Benefits of computer traffic control

Press, Volume CXI, Issue 32525, 8 February 1971, Page 2

Benefits of computer traffic control

(From GARRY ARTHUR, London correspondent of "The Press")

LONDON, Feb. 7. On the roof of the Hyde Park Hotel crouches a television camera whose unblinking eye is focused on one of London’s busiest intersections. What it sees—and what seven other cameras see—is relayed back to New Scotland Yard and quickly digested by two very expensive computers. They analyse the information, together with facts

coming to them from roadlevel vehicle detectors, then act upon it. If a queue is building, or the intersection is choked with cars, the computers choose a suitable prearranged traffic-control programme and instruct al) the traffic lights in the area to switch to red or green accordingly. The area affected is a 6|-square-mile section of inner ’London, whose, traffic has been controlled by the computers from the last two years —without being noticed by the motorists, except for the odd grunt of surprise at a smooth ride into town. FEWER ACCIDENTS Next month the experimental scheme will be handed over by the Ministry of Transport to the Greater London Council, which will no doubt be very grateful—for the West London area traffic control experiment has speeded traffic and reduced accidents at a time when other areas all around it were getting ever more snarled and more dangerous. ■ So successful has the experiment been that the Govemment has now authorised the Ministry of Transport to make cash grants to other cities wishing to install similar computer systems of traffic control. Contracts have been let for extending the system in London—ultimately to include the whole city. It is a long way off, but the Ministry is trying to make sure that those cities which install computer control use compatible systems so that they can be linked as the cities grow towards each other. MANY GAINS Several parties of New Zealand and Australian traffic engineers have been among the stream of experts visiting the control centre at New Scotland Yard. Among the benefits described to them ' are the 18 per cent fall in personal injury accidents I from the number ordinarily | "expected” compared with a 4.3 per cent rise in a control area, a 3 per cent drop in fatal or serious casualties, and a 2 per cent drop in pedestrian accidents—all in spite of an increase in the speed of traffic. Computer control has resulted in 345 fewer accidents

in the area in a year which (at the average cost of $lBBO an accident) represents $650,000. It cost about slm to install the two computers, which control 150 miles of streets in an area which includes the main route between London and Heathrow Airport, the Earls Court and Olympia exhibition halls, Chelsea and Fulham soccer grounds, and the busy shopping areas of Knightsbridge and Kensington High Street. FASTER RUNS The average journey time has been reduced 9.2 per cent —in spite of a 15 per cent increase in traffic—and delays at signals have been cut 18-5 per cent. Another benefit has been the freeing of 20 policemen from traffic control duties. The estimated total saving to the community is nearly ssm a year. Such savings—in time, money and life-and-limb—are seen as strong justification for spending more millions to install computer control of traffic elsewhere in Britain. Ministry of Transport engineers say that the system is justified for a city with a minimum of 30 sets of traffic signals at a density of six to the square mile, or with traffic routes where traffic signals are spaced more closely than six to the mile. They estimate the cost at $lO,OOO for each set of signals controlled—about $600,000 for the minimum-sized city for which the system is justified.

OTHER CITIES As well as Greater London, the cities of Liverpool, Leicester, Coventry and Nottingham are definitely going ahead with computercontrolled systems. Several others are looking at it. The West London experiment is the first trial system in the world to combine computer control of fully vehicle-actuated traffic signals with closed-circuit television surveillance at critical points. The computers select signalling programmes as they "see fit” according to the information they receive from prieumatie pads and induction loops in the roads. But if a situation gets so bad

that it stumps them, they ring an alarm bell and the operators can bring their superior brain power to bear and intervene manually. They can also override the computers' plan and rush an ambulance or fire engine through. POLICE USE Although the television cameras proved valuable in the early stages of the experiment, engineers say that they are not now needed for

the system to work efficiently. But the police have different ideas. Not only do the cameras give a clear view of a busy intersection—they can also pan and zoom in on a specific detail. Scotland Yard finds them useful for spotting accidents, illegal parking, get-away cars and hijacked lorries, and is insisting that more than 30 cameras be included in the first phase of the London extension to the system.