A Study Of Speed Limit Signs For Qiandaohu Branch Of Hangzhou-Xin'anjiang-Jingdezhen Expressway

It is mandatory for expressways to limit speed,and this is currently a common practice throughout the world.The speed limit of expressway is established by road and transport administrations, as stipulated by law, in accordance with specific road and traffic conditions and released by traffic signs.This dissertation studies the speed limit of the qiandaohu branch of Hangzhou-Xin'anjiang- Jingdezhen expressway. The qiandaohu branch of Hangzhou-Xin'anjiang-Jingdezhen expressway is a two-way four-lanes trans-mountain expressway,with a designed speed is 80km/h.Now the speed limit is 70km / h in the tunuels and 80km/h elsewhere.However since its opening, the speed limit has been widely questioned as being too low;therefore, the traffic authorities have decided to scrutinize the indicated value of speed limit and form a scientific judgment.This research has been done on the basisof practical survey and theoretical analysis. By conducting practical survey, we have accessed to the actual situation of vehicles running in the expressway. By according to the model ,we can forecast speed under the different expressway conditions. These two areas can provide the supporting data and factual evidence for determining the values of the limit. By doing theoretical analysis, we have checked the technical standards and norms on the basic conditions of expressways such as the plane curve, superelevation, sight-distance, the width of road-base, slope, interchange and the tunnel.Then further combined the speed, the basic conditions of the expressway, service level ,tunnel and the traffic safety for comprehensive analysis of the feasibility of raising speed limit.Finally, and considered the costs of projects,a suggestion scheme for the signs values of the speed limit for Qiandaohu Branch of Hangzhou-Xin'anjiang-Jingdezhen Expressway is proposed: in the two-way traffic volume is less than 16,000 pcu / d circumstances, the speed limit of cars in two sections (k0+750~k5+600, k9+400~kl4+500,except in tunnels) increases to 100 km / h, the speed limit of large and medium-sized vehicles is 80km/h in whole sections. After the suggestion scheme, th speed-up sections is 8.865km (of the full-length with 44.2%). The running time of cars in the whole section is 13.7 minutes , shortened by about 1.9 minutes(of the whole time with 12.2 %).