Select Committee on Environment, Transport and Regional Affairs Appendices to the Minutes of Evidence

Annex 1


  Let current quantity of road traffic = 100. Reasonably free-flowing conditions are, in most provincial cities, achieved at present in school holiday periods when traffic may be reduced by, say, 10 per cent = 90. The White Paper on Integrated Transport says, if nothing is done, car traffic could increase by one third over the next 20 years = 133. But in order to keep urban roads reasonably free-flowing at peak times, traffic has to be no more than 90—which is a reduction of 10 per cent on current levels and a 32.3 per cent reduction in what the levels will otherwise reach in 20 years time.

  Professor David Begg, now Chairman of the Commission for Integrated Transport, said, earlier this year, that car trips account for 87 per cent of land passenger kilometres and if this was to be reduced by just 1 per cent by car users transferring to buses, bus passenger kilometres would have to increase by 17 per cent. So if car use in 20 years time has to reduce from 133 to 90 = 43 and each of those 43 points would require a 17 per cent increase in bus use, then it follows that bus use would have to increase by 731 per cent (unless people are to be prohibited or discouraged in some way from making those trips at all). 731 per cent can also be expressed as being an average of 36.6 per cent per annum over 20 years—36 times the actual increase in bus use achieved from 1997 to 1998, every year for the next 20 years.

  Depending on what you regard as the necessary reduction on present traffic levels to achieve a reasonable or even tolerable level of road traffic, so, of course, the percentage transfer changes. If, for instance you assume a 20 per cent reduction is needed then the figures change so that a 53 per cent transfer would be needed, which, using Professor Begg's conversion factor means a 901 per cent increase in bus use. If you think that a reduction of road traffic of only 5 per cent would do the trick, the figures become 38 per cent reduction need, so a 646 per cent increase in bus use is implied. Even if you are quite happy with current road traffic levels, and want to keep them the same, in 20 years they will probably have grown (according to DETR) by 33 per cent, so to get them back to present levels would require a 561 per cent increase in bus use (33 x 17 per cent)—an average of 28 per cent per annum over the 20 years. Even if traffic increases by only 10 per cent over the coming 20 years, and it is felt that present day traffic congestion levels are tolerable, on Professor Begg's figures, a 170 per cent increase in bus use is necessary to achieve a situation in which urban car traffic (and hence traffic congestion) does not increase.

  This calculation may seem to produce such grotesque results as to be unbelievable, but the question must be, is the calculation methodology wrong or are the "desired state" assumptions wrong or is Professor Begg wrong about the increase of bus use which would be required to reduce car traffic by 1 per cent?

  We submit that the methodology is sound (everything is calculated against the base year of 1999); Professor Begg is well informed, so the 1 per cent reduction in car use means 17 per cent increase in bus use is accurate; and that traffic levels in 20 years time cannot possibly be allowed to be 20 per cent (or even 10 per cent) up on now as, without massive road building, the resulting implications for grid-lock, pollution, health and the general sanity of the urban population are beyond contemplation. Most importantly, of course, it is inconceivable that buses alone could handle anything like the above levels of increase—but integrated networks of quality buses and light rail transit can do so—but only if they are actually built!

previous page contents next page

House of Commons home page Parliament home page House of Lords home page search page enquiries index

© Parliamentary copyright 2000
Prepared 8 June 2000