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原文传递 Methodology to Identify the Recommended Values of Advisory Exit Speed Limit on Freeway Exit Ramp in China

题名：	Methodology to Identify the Recommended Values of Advisory Exit Speed Limit on Freeway Exit Ramp in China
正文语种：	中文
作者：	Hu Sitao Xiang Qiaojun Yang Weiwei
作者单位：	School of Transportation,Southeast University Si Pai Lou ＃2,Nanjing, hina,210096 epartment of electrical and Mechanical Engineering,Jiangsu Food &Pharmaceutical Science ollege,Meicheng Rd #4,Huai'an, hina,223003
关键词：	Freeway Recommended Values Advisory Exit Speed Limit Exit Ramp
摘要：	Many crashes occurred around freeway exit ramp areas due to speeding and speed variance,especially in China.Traditionally, a posted ramp speed limit will be installed around physical gore area to manage speed around the area.Unfortunately, the field study showed that speeding and speed variance haven't been improved too much after introduction of posted ramp speed limit.An additional speed limit on deceleration lane may be needed to accommodate the speed changes ahead of physical gore, which could be functioned by Advisory Exit Speed Limit (AESL).However, no systematic research on the application of AESL has been reported yet.Thus, the primary objective of the paper is to develop a general methodology to identify and to validate the recommended values of AESL To achieve this goal, seven Sites with same exit ramp configuration in China were selected and two Scenarios (with AESI/ without AESL) were investigated to quantify the effectiveness.Two hours field data were collected for six Sites without AESL and the other one Site wtth/without AESL,the speed and deceleration rate of approximately 808 vehicles were obtained.The 85th percentile speed of 6 Sections at six Sites (Site 1 to Site 6) without AESL were used to identify the recommended values of AESL while the other one Site (Site 7) with two Scenarios was used for validation.The 85th percentile speeds of Section 6 (the physical gore) at three Sites exceed the posted ramp speed limit (40 km/h) more than 40% while those of other Sites exceed the posted ramp speed limit (60 km/h) only about 10%.So AESL is very necessary for the exit ramps which the posted ramp speed limit is 40 km/h.Based on the recommended values of AESL, an experiment application of AESL was conducted at Site 7.t-test was introduced to verify the differences in speed before and after experimental application of AESL.Results showed that with AESL, the mean speed and the 85th percentile speed reduced significantly at Site 7, but no obvious improvement on speed variance achieved even there were some tendencies on speed decrease on deceleration lane.The paper can provide researchers, managers and engineers with reasonable foundations, when determining the recommended values of AESL The proposed methodology will be especially helpful in China and other developing countries for similar exit ramps.
会议日期：	20131019
会议举办地点：	成都
会议名称：	2013年全国博士生学术论坛——交通运输工程领域拔尖创新人才博士生学术论坛
出版日期：	2013-10-19
母体文献：	2013年全国博士生学术论坛——交通运输工程领域拔尖创新人才博士生学术论坛论文集