacity, leading to demands for more roads.

Meanwhile cars – blood corpuscles in the analogy – are produced ad infinitum as long as people can afford to buy and run them. Government don’t want to dictate how many cars the present road system can carry or how many the country as a whole can live with even though they know it’s already too many. Levying charges or pedestrianising a few streets is as far as they will go. The result is chronic road congestion – thrombosis, clogged arteries.

It’s obvious that the problem can’t be solved by building more roads. The human body doesn’t create more and wider arteries if for some reason it was called on to handle a greater volume of blood. The evidence of the failure of road-based solutions – new roads, road widening, road improvements, hamburger roundabouts and what have you – is all around. In 1980 Small Heath was promised a (heart?) by-pass that would remove traffic from the old Coventry Road and allow it to be given over to pedestrians. Today the ‘Cov’ is worse than ever (see picture). Likewise, the M6 Toll, once optimistically named the Northern Relief Road doesn’t prevent jams on the M6 and congestion still persists even when the hard shoulder is used.

Treating a road like an artery only works when a fixed number of vehicles are allowed to use it. Motorists will not behave like blood corpuscles and be told when and where they can drive their cars. Unlike passengers on public transport they cling to the illusion that they are free agents. But that illusion can be broken as it has been in London, where motorists have come to accept the limitation on their freedom to enter the central Congestion Zone. Rather than pay the Charge they leave their cars at home and use buses, tubes, trains and bikes instead.

Pic: (c) the author.