Marian Pallister reports on a pilot

car-sharing scheme in Leeds, which aims to reduce the problem of urban congestion.

IF you are not a morning person, or if stressful days in the workplace leave you a little raw and edgy on the journey home, then the traffic scheme which Leeds is putting into operation today on one of its busiest approach roads may fill you with horror. The City Council is demanding that if you want to drive into the city centre quickly, you are going to have to be sociable.

The UK's first traffic lane dedicated to rush-hour car-sharing is aimed at reducing the number of vehicles going into the city centre, and at cutting the time it takes for drivers with two or more passengers to get there. It will be monitored with great interest because it has the potential to achieve cheaply and effectively what all city traffic supremos are aiming for, without leaving commuters high and dry.

It is a scheme we already know can work, because most of us dutifully abide by bus and green lane laws. According to an Edinburgh police inspector, only a few flout the rules intended to make the capital's traffic flow more freely, and if the example of Leeds were to be followed, on-the-spot fines of #20 or #200 if a case went to court would quickly make the motorist aware that the sign with the silhouette of a car bearing the legend ''2 +'' means exactly what it says.

Edinburgh City Council figures show that the average car heading into the city contains between 1.2 and 1.4 people, and Friends of the Earth research in Scotland finds that 75% of cars are run with only the driver in them. Dr Richard Dixon, head of Scottish FoE research, says: ''Even if you got just half of those people to share, you would have halved the number of cars coming into a city.''

The Leeds scheme is the first on an urban route in Europe, although Madrid has a similar project on a stretch of trunk road. In America, multiple occupancy routes have operated successfully for two decades. In fact, Dr Dixon says, they are so speedy that people cheat to drive in them, buying shop window mannequins to appear to qualify. Leeds City Council has already decided that a body in the back of a hearse doesn't count as a passenger. The jury is still out on how to deal with a pregnant woman who claims to be eating and driving for two.

These are negative aspects to the scheme, but environmentalists have high hopes. Dr Dixon says: ''One of the main problems in cities is that in the mornings and evenings traffic is clogged by cars. Single occupancy cars are a good area to tackle and every city in Scotland should look to see if there is a route which would benefit.'' He suggests the route into Edinburgh from the West and the Forth road bridge, the M8 going into Glasgow, and the approaches to Aberdeen. Shared lanes with buses could be an answer if there isn't room enough for a specially designated lane. Dr George Hazel, director of city development in Edinburgh, doesn't think so, however. A similar scheme was considered but discarded because the city wanted to give priority to public transport and it was felt more than one designated lane could be confusing.

The idea might find more favour in the West. The Keep Glasgow Moving document drawn up by Glasgow City Council road and transport experts is now out to public consultation, and roads and transport convener Walter MacLellan has said that Glasgow has one of Europe's highest rates of new car ownership. To accommodate them all would mean the destruction of the city. He is already targeting people who drive their cars to work, park them all day and drive home, and wants more park and ride schemes. The public reaction has been that public transport cannot, in its present form, replace the convenience of the car, and encouraging people to cycle has limited appeal.

Dr Dixon warns of cultural differences. In Amsterdam, for instance, there are free bikes for universal use which can be ridden anywhere in the city then stacked in a rack. When the idea was introduced to the UK all the bikes were stolen and stripped for spare parts.

High-occupancy car lanes will appeal if they really do prove to be fast, if the policing is thorough enough to prove it costs dearly to cheat, and if they are combined with schemes to match up people travelling to and from the same areas. No-one wants to drive to work with a garlic eater, a chatterbox, a bear with a sore head, or a sexual harasser, however fast the journey and however green the principle.