1. CE 578 Highway Traffic Operations Passing Lanes and Climbing Lanes HCM 2000

2. Objectives Concept of passing lane analysis Comparison of passing and climbing lanes analysis Understand application

3. PTSF Trends with and without a Passing Lane

4. HCM 2000 Concept of Auxiliary Lane Effects on PTSF PTSF d Directional PTSF estimate without the auxiliary lane LuLu Length of highway upstream of auxiliary lane (miles) L pl Length of passing lane (miles) L de Downstream length of highway with PTSF affected by auxiliary lane LdLd Length of highway downstream of auxiliary lane beyond the effect of the auxiliary lane

5. HCM 2000 Concept of Auxiliary Lane Effects on ATS ATS d Directional ATS estimate without the auxiliary lane LuLu Length of highway upstream of auxiliary lane (miles) L pl Length of passing lane (miles) L de Downstream length of highway with ATS affected by auxiliary lane LdLd Length of highway downstream of auxiliary lane beyond the effect of the auxiliary lane

6. Equation for PTSF d Adjustment

7. Equation for ATS d Adjustment

8. Method of Adjustment PTSFpl=A2/LT A2 = PTSFd * Lt – A1 A1 = (PTSFd – PTSF * fpl) * (Lpl) + (PTSFd – PTSF * fpl)*(Lde) * ½

9. 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

10. 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

11. Tables for L de and f pl : Passing and Climbing Lane

13. 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

14. Application to Passing Lanes Given: PTSF d = 80ATS d = 45 mph L t = 10 milesL u = 2 milesL pl = 1 mile v p_PTSF = v p_ATS = 700 pc/hr use Equations 20-20 and 20-22 for situations where L t < L u + L pl + L de