A Congestion Charge for York

A locally administered scheme could not be based on tracking every individual vehicle that might visit the city. It would have to adopt a zoning approach by levelling charges at points or areas on the road network, as occurs with the London Congestion Charge. Like the London system, it would most effectively use numberplate recognition systems at chosen points on the road network. This technology is well established, already in use in the national Trafficmaster system(1) of over 7,000 camera monitoring speeds on motorways and trunk roads, and closer to home in the Stonebow rising bollard.

This system has the virtue of collecting only the minimum amount of data necessary using the minimum level of technology. The car registration number database is already in existence and widely available(3), for example by petrol stations, who commonly use it to identify motorists who drive off without paying.

In 1999 and 2000, a series of studies(4) was carried out by academics at Cambridge University on the practicalities of road charging in several historic towns in the UK, including York. These used computer modelling to simulate the behaviour of motorists under various regimes of road charging, and showed the probable effects on congestion and pollution.

The studies examined the possibility of creating cordons which drivers pay to cross during peak hours. By looking at what journeys took place in York and the congestion and pollution caused by them, the researchers determined the cost of the ‘average journey’ taking place in the city at a particular time. This was then translated into a price to be charged at a cordon.

After several studies by the same team, the results seemed to point to the most beneficial solution being the use of two cordons - a city-centre cordon covering the most common destinations, and a city-wide cordon to make York less a destination for car traffic. This model was chosen for the Edinburgh scheme mentioned earlier(5), but York is where the results looked most promising(6).

Notes and References

The Trafficmaster system monitors speed information on trunk roads by detecting numberplates passing a camera array. Camera arrays are set up at intervals and the time taken for a given numberplate to travel between two sites gives an indication of the speed of flow. Numberplate data is not retained, after measurements have been taken, according to their website. Another similar system was used by the British army to monitor traffic in Northern Ireland, the 'Vengeful' system mentioned in Tony Geraghty's book The Irish War.

It's therefore unsuprising to read, in articles in The Indepedent and The Sunday Times, that a nationwide ANPR system is shortly to be introduced all over the UK. Insufficient information is in the public domain on these plans, which of course raise many new privacy and data security questions.

Like the Trafficmaster system, an ANPR (Automatic Number Plate Recognition)-based system could be designed so that the only data retained relates to drivers who have not paid the charge. If a registration number is detected that relates to a charge having paid, no data is logged on its movements.

Developments in public transport monitoring across the city, including the construction of a 'wireless mesh' of city-wide data communications, mean that the implementation costs of the system would be significantly cheaper than in previous schemes.

In, it would seem, contravention of Data Protection rules, according to the Daily Mail (27th November 2005). We can probably expect to see more exemptions on data protection on the books soon.

The studies by a team lead by Prof. David Newbery and Dr. Georgina Santos at the Department for Applied Economics at Cambridge University, produced the following papers-

Each of these studies used the SATURN (Simulation and Assignment of Traffic to Urban Road Networks) modelling system to evaluate the effect of differing economic and time pressures on drivers. At one point, these were all available on the web for free.

See note 4 on page 1.

One of the major problems with congestion charging is determining how much to charge. Any attempt at distributing costs through this kind of tolling will have to take into account the effect of the toll on the people travelling - principally, drivers will divert to avoid being charged, meaning that they are not paying the full costs of their trips. The willingness of a group of people to change their habits in economics is called 'elasticity of demand'. To estimate this quantity is to predict how people will behave when prices go up or down. The study Double Cordons in Urban Areas to Increase Social Welfare (Santos, 2002) shows that the effect of different levels of elasticity of demand makes actually very little difference in York. This is mainly due to the structure of the road network, which provides people with few alternative routes.

This finding gives us confidence that the effects of congestion charging in York would be more predictable than in many cities.