• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.12 no.2
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• pp.52-62
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• 2013

Design Hourly Factor(DHF) is defined as the ratio of design hourly volume(DHV) to Average Annual Daily Traffic(AADT). Generally DHV used the 30th rank hourly volume. But this case DHV is affected by holiday volumes so the road is at risk for overdesigning. Computing K factor is available for counting 8,760 hour traffic volume, but it is impossible except permanent traffic counts. This study applied three method to make DHF, using 30th rank hourly volume to make DHF(method 1), using peak hour volume to make DHF(method 2). Another way to make DHF, rank hourly volumes ordered descending connect a curve smoothly to find the point which changes drastic(method 3). That point is design hour, thus design hourly factor is able to be computed. In addition road classified 3 type for national highway using factor analysis and cluster analysis, so we can analyze the characteristic of DHF by road type. DHF which was used method 1 is the largest at any other method. There is no difference in DHF by road type at method 2. This result shows for this reason because peak hour is hard to describe the characteristic of hourly volume change. DHF which was used method 3 is similar to HCM except recreation road but 118th rank hourly volume is appropriate.

• Journal of Korean Society of Transportation
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• v.22 no.2 s.73
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• pp.55-63
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• 2004

기존의 설계시간순위 결정은 "순위곡선의 기울기가 완만해지는 지점"이라는 정성적인 기준을 사용하였다. 따라서, 분석자마다 서로 다른 결과를 도출하고 도로 설계시 고려해야하는 두요소(교통혼잡, 경제성)를 전혀 고려하지 못하는 문제점이 있다. 또한 현재의 도로 설계시 대상으로 삼는 시간교통량은 국내 도로의 교통특성이 설, 추석 등의 연휴에 집중적으로 몰리는 등 외국과 그 특성이 상이함에도 불구하고 미국과 동일한 상위 30순위 교통량을 사용한다. 상위 30순위 교통량을 설계시간순위로 하는 경우, 상위 30순위교통량 중 휴일교통량의 비율이 74.1%(설, 추석 연휴 39.7%)로 휴일 집중 교통량의 영향을 크게 받으며, 연중 최대교통량이 용량의 85.2% 에 불과해 도로가 과다 설계된다. 본 연구에서는 목표년도의 연중 최대시간교통량이 용량에 도달하는 순위를 설계시간순위로 하였으며, 분석결과 상위 150순위가 교통혼잡과 도로의 경제성을 모두 고려할 수 있는 설계시간순위로 산정되었다. 설계시간순위를 150순위로 할 경우 현행 설계순위인 30순위에 비해 휴일비율 13.8% 감소, 최대시간교통량의 용량비율($V_1/C_a$) 16.0% 증가의 효과가 있을 것으로 분석되었다. - 현행 설계시간순위(30순위) : 휴일비율 74.1%(설, 추석 비율 39.7%), $V_1/C_a$ 85.2% - 제안 설계시간순위(150순위) : 휴일비율 60.3%(설, 추석비율 23.0%), $V_1/C_a$ 101.2%

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.6
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• pp.2427-2435
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• 2013

Design hourly volume and the K-factor, first proposed by FHWA in the 1950s, is based on the 30th hourly traffic volume during a year (out of 8,760 hours). It was used when surveying the traffic volume was laborious in the past and is still being used now although it leaves some to be desired for practical applications. More reasonable K-factor for better design, based on theoretical evidence, is needed. This paper proposes the knee searching method based on simple linear regression to find out the inflection point of the volume ranking curve that describe the annual 8,760 hourly traffic volumes. The method was applied to the Chungcheong province's national highway, and the results were compared to the existing guidelines' values of K-factors. Identified design hourly traffic volumes ranked between 43rd to 694th, which is much lower than the 30th volume, meaning that some overdesign examples are inevitable if the conventional $30^{th}$ volume is used.