Congestion charge zones are areas of a city which require drivers to pay a congestion charge if they wish to enter or pass through the zone. The amount of the charge varies, as does the way in which it is assessed. In a typical example, drivers pay a flat fee to enter the area during certain hours of the day. The City of London has a particularly famous congestion charge zone which was created in 2003, but numerous other cities have similar programs. The goal of such zones is to address some of the problems caused by traffic congestion.
When congestion charge zones are created, cities are usually hoping that the fee will deter some drivers, reducing the amount of traffic and thereby cutting down on congestion. In addition to facilitating the free flow of traffic, the reduction of traffic will also be beneficial for the environment, by reducing emissions associated with traffic congestion. The funds collected may be dedicated to maintenance of the roads, or used in government environmental programs.
Typically, within congestion charge zones, there are some important exemptions. Buses and alternative fuel vehicles are usually exempt, along with emergency services vehicles and human-powered vehicles like bicycles. Residents are also exempt from paying the charge, or they may qualify for a substantial discount. Some congestion charge zones also allow people to make bulk payments and qualify for a discount; for example, if one pays for a month at a time, the fees for individual days may be reduced.
A congestion charge zone may also have free throughways, depending on how it is laid out. In this case, as long as people stay on the section designated as free, they can drive through a congestion charge zone without paying. This allows people to cut across the zone, rather than driving around it, when they need to travel from outside the zone to another area outside the zone.
Reinforcement in congestion charge zones is often done with the use of remote monitoring such as CCTV systems which capture plates and send bills to the registered owners of the vehicles. This can be problematic, as in some regions, cases of people driving with false plates are becoming a problem. These individuals evade the charges with false or stolen plates which are registered to someone else. When this person receives the bill, the burden of proof is on this person to demonstrate that she or he was not driving in the zone on the day in question. The use of false plates also creates other legal problems which make it a very serious issue.