The problems

For many people, public and professional alike, the major transport problem is ever-worsening traffic congestion leading to eventual gridlock. In 1999 John Prescott, the then deputy prime minister responsible for transport policy, began the Foreword to Breaking the Logjam, the government’s public consultation document on congestion, with:

Everybody hates traffic jams. They cost time and money. They pump out pollution. They take the pleasure out of driving. ¹

He ended with:

On recent trends, traffic is due to grow massively in the next 20 years. If we don’t act now, we will be heading for gridlock.

Prescott was restating a long-held view. As early as 1853 William Malins wrote:

It must be obvious that the constantly accumulating number of omnibuses, wagons and conveyances of all sorts will, if it continues for two or three years, render London insupportable for the purposes of business, recreation and all ordinary transit from place to place. ²

Almost 100 years later the London and Home Counties Traffic Advisory Committee reported:

Saturation point has been reached … traffic has outgrown the capacity of the streets. ³

This widespread view of congestion is a package of interrelated ideas:

Roads have a finite capacity – if the actual volume of traffic is below the capacity of a road then congestion will be kept at bay but, if greater, congested queues will form as traffic struggles through bottlenecks.

Such congestion is costly and undesirable.

The delays have become worse over the years and will get still worse as the volume of traffic continues to increase.

The worsening congestion will eventually lead to a complete gridlocked standstill.

The word ‘gridlock’ first appeared in the United States in the 1970s to describe heavy congested gridiron roads. If a queue at one junction tails back to the preceding one it will precipitate queues on the entry roads which will then tail back to other nearby junctions until all the roads and junctions within a series of gridiron blocks are locked solid. Gridlock is now more generally used to mean any dense, almost stationary, traffic.