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| Many crashes occurred around freeway exit ramp areas due to speeding and speed variance,. 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 AESL/ without AESL) were investigated to quantify the effectiveness. Based on the recommended values of AESL,an experiment application of AESL was conducted and 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. 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 |
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| Keywords:Freeway;Recommended Values;Advisory Exit Speed Limit ;Exit Ramp |
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