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CE 578 Highway Traffic Operations

CE 578 Highway Traffic Operations. Crawl Regions and Specific Grades HCM 2000. Objectives. Model vehicle operations on grades using the HCM 2000 two-lane highway directional analysis procedure Evaluate need for climbing lanes. When to Use HCM 2000 Specific Grades Procedure: Upgrades. NO

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CE 578 Highway Traffic Operations

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  1. CE 578 Highway Traffic Operations Crawl Regions and Specific Grades HCM 2000 Michael Dixon

  2. Objectives • Model vehicle operations on grades using the HCM 2000 two-lane highway directional analysis procedure • Evaluate need for climbing lanes Michael Dixon

  3. When to Use HCM 2000 Specific Grades Procedure: Upgrades • NO • Level Terrain: • Rolling Terrain: • MAYBE • MUST Michael Dixon

  4. % Grade • Upgrade same as downgrade • Composite grade  Total elevation change / length Michael Dixon

  5. Length Michael Dixon

  6. Length (composite grade) Michael Dixon

  7. How to Use the HCM 2000 Specific Grades Procedure: Upgrades • Use the modified directional analysis procedure making the following replacements • Average Travel Speeds • fG: • ET and ER: • PTSF • fG: • ET and ER: • Everything else is the same Michael Dixon

  8. Criteria for Evaluating the Need for Climbing Lanes (AASHTO) • Upgrade traffic flow rate in excess of 200 vehicles per hour • Upgrade truck flow rate in excess of 20 vehicles per hour • One of the following conditions exists: • A 10 mph or greater reduction is expected for typical heavy truck • Level of service E or F exists on the grade • A reduction of two or more levels of service is experienced when moving from the approach segment to the grade Michael Dixon

  9. When to Use HCM 2000 Specific Grades Procedure: Downgrades • Opposing direction of any upgrade Michael Dixon

  10. How to Use the HCM 2000 Specific Grades Procedure: Downgrades • Use the modified directional analysis procedure making the following replacements • Average Travel Speeds (no trucks at crawl speeds) • fG: • ET and ER: Michael Dixon

  11. How to Use the HCM 2000 Specific Grades Procedure: Downgrades (cont.) • Average Travel Speeds (trucks at crawl speeds) • fHV: • fG: • ET and ER: • ETC: • Extra data: percentage of trucks operating at crawl speeds Michael Dixon

  12. How to Use the HCM 2000 Specific Grades Procedure: Downgrades (cont.) Michael Dixon

  13. How to Use the HCM 2000 Specific Grades Procedure: Downgrades (cont.) • PTSF • fG: • ET and ER: • Everything else is the same Michael Dixon

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