1 / 20

Element 1: 4-Step Project Selection Process

Element 1: 4-Step Project Selection Process. Element 1: The Systemic Safety Project Selection Process. Objective. Develop a prioritized list of locations that could benefit from systemic safety countermeasures

verdad
Download Presentation

Element 1: 4-Step Project Selection Process

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Element 1: 4-Step Project Selection Process Element 1: The Systemic Safety Project Selection Process

  2. Objective • Develop a prioritized list of locations that could benefit from systemic safety countermeasures • Prioritized = Risk assessment for future crash; answers to question if all elements are equally at risk. • Location = Specific sites from focus facility type; including segments, curves, intersections, etc. Element 1, Step 2: Screen and Prioritize Candidate Locations

  3. Outcome • An assessment and rating of the focus facility type(s). • Identify locations considered for systemic safety improvements. Element 1, Step 2: Screen and Prioritize Candidate Locations

  4. Data Needs • Location of focus facility type • Signalized intersections • Horizontal curves • Divided corridors • Etc. • Site specific crash information • Severity, • Crash type • Relevant contributing factors • Traffic and geometric information • At minimum, for risk factors • Additional information may be needed for selecting countermeasure Element 1, Step 2: Screen and Prioritize Candidate Locations

  5. Element 1: Step 2 Element 1, Step 2: Screen and Prioritize Candidate Locations

  6. Element 1: Step 2, Task 1Identify Network Elements Analyzed Purpose: • Identify the all locations from the focus facilities • A census, not a sample Resources: • Road and intersection data • Crash data at statewide and regional levels Element 1: Step 2, Task 1

  7. Element 1: Step 2, Task 1Identify Network Elements Analyzed Process: • Identify ALL locations from focus facility type. • Curves & Intersections: identify eligible locations • Segments: • Split corridors into elements with consistent traffic and design characteristics (i.e., cross section) • Identify logical segment endpoints 2.Are risk factors feasible for a systemwide analysis? • Did you notice anything that suggests a need to change risk factors? Element 1: Step 2, Task 1

  8. Sample Segment & Curve

  9. Element 1: Step 2, Task 2Conduct Risk Assessment Purpose: • Document the conditions (i.e., risk factors) at each location selected for analysis. Suggestion • While collecting information about risk factors, consider what data might be needed to assign/select the countermeasure. Element 1: Step 2, Task 2

  10. Element 1: Step 2, Task 2Conduct Risk Assessment Resources: • GIS • Electronic inventories of roadway features and traffic characteristics • Data collected as part of a field review • Archives of as-built plans • Aerial photography/street views • Video logs • Traffic control device inventories • Traffic flow maps Element 1: Step 2, Task 2

  11. Element 1: Step 2, Task 2Conduct Risk Assessment Process: • Record roadway and traffic characteristics for the selected risk factors • Document crash history (particularly severe focus crashes) for each location. Element 1: Step 2, Task 2

  12. Example Data Collected for Segments

  13. Video Logs 1 – Usable Shoulder, Reasonable Clear Zone • Edge Risk Assessment • See photos • Lane Width • Shoulder Width/Type • Posted Speed Limit • Curve Signing • Sample Percent No Passing  2– Usable Shoulder, Roadside with Fixed Objects  3– No Usable Shoulder, Roadside with Fixed Obstacles 13

  14. Aerial Images for Segments • Segment Access Points • Curve – Visual Trap and Intersection     

  15. Aerial Images for Intersections • Skew • Intersection on/near horizontal curve • Railroad crossing • Commercial Development in quadrants

  16. Element 1: Step 2, Task 3Prioritize Roadway Facilities Purpose: • Use risk factors to assess locations’ risk. • Identify top sites considered for countermeasure implementation. Element 1: Step 2, Task 3

  17. Element 1: Step 2, Task 3 Prioritize Roadway Facilities Process: • Prioritize roadway facilities using one of two methods to weight risk factors: • Equal weight to risk factors • Identify the risk factors present for each location • Sum the total number of risk factors for each location • Prioritize locations based on number of risk factors present • Weighted risk factors • Assign relative weights to each risk factor • Calculate a score for each location • Prioritize locations based on total score • Set a threshold (the number of risk factors present or a weighted value) used to identify high-priority candidates. • Flag the locations above the threshold. Element 1: Step 2, Task 3

  18. Example County Segment Prioritization Is the County’s entire system at-risk? • No, about 25% of their miles were determined to be a High Priority Element 1: Step 2, Task 1

  19. Example County Curve Prioritization • Complete census of 504 curves • 32 High Priority Curves (6%) • 138 Curves in Proximity Element 1: Step 2, Task 1

  20. Example County Intersection Prioritization Is the County’s entire system equally at-risk? • No, about 41% of their system is a High Priority Element 1: Step 2, Task 1

More Related