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This document explores the analysis of passing and climbing lanes in highway traffic operations as per HCM 2000 guidelines. It covers the objectives and concepts behind passing lane analysis, offers a comparison of passing and climbing lanes, and explains the impact of auxiliary lanes on PTSF (Passenger Car Time Service Flow) and ATS (Average Travel Speed). Emphasizing basic assumptions, it outlines a systematic approach for analyzing auxiliary lanes, including directional analysis and adjustments to PTSF and ATS values based on traffic volume.
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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