Vehicle and driver standards are set at national, regional and global level.
Road vehicle standards are set chiefly to ensure that vehicles meet acceptable safety and environmental standards. There is ongoing pressure to ensure that newer vehicles meet improved safety and environmental standards.
In recent years there has been a wider recognition of the need to think of safety not only in terms of the passengers within the vehicle, but also about the impact that a vehicle can have on another road user. There has also been increased interest in thinking about the "whole-life" environmental impact of vehicles - thinking about their manufacture as well as their fuel efficiency, type and emissions. For many countries there are particular issues in relation to the older car market - as older vehicles are cheaper to buy but do not comply with current environmental and safety standards. Within the European Union targets have been set for the proportion of end-of-life vehicles that must be recycled.
Given the global nature of the road vehicle market, standard setting cannot be done in isolation, and the United Nations Economic Commission for Europe (UNECE) chairs a World Forum For The Harmonization Of Vehicle Regulations to achieve better international co-ordination. In addition to vehicle type approval, which sets the minimum standards that a vehicle must meet if it is to be sold within a country, additional testing is sometimes undertaken to measure the relative performance of different vehicles in terms of safety, environmental emissions etc. The European New Car Assessment Programme (EuroNCAP) provides motoring consumers with a realistic and independent assessment of the safety performance of some of the most popular cars sold in Europe on its searchable website. Each individual vehicle also needs to registered and insured before it can be used on the road.
Driver standards apply to both private drivers and commercial operators. Distinctions are made between the requirements for different types of vehicle - normally lower requirements are set for scooters or other low-powered vehicles than for cars, and more extensive requirements for HGVs and public service vehicles. Normally these requirements are met by undertaking a practical and a theoretical test within the home country. The driver licence is usually then held by the owner for life - though age or ill-health restrictions may apply. In some countries it is possible to obtain an International Driver's Licence which enables the user to drive in other countries. In most countries drivers also require individual insurance.
There are several road-specific restrictions which are normally set - particularly speed and weight restrictions. Speed limits are set based on many factors, such as road features, crash records, legal statutes, administrative judgment, engineering judgment and political decisions. Two common measures for setting speed limits are the design speed of the road and the 85th percentile of travel speeds (this latter is common in the USA). Increasingly greater sensitivity is applied to urban areas, particularly those with a high proportion of vulnerable road users. For example, residential areas often have very low speed limits, and there has been a recent trend towards the creation of "home zones" which are designed with pedestrians, children and other vulnerable road users in mind.
Weight restrictions are particularly important for road maintenance because deterioration is primarily due to accumulated damage from vehicles. According to a series of experiments carried out in the late 1950s, called the AASHO Road Test, it was empirically determined that the effective damage done to the road is roughly proportional to the 4th power of axle weight (that is, a 20% increase in axle load produces more than double the damage to the road). In most pavement design methodologies trucks are considered to be the sole cause of pavement deterioration. This means that setting appropriate limits weight restrictions, particularly for goods vehicles, is a crucial element of effective road maintenance and management.
Enforcement of driver and vehicle licensing requirements can be undertaken by the police and/or by specific licensing or enforcement organisations. Traffic offence enforcement again can be the responsibility of national or specific traffic police. Compliance and enforcement are major issues - they can be expensive to enforce and can create opportunities for corruption or bribery of officials. Particularly in large developing countries, enforcing speed and weight restrictions can be very difficult to achieve, with consequential adverse impacts on the cost of road maintenance and on road safety.