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CE 578 Highway Traffic Operations. Passing Lanes and Climbing Lanes HCM 2000. Objectives. Concept of passing lane analysis Comparison of passing and climbing lanes analysis Understand application. PTSF Trends with and without a Passing Lane.
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CE 578 Highway Traffic Operations Passing Lanes and Climbing Lanes HCM 2000
Objectives • Concept of passing lane analysis • Comparison of passing and climbing lanes analysis • Understand application
Method of Adjustment • PTSFpl = A2/LT • A2 = PTSFd * Lt – A1 • A1 = (PTSFd – PTSF * fpl) * (Lpl) + (PTSFd – PTSF * fpl)*(Lde) * ½
Basic Assumptions • Directional PTSF and ATS are constant • No relation between passing lane length and downstream affected length • No affect of adjacent auxiliary lanes • Independent of passing location relative to grade
Overall HCM 2000 Process of Analyzing Auxiliary Lanes • An auxiliary lane is a second lane added for the benefit of traffic operations… • Perform directional analysis • Determine location and length of the auxiliary lane • Secure factors • Calculate adjustments • Adjust ATS and PTSF values
Basic Trends • As volume rises effectiveness of auxiliary lane ___________ • Effectiveness of a climbing lane is _____________than that of a passing lane • PTSF is _______sensitive to auxiliary lane effects
Application to Passing Lanes Given: PTSFd = 80 ATSd = 45 mph Lt = 10 miles Lu = 2 miles Lpl = 1 mile vp_PTSF = vp_ATS = 700 pc/hr use Equations 20-20 and 20-22 for situations where Lt < Lu + Lpl + Lde