This paper describes a general 30 km/h speed limit introduction project in the Austrian city of Graz on 1 September 1992, except for priority roads. The regulation is seen as a two-year trial. The priority roads have a 50 km/h limit in general. The Graz 30 km/h speed limit model consisted of: (1) traffic regulation; (2) public relations and the public awareness formation; and (3) police supervision. The general 30 km/h speed limit introduction is a part of an integrated transport plan. Important results of the before and after study into the 30 km/h speed limit introduction effects are: (a) The acceptance of the measure by all road users has risen greatly after the introduction; (b) There has been a significant reduction in the number of both accidents (12%) and of seriously injured persons (about 20%) referring to the whole road network; (c) The maximum speeds have gone down greatly on both the 30 km/h speed limit roads and on the priority roads; (d) Road users show more consideration to one another on 30 km/h speed limit roads; (e) A reduction of the noise level up to 2.5 dB on 30 km/h speed limit roads was shown in the after study; and (f) the nitrogen oxide (NOx) emissions on the 30 km/h speed limit road network reduced by a quarter.
Samenvatting