In some developing-country megacities, there is currently a shortage of urban parking. In China, for example, there are few parking facilities available for private vehicles in most of the major cities. Given burgeoning demand for private cars, new auto owners are beginning to engage in searches for parking. The need for parking may will spark the redevelopment of urban parcels into parking structures as the prices bid for parking spaces rise. Redevelopment may, in turn, exacerbate traffic congestion in Chinese cities as it has in other motorizing countries. When this process begins, it is very important to charge users for the full costs of both parking and congestion. Despite the apparent benefit of providing parking, an ample supply of free off-street parking can hurt urban transport by promoting private vehicle travel. Studies show that parking policy in the United States, for example, where 75 percent of commuters park in free off-street parking provided by employers, strongly favors automobile use.

Another complement to or possible surrogate for congestion pricing is gasoline taxation, particularly if the funds are spent to finance transportation improvements. Taxing of fuel is relatively transparent to implement, administer, and enforce. Taxation at the pump generally induces all drivers to consume less fuel and to use their vehicles more prudently than they would otherwise. Although taxing of fuel is a very imperfect proxy for congestion pricing, in many cases it may be the only practical measure in terms of enforcement and collection, particularly in the context of developing countries. In addition, if the revenues are dedicated to transportation investment and improvements, taxpayers are generally willing to accept the extra cost.

In general, measures based on physical restraint of vehicle movement are more problematic and ambiguous in their outcome than the financial restraint measures discussed above. One of the most common physical restraint measures is heavy-vehicle restrictions, which attempt to minimize the congestion, noise and air pollution, and premature road deterioration these vehicles can cause. While such bans can be effective, they can also adversely affect urban business and commerce, and need to be coordinated with other shipping policies, such as limitations in delivery hours or transfers to more environmentally acceptable vehicles for local delivery.

Traffic flow has been reduced in some cities by dividing the central business district into cells. Cars can travel freely within one cell or zone, but must travel by an outer-ring road to enter the next zone. These zoning systems are designed to limit through-traffic on dense center city streets, increase city street safety, and reduce transport-related air and noise pollution in the center city. Public transport, pedestrian, and nonmotorized transport facilities can be developed to allow for travel between zones. The city of Gothenburg, Sweden, for example, developed such a cell system, which successfully decreased traffic accidents by 56 percent and lowered center city traffic volume by 45 percent between 1970 and 1982 (Organization for Economic Co-operation and Development, 1988). The completed