Development of Left-Turn Lane Warrants for Unsignalized Intersections (2013) / Chapter Skim
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5 CHAPTER 2 LITERATURE REVIEW -- INSTALLATION GUIDELINES A review of the literature was performed using many sources including research reports, state and federal design manuals, and handbooks. Although many procedures are currently in use by various organizations to determine the need for left-turn lanes, several are either very similar or identical.
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6 his work on a queuing model in which arrival and service rates are assumed to follow negative exponential distributions. He states that the probability of a through vehicle arriving behind a stopped, left-turning vehicle should not exceed 0.02 for 40 mph, 0.015 for 50 mph, and 0.01 for 60 mph.
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7 Table 2.
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8 Source: Neuman, T., Intersection Channelization Design Guide, NCHRP Report 279. Copyright, National Academy of Sciences, Washington, D.C., 1985.
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9 • When room for separate left-turn lanes is not available, traffic control alternatives should be investigated. Such alternatives to left-turn lane implementation include split phasing at signalized intersections (i.e., operating each approach individually)
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10 NCHRP Report 457 In 2001, Bonneson and Fontaine (12) in NCHRP Report 457 discussed the determination of when to consider a left-turn lane.
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11 Table 3. Fitzpatrick and Wolff (13)
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12 Table 4. Van Schalkwyk and Stover (14)
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14 Table 5. Modur et al.
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15 acceptance behavior. Ranade et al.
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16 Source: Kikuchi, S., and P Chakroborty, "Analysis of Left-Turn-Lane Warrants at Unsignalized T-Intersections on Two-Lane Roadways," in Transportation Research Record 1327, Figure 7, p.
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17 Source: Ranade, S., A Sadek, and J
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18 Table 6. Summary of selected left-turn lane literature guidelines based on Harmelink procedure.
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19 Table 8. Summary of state methods.
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20 Based on Green Book The following nine state manuals either include the same table of criteria as the values included in the Green Book (5) for determining the need for a left-turn lane or reference the Green Book: • Alaska Highway Preconstruction Manual (20)
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21 Delaware's DelDOT Road Design Manual (21) states that for unsignalized intersections, left-turn lanes should be provided: • At all median openings on high-speed divided highways, • On approaches where sight distance is limited, • At non-stopping approaches of rural arterials and collectors, and • At other approaches where required based on capacity and operational analysis.
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22 For example, the Connecticut manual (29) states: In general, exclusive left-turn lanes should be provided for at-grade intersections as follows: 1.
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23 Table 9. Colorado Access Code (38)
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24 General Guidance General guidance is provided in publications from: • Florida Driveway Information Guide (42) , • Louisiana's Roadway Design Procedures and Details (43)
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25 the applicant may be required to construct a Right Hand Passing Lane if they meet the criteria in Table [11] Condition 2.
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26 • Table 15 for rural multilane highways. Table 12.
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27 Table 13. New Mexico (46)
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28 Table 14. New Mexico (46)
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29 The Iowa Design Manual material is shown in Table 16. Note the left-turning volume criteria are for a deceleration lane rather than the left-turn bay.
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30 Table 17. South Dakota (50)
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31 Table 18. South Dakota (50)
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32 Table 19. Minnesota (48)
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33 • Warrant 8: Corridor Crash Experience -- on highway corridors that demonstrate a history of similar crash types suitable to correction by providing corridor-wide consistency in turn-lane use. • Warrant 9: Vehicular Volume Warrant -- at high-volume driveways (> 100 trips per day)
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34 Financial Consideration The Minnesota design manual also uses the term "economically feasible," which is a concept not discussed in most manuals. The Georgia manual mentions costs in association with left-turn lanes.
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35 Table 23. Summary of state design practice in providing right-turn lanes on rural highways (10)
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36 Where: V = total approach volume (veh) ; tc = time required to avoid possible rear-end crash (sec)
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37 Potts et al.
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38 for a site with a peak-hour through volume of 2200 veh/hr and a peak-hour right-turn volume of 220 veh/hr. The service life of the right-turn lane was assumed to be 20 years.
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39 Table 26. Potts et al.
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40 Table 27. Potts et al.
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41 Table 29. Potts et al.
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42 Table 31. Accident cost and severity distributions (58)
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