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Road Safety Audit Seminar Collision Modification Factors

Road Safety Audit Seminar Collision Modification Factors. 15 st May 2018. George Frisby. Road Safety Audit Seminar May 2018. Presentation Methodology. What is a CMF Where they are currently being used in Ireland Why they would be useful in the RSA process Examples CMF Sources

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Road Safety Audit Seminar Collision Modification Factors

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  1. Road Safety Audit Seminar Collision Modification Factors 15st May 2018 George Frisby

  2. Road Safety Audit Seminar May 2018 Presentation Methodology • What is a CMF • Where they are currently being used in Ireland • Why they would be useful in the RSA process • Examples • CMF Sources • Considerations in using CMF’s • Summary

  3. Road Safety Audit Seminar May 2018 What is a CMF CMF is the ratio of the expected collision frequency after a solution is implemented to the estimated collision frequency beforehand. i.e. CMF for replacing a crossroads with a roundabout is 0.62. This means that collisions are expected to reduce by 38% as a result of implementing the above solution. CFM’s have been determined from studies where collision frequencies beforehand were compared to collision frequencies after implementing a particular solution CMF’s are used to compute the expected reduction in collisions after implementing a given countermeasure at a specific site A CMF of 1 would mean that there is an anticipation of no changes in the collision frequency and a CMF of 0 would mean an anticipation that the collision would no longer occur after the solution is implemented; therefore the lower the CMF the more effective the solution.

  4. Where are CMF’s Being Used RSI Process HD15 Assessments 2012: TEN-T network inspected 2012: Non- TEN-T routes inspected* 2013: Non- TEN-T routes inspected* 2014: Non- TEN-T routes inspected* 2015: Non- TEN-T routes inspected* 2016/17: Review of all RSIs 2016/17: Implementation of RSI Recommendations *Inspection order based on GE-STY-01022 Network Safety Analysis Results

  5. Road Safety Audit Seminar May 2018 Why use CMF’s • CMF’s are a useful tool to compare alternatives solutions. • CMF’s can be used as a way to measure the effectiveness of a • solution. • It can help you determine if a particular solution will result in a • significant reduction in collisions • It will help you to choose the most suitable solution for a • particular issue.

  6. Road Safety Audit Seminar May 2018 Example Embankment side slope on outside of low radius bend (400m)

  7. Road Safety Audit Seminar May 2018 Possible Solutions • Increase curve radius • Flatten the side slopes • Provide a clear zone • Install chevrons • Erect Safety Barrier

  8. Road Safety Audit Seminar May 2018 Measure: Increase Curve Radius CMF of 0.77

  9. Road Safety Audit Seminar May 2018 Measure: Reduce Side Slope CMF of 0.85

  10. Road Safety Audit Seminar May 2018 Measure: Provide Clear Zone CMF of 0.49

  11. Road Safety Audit Seminar May 2018 Measure: Install Chevrons CMF of 0.78

  12. Road Safety Audit Seminar May 2018 Measure: Erect Safety Barrier CMF of 0.49

  13. Road Safety Audit Seminar May 2018 Summary A review of the CMF’s suggests to provide a clear zone or erect a safety barrier Multiple measures at the same location? Some research say multiply the CMF’s while other say use the lowest. Using the lowest may under estimate the benefit while multiplying may over estimate the benefits.

  14. Road Safety Audit Seminar May 2018 CMF Sources PRACT Repository(PredictingRoad ACcidents - a Transferable methodology across Europe CMF Clearing House Repository TII Road Safety Remedial Measures Programme Austroads PIARC Safety Cube Repository Highway Safety Manual

  15. Road Safety Audit Seminar May 2018 CMF Sources

  16. Road Safety Audit Seminar May 2018 CMF Sources

  17. Road Safety Audit Seminar May 2018 CMF Sources

  18. Road Safety Audit Seminar May 2018 CMF Sources

  19. Road Safety Audit Seminar May 2018 CMF Sources

  20. Road Safety Audit Seminar May 2018 CMF Sources

  21. Road Safety Audit Seminar May 2018 Considerations in using CMF’s • They are a starting point • Use with caution • Check collision type • Use CMF’s that are stated to be reasonably accurate • Target higher severity collisions

  22. Road Safety Audit Seminar May 2018 Summary • A CMF is a measure of the effectiveness of a particular solution • Currently being used in the RSI process to determine the magnitude in the reduction of risk • Knowledge of CMF’s useful tool in RSA’s, HD15, RSAI and in road design • Various sources available to search for different CMF’s • Number of considerations to be taken into account when using CMF’s

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