Objective	Singapore Area Licensing (paper-based system)	Singapore Electronic Road Pricing (change from paper-based system)	Norwegian Toll Rings	Value Pricing in San Diego	London Congestion Charging Implementation	London Congestion Charging Western Extension Study
				?
	?	?

	= Weakest possible positive contribution,		= strongest possible positive contribution
	= Weakest possible negative contribution		= strongest possible negative contribution

= No contribution

Summary of each case study's contribution to alleviation of key problems

Objective	Singapore Area Licensing (paper-based system)	Singapore Electronic Road Pricing (change from paper-based system)	Norwegian Toll Rings	Value Pricing in San Diego	London Congestion Charging Implementation	London Congestion Charging Western Extension Study
Congestion-related delay
Congestion-related unreliability
Community severance
Visual intrusion
Lack of amenity
Global warming
Local air pollution
Noise
Reduction of green space
Damage to environmentally sensitive sites
Poor accessibility for those without a car and those with mobility impairments
Disproportionate disadvantaging of particular social or geographic groups
Number, severity and risk of accidents
Suppression of the potential for economic activity in the area	?	?

	= Weakest possible positive contribution,		= strongest possible positive contribution
	= Weakest possible negative contribution		= strongest possible negative contribution

= No contribution

Appropriate contexts

Urban road charging is applicable to any city. However given that there are costs associated with its implementation, it is recommended that cities considering the introduction of urban road charging should carry out a cost-benefit analysis of doing so.

Based on our above assessments, urban road charging will be particularly applicable in cities where:

• there is an identifiable problem of traffic congestion; or
  
• there has been a decision not to increase the capacity of the road network which may, without efforts to manage demand, lead to problems of traffic congestion;
  
• there is (or there is scope for) a good public transport network;
  
• there is a degree of economic autonomy in relation to neighbouring cities;
  
• there is an identified need to raise revenue for particular projects.

Even within a city or town there will be contexts where urban road charging will be more or less appropriate. Appropriate area-types indicates which area-types are likely to be most and least appropriate.

Area type	Suitability
City centre
Dense inner suburb
Medium density outer suburb
Less dense outer suburb
District centre
Corridor
Small town
Tourist town

= Least suitable area type

= Most suitable area type

Planners are often concerned at the potentially adverse impact on the economy of the charged area if charging encourages drivers to travel elsewhere, there is no empirical evidence however of this having happened in London or any of the other cities where congestion charging has been implemented. However, a number of desktop and attitudinal studies have concluded that there would be minor negative economic impacts, although these are very much dependent upon the characteristics of the urban centre (e.g. Flowerdew 1994, Richards et al, 1996, Still, 1996). Most studies have highlighted the need for complementary public transport improvements.

The second concern relates to the equity implications. Bus users, pedestrians and cyclists will benefit; rail users will be little affected except, perhaps, by increased patronage, although in the longer term increased patronage may encourage an improved service. If the scheme is a mileage-based system then users of commercial vehicles that drive many miles will be disadvantaged whilst commuters may be net beneficiaries with the reduced congestion more than compensating them. If on the other hand a set daily fee is paid for unlimited mileage then it is likely that commercial drivers will benefit relative to commuters.