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Bus• lanes a threat to traffic flow?

18th June 1971, Page 51
18th June 1971
Page 51
Page 51, 18th June 1971 — Bus• lanes a threat to traffic flow?
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Which of the following most accurately describes the problem?

by VV. S. Clarke, traffic officer, Freight Transport Association

The GLC's recent announcement that taxis and coaches are to be allowed to use bus lanes has focused attention on these reserved road sections. This article confirms that bus lanes are not universally regarded as a good thing.

BUS OPERATORS today form one of the most vocal groups in the field of traffic management. Their call is for everincreasing special facilities for public service vehicles. The favourite animal is the bus lane.

Understandably, their main enemy is the private car and particularly the commuter car. Such cars, it is argued, are a prime cause of congestion, which in turn leads to poor bus services and irregular running, and carry on average one and a half people compared with the 60 to 70 plus of the modern bus.

Seldom if ever do the bus operators acknowledge that there are other forms of essential traffic in urban areas. Indeed, London Transport has on occasions called for bans on the flow of heavy commercial vehicles in London and even for bans on operators of tourist coaches.

Even the Department of the Environment's working group on bus demonstration projects emphasized the importance of the economic use of road space for carrying people without highlighting the equal importance of the movement and delivery /collection of goods.

Admittedly, the group's report accepted that bus priority schemes involved problems for other traffic and might give rise to accident risks. Surprisingly, there is apparently little accurate data on the results of most schemes now in operation other than operators' claims, made without good supporting evidence of advantages. Nevertheless, the working group report called for increased experiments and further pressure by bus interests for more bus priority projects.

Enthusiasm by local authorities and the police—who by and large have the greatest local traffic management expertise—for bus priority schemes appears to be remarkably small. Indeed, in the bus operators' views both these groups need education in this field. A danger of the pressure from bus interests is that local authorities may succumb to it to the extent of instituting schemes which to some extent will be against their better judgment.

Goods vehicle operators must not fall into the same trap of imagining that they have a divine right to road space. What is necessary, and this it is the ETA's basic policy to achieve, is a proper appreciation of the fact that the movement of people and the movement of goods and provision of services are complementary. The overall economic result is what matters.

The main justification for bus only, lanes in the same direction as the main traffic flow is that of giving the bus priority as it is the most economical passenger-carrying vehicle. This in itself can bring practical difficulties that must severely limit possible sites for this treatment. A bus lane might enable buses to bypass congestion at a particular point but often, as ETA observations have shown, congestion will be caused by inadequate traffic capacity of the road and this in turn makes the possibility of a bus lane impractical.

Although much of the other traffic may consist of private cars with few occupants, there will be a substantial proportion of commercial and other essential traffic including taxis. A bus-lane which speeds buses for, say, up to a quarter-mile but causes increased congestion overall, perhaps slowing down the half-mile before the bus-lane, is obviously self-defeating. Even where there is any saving in bus journey time it tends to be normal and quite out of proportion to the overall loss to other forms of traffic.

The centre of Vauxhall Bridge, London, provides a good example of a situation where there is now congestion in the main traffic lanes but with a large section of the road—the central bus lane—being underutilized. As a result, traffic can tail back and prevent buses from getting on to the bridge and the bus lane.

Another danger of bus lanes—typified by the original London Park Lane scheme— is that vehicles wishing to turn into side-turnings across the bus lane do so at considerable risk. The caution required can considerably cut traffic flow in the lane adjacent to the bus lane. Similar difficulties arise with vehicles having to join a busy road across a bus lane. An odd feature, incidentally, of the original Park Lane scheme, was that for much of its length it was taken up with bus stops. Buses were thus obstructing themselves and trying to enter or leave the lane half-way along its length. Unless buses are confined to the reserved lane they move in and out and cause congestion to other traffic.

Contra-flow systems are normally put into one-way streets. Unless the street is exceptionally wide the effect of the contra-flow lane will be to cut the traffic flow of the one-way system. The gain to the contra-flowing bus is therefore offset by a decrease in the number of vehicles, including buses, flowing in the main direction. If there are light-controlled junctions along the route an additional phase has to be introduced.

Each extra phase of course means longer red phases which in turn mean possible congestion and reduced traffic flow on routes leading to the junction. It is more than likely that the street concerned will be a main shopping street with the result that there will also be a complete denial of ready access to premises on the side of the street where the bus lane operates. This may well lead to delivery vehicles stopping either on the opposite side of the road, and their drivers carrying goods across to the shops, or stopping alongside the reserved bus lane. This in turi will lead to a further reduction in the main traffic flow.

Danger can also occur where passengers from cars are set down and picked up alongside the bus lane instead of against the kerb.

With same-direction lanes the problem is not so serious as these normally operate only at peak hours. A contra-flow lane must for safety reasons be divided physically from the rest of the road and as such is permanent.

Those schemes which allow a bus to take a short cut over a limited section of street—perhaps to cut off the corner of a one-way system or which permit buses to take right or left turns banned to other traffic—are, in general, measures which do not overly upset the general traffic pattern. Even so, tail back from the bus waiting to take a "banned" right turn can build up and negate the overall advantage of the ban.

Bus-priority schemes obviously have a role to play in attracting back lost passengers. They must not be judged, however, solely on their effect on individual groups of buses. Without careful examination, what appears to be a localized gain could turn out to be a loss to the community at large.


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