To remedy the empirical pitfalls of current chinese specifications and MUTCD 2009 guidelines in determining the placement distance of freeway exit advance guide signs,the driving maneuver of exiting traffic is analyze...To remedy the empirical pitfalls of current chinese specifications and MUTCD 2009 guidelines in determining the placement distance of freeway exit advance guide signs,the driving maneuver of exiting traffic is analyzed and the factors influencing placement distance are explored.Variables including the number of lanes,lane width,lane-changing time,driver＇s visual characteristics,sign installation methods and operating speeds on both freeway mainlines and exit ramps are found significant in explaining exit safety.Three different installation methods,namely ground installation,overhead installation and median installation,are introduced and their applicable conditions are given.Models,with the same structure among the three installation methods,are developed to compute the placement distance under different roadway geometric and traffic conditions.Taking overhead installation as an example,simulation results in TSIS-CORSIM show that the proposed distance reduces the number of lane changes in the area from the ramp nose to 500 m upstream by 58.93% compared with current Chinese specifications and 27.35% compared with MUTCD 2009 guidelines.Thus,the distances recommended in this paper have a better safety performance.展开更多
The influence of Tibetan characters on the visual recognition effects of Tibetan-Chinese bilingual guide signs based on drivers visual characteristics was studied.Four versions of Tibetan-Chinese bilingual guide signs...The influence of Tibetan characters on the visual recognition effects of Tibetan-Chinese bilingual guide signs based on drivers visual characteristics was studied.Four versions of Tibetan-Chinese bilingual guide signs with different heights and aspect ratios of Tibetan characters were designed,and corresponding road simulation models were established.10 Tibetan drivers and 10 Han drivers were selected to conduct driving simulation experiments using a driving simulator and eye tracker.The resultant data of the participant s pupil diameter and the visual recognition duration obtained from the eye tracker system were analyzed by analysis of variance.Combining results from the statistical analysis of driving simulator data and the questionnaire results on the visual recognition experience,it can be concluded that for Tibetan drivers,when the height of Tibetan characters was 2/3 of the height of Chinese characters,the visual recognition effect of the signs was better than that of 1/3 and 1/2 of the height of Chinese characters,indicating that increasing the height of Tibetan characters was conducive to improving the visual recognition effect of guide signs.The aspect ratio form of Tibetan had no significant effect on the level of difficulty encountered in drivers visual recognition,but it would affect the aesthetics of the bilingual guide signs.The recommended character height in Tibetan should be increased to improve the visual recognition process for Tibetan drivers.展开更多
基金Project of Florida Department of Transportation(No.BD54438)the National Key Technology R&D Program of China during the 11th Five-Year Plan Period(No.2006BAJ18B03)
文摘To remedy the empirical pitfalls of current chinese specifications and MUTCD 2009 guidelines in determining the placement distance of freeway exit advance guide signs,the driving maneuver of exiting traffic is analyzed and the factors influencing placement distance are explored.Variables including the number of lanes,lane width,lane-changing time,driver＇s visual characteristics,sign installation methods and operating speeds on both freeway mainlines and exit ramps are found significant in explaining exit safety.Three different installation methods,namely ground installation,overhead installation and median installation,are introduced and their applicable conditions are given.Models,with the same structure among the three installation methods,are developed to compute the placement distance under different roadway geometric and traffic conditions.Taking overhead installation as an example,simulation results in TSIS-CORSIM show that the proposed distance reduces the number of lane changes in the area from the ramp nose to 500 m upstream by 58.93% compared with current Chinese specifications and 27.35% compared with MUTCD 2009 guidelines.Thus,the distances recommended in this paper have a better safety performance.
基金The National Natural Science Foundation of China(No.51768063,51868068)Shanxi Provincial Innovation Center Project for Digital Road Design Technology(No.202104010911019)。
文摘The influence of Tibetan characters on the visual recognition effects of Tibetan-Chinese bilingual guide signs based on drivers visual characteristics was studied.Four versions of Tibetan-Chinese bilingual guide signs with different heights and aspect ratios of Tibetan characters were designed,and corresponding road simulation models were established.10 Tibetan drivers and 10 Han drivers were selected to conduct driving simulation experiments using a driving simulator and eye tracker.The resultant data of the participant s pupil diameter and the visual recognition duration obtained from the eye tracker system were analyzed by analysis of variance.Combining results from the statistical analysis of driving simulator data and the questionnaire results on the visual recognition experience,it can be concluded that for Tibetan drivers,when the height of Tibetan characters was 2/3 of the height of Chinese characters,the visual recognition effect of the signs was better than that of 1/3 and 1/2 of the height of Chinese characters,indicating that increasing the height of Tibetan characters was conducive to improving the visual recognition effect of guide signs.The aspect ratio form of Tibetan had no significant effect on the level of difficulty encountered in drivers visual recognition,but it would affect the aesthetics of the bilingual guide signs.The recommended character height in Tibetan should be increased to improve the visual recognition process for Tibetan drivers.
