Sustainable design of rural roads with 2+1 road design: Levels of service and traffic flow performance

• Published in: KSCE journal of civil engineering Vol. 20; no. 3; pp. 1032 - 1039
• Main Authors: Choi, Jaisung, Kim, Youngrok, Bergh, Torsten, Kim, Sangyoup, Kim, Sungkyu
• Format: Journal Article
• Language: English
• Published: Seoul Korean Society of Civil Engineers 01.04.2016; Springer Nature B.V; 대한토목학회
• Subjects: Civil Engineering; Design; Design analysis; Detectors; Effectiveness; Engineering; Field study; Geotechnical Engineering & Applied Earth Sciences; Highways; Industrial Pollution Prevention; Manuals; Mobility; Road construction; Road design; Roads; Roads & highways; Rural roads; Sustainability; Sustainable design; Sustainable Urban Transportation System; Traffic flow; Vehicle safety; 토목공학; TWOPAS; traffic delay; levels of service; 2+1 roads; measures of effectiveness; percent time spent following
• ISSN: 1226-7988; 1976-3808
• DOI: 10.1007/s12205-016-1696-1

This paper provides research results of a study to assess the driver performance levels of a 2+1 road, a special type of road involving intermediate cross section that is applied where a four-lane roadway construction is unjustifiable and the use of a two-lane road design may not provide the desired level of mobility. Despite increased driver safety, the use of the 2+1 road involves a problem that the South Korean government cannot assess the mobility effects of 2+1 roads, because the current Korean Highway Capacity Manual lacks the level of service procedure for 2+1 roads. Hence, research is required to provide potential measures of effectiveness for describing traffic flows in 2+1 roads and establish a reliable level of service analysis procedure. To address this issue, we applied the following approach: (1) existing research concerning 2+1 road design and flow performance was reviewed; (2) a field study was conducted in 2+1 roads with video cameras and traffic detectors to investigate traffic flow conditions; (3) candidate measures of effectiveness for describing traffic flow in 2+1 roads were identified based on field study results as well as TWOPAS simulation efforts; and (4) an analysis procedure applicable to determine levels of traffic flow service for 2+1 roads was proposed. We also examined how our proposed procedure would perform based on a case study. It was found that the percent time spent following would represent the most appropriate measures of effectiveness and that realistic output may be produced with our proposed procedure.