Some sort of advantage
For passengers, bus priority measures such as bus-only lanes are a godsend, making it much easier for bus companies to provide quick and reliable journeys. It makes sense that bus passengers should enjoy some sort of advantage over motorists, wrote Gavin Booth, director of Bus Users Scotland.
[Getting rid of bus lanes isn’t the answer to traffic congestion, Citymetric, January 28, 2015]
But not everybody agrees. Liverpool City Council recently abandoned all but four of its 26 bus lanes; and other UK cities are reported to be considering following Liverpool’s lead. In Belfast, ex-mayors have queued up to show support for a change in the system after reports of traffic bottlenecks and bus lanes lying empty.
Yet removing bus lanes entirely could be a recipe for disaster. “Freeing” important corridors for all traffic will only entice more cars into already congested town and city centres, which will adversely affect the environment and character of these places. A modern double-deck bus offers more than 70 seats, in a vehicle with a footprint little larger than three or four cars – cars that, at peak times, often only have a single occupant. It makes sense that the bus passengers should enjoy some sort of advantage.
Does it make sense? In a first-world metropolis with limited road space and sharply peaked travel flows, a certain amount of traffic congestion is virtually inevitable. Mr Booth has made the common errors of comparing full-occupancy buses against ‘single occupancy’ cars, and assuming that the relevant footprint is the roadspace occupied by (i.e. beneath) each vehicle.
For cars and buses, the relevant metrics are the actual (observed) occupancies, and the total roadspace attributable to each traveller. The average occupancy of a bus in Britain is 9 passengers. In many cases, the per capita roadspace used by bus-lane travellers is far higher than that of car users in other lanes. In Birmingham, the former Tyburn Road bus lane was a good example of the problem. It increased both aggregate journey times and automotive pollution.
The same considerations also apply to rail systems, such as the HS2 scheme. Although a full length HS2 train could carry 1,100 people in its 400-metre length, its per-capita dynamic land occupation would be ~120 square metres, so not much different to motorists on a highway.