volumes and speeds To reduce road crash rates, injuries and fatalities to all road users Reduce greenhouse gas emissions, air pollution and noise pollution Foment an area where pedestrians, cyclists and motorists coexist safely and comfortably Develop public space that is open and safe for everyone, including people with disabilities Increase the space available for walking, biking, and people on the street to eat, play and enjoy life Provide a safe area for children in school zones Increase real estate values of local homes and businesses Increase the economic vitality of the area Strengthen the sense of community Benefits Compared to normal signed but unenforced speed limits, these type of speed zone generally deliver the required traffic speeds because of their traffic calming aspects. A 2015 review of various studies found that 20 mph zones and limits are effective in reducing accidents and injuries, traffic speed and volume. Death is much less likely if a pedestrian is hit by a car travelling at 20 mph than at 30 mph or more. The limited evidence from existing 20 mph schemes shows marked reductions in deaths and casualties. Lower traffic speeds contributes towards less congestions, less air pollution, lower emissions, stronger communities and reduced obesity. Prevalence Europe In European countries 30 km/h zones have been used widely. On September 1, 1992, the city of Graz, Austria, became the first European city to implement a citywide 30 km/h limit on all roads except its largest. Significant 30 km/h zones are ubiquitous across the Netherlands. In Switzerland 30 km/h zones have been allowed by law since 1989 and they were first established in Zürich in 1991. In 2017, most of all IRTAD countries have a default speed limit in urban areas of 50 km/h, with various lower speeds, for instance, in the Netherlands, 70% of the urban roads are limited to 30 km/h. A network of 67 European NGOs organised a European Citizens' Initiative (ECI) "30kmh - making streets liveable" collected signatures of support for a 30 km/h speed limit as the normal limit for the European Union. 50 km/h speed limits would then become exceptions. Local authorities would be able to decide on these exceptions and set other speed limits on their street network. In Munich 80% of the 2,300 kilometers of urban road network have a speed limit of 30 km/h or less, remaining roads are limited at 50 km/h. 85% of