Research And Analysis On The Applicability Of Deceleration Facilities On Rural Highways

With the increasing number of rural road traffic accidents in China,various traffic calming measures,such as speed humps and speed bumps,have been widely used.on The rural highway facilities are also more common in Shanghai and other large cities.Because of their small road width,low speed limits and variety of vehicle types,.rural roads need special consideration when setting these reduction facilities.However,as to date,seldom systematic tests for the effectiveness of traffic calming on rural roads have been conducted.The purpose of this paper is to study applicability of deceleration facilities in rural highway from three angles: deceleration effect of four kinds of reduction facilities,the type of deceleration signs,the location of the signs.First,The paper analyzes the current situation of the rural highway and deceleration facilities and presents the experimental design of the research and the comparison of 85 th percentile speed reduction of 4 typical kinds of speed reduction measures for rural roads in China.The speed data measurement is performed on the spot with speed data at specified points and locations using Laser Gun from 90 m before to 30 m after deceleration facilities along the direction of the vehicle.After conducting several analyses,we prove wider speed humps lead to better speed reduction.In the meanwhile,according to statistical data,the optimization geometric design is conducted to make deceleration facilities more suitable to rural highways.When the speed was collected,we found that drivers ignored the previous deceleration sign.Under this circumstances,this article evaluated effectiveness of various types of speed hump signs,based on our large number of questionnaires.Statistics indicate that 73% of drivers prefer the sign indicating a speed hump combining graphics and text,rather than a graphical sign or the sign only containing text.In addition,we set the graphical sign and the sign combining graphics and text at Xiaodang Center Road in Shanghai Fengxian District and got speed values.By comparing 85 th percentile speed reduction between the graphical sign and the sign combining graphics and text,we validate the sign combining graphics and text as promoting more effective deceleration.In the end,the setting position of the sign board is optimized through the driving simulator experiment with Xiaodang Road as a case.Eight experimental scenarios: pre position 25 m,30m,35 m,40m,45 m,,50 m,55m,60 m,are set up and the vehicle speed values are obtained.The results of the experiment prove that signs are the best in position that 50 meters before the speed hump of the rural road with 40km/h limited speed,3.5m lane width and free traffic flow,for the most stable speed deceleration and the largest rate of decline.