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

Jan 03, 2016

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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 - PowerPoint PPT Presentation
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Page 1: Element 1: 4-Step  Project Selection Process

1Element 1: The Systemic Safety Project Selection Process

Element 1: 4-Step Project Selection Process

Page 2: Element 1: 4-Step  Project Selection Process

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.

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

Page 3: Element 1: 4-Step  Project Selection Process

Outcome

• An assessment and rating of the focus facility type(s).

• Identify locations considered for systemic safety improvements.

3Element 1, Step 2: Screen and Prioritize Candidate Locations

Page 4: Element 1: 4-Step  Project Selection Process

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

4Element 1, Step 2: Screen and Prioritize Candidate Locations

Page 5: Element 1: 4-Step  Project Selection Process

Element 1: Step 2

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

Page 6: Element 1: 4-Step  Project Selection Process

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 16

Page 7: Element 1: 4-Step  Project Selection Process

Element 1: Step 2, Task 1Identify Network Elements Analyzed

Process:1. 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 17

Page 8: Element 1: 4-Step  Project Selection Process

Sample Segment & Curve

8

Page 9: Element 1: 4-Step  Project Selection Process

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 29

Page 10: Element 1: 4-Step  Project Selection Process

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 210

Page 11: Element 1: 4-Step  Project Selection Process

Element 1: Step 2, Task 2Conduct Risk Assessment

Process:1. Record roadway and traffic characteristics for the

selected risk factors2. Document crash history (particularly severe focus

crashes) for each location.

Element 1: Step 2, Task 211

Page 12: Element 1: 4-Step  Project Selection Process

Example Data Collected for Segments

12

Page 13: Element 1: 4-Step  Project Selection Process

13

Video Logs

• 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

1 – Usable Shoulder, Reasonable Clear Zone

3 – No Usable Shoulder, Roadside with Fixed Obstacles 13

Page 14: Element 1: 4-Step  Project Selection Process

Aerial Images for Segments

• Segment Access Points• Curve – Visual Trap and Intersection

146/2011

Page 15: Element 1: 4-Step  Project Selection Process

Aerial Images for Intersections

• Skew• Intersection on/near

horizontal curve• Railroad crossing• Commercial

Development in quadrants

15

Page 16: Element 1: 4-Step  Project Selection Process

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 316

Page 17: Element 1: 4-Step  Project Selection Process

Element 1: Step 2, Task 3 Prioritize Roadway Facilities

Process:1. 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

2. Set a threshold (the number of risk factors present or a weighted value) used to identify high-priority candidates.

3. Flag the locations above the threshold.

Element 1: Step 2, Task 317

Page 18: Element 1: 4-Step  Project Selection Process

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

18

Totals

  # % Mileage %««««« 2 3% 7.4 2%«««« 4 5% 17.9 4%««« 16 21% 75.3 19%«« 28 36% 150.6 38%« 20 26% 108.0 27%

- 7 9% 41.4 10%

77 100% 400.6 100%

Rank Corridor Route # Start End Length ADTADT

RangeRD

DensityAccess Density

Curve CriticalRadius Density

Edge Risk

Totals

Tiebreakers

Edge RiskRD

Density

1 144.01 CNTY 89 CSAH-30 CSAH-30 1.4 480 « « « « « ««««« 3 0.28

2 40.04 CSAH 40NEW LONDON CORP LIM CSAH-2 5.9 450 « « « « « ««««« 2 0.17

3 131.01 CNTY 89 CSAH-30 MNTH-23 0.7 145 « « « « «««« 2 0.29

4 9.02 CSAH 9CR-90 , WILLMAR CORP LIM CSAH-10 5.6 940 « « « « «««« 1 0.14

5 5.06 CSAH 5150TH AVE NW CSAH-29 CSAH-1 10.1 628 « « « « «««« 1 0.14

6 31.02 CSAH 31NEW LONDON CORP LIM MNTH-23 1.6 920 « « « « «««« 1 0.13

7 8.01 CSAH 8RENVILLE COUNTY LINE

LAKE LILLIAN CORP LIM 3.6 750 « « « ««« 2 0.33

8 4.01 CSAH 4 CSAH-8 CSAH-20 6.7 320 « « « ««« 2 0.099 2.05 CSAH 2 CSAH-10 MNTH-23 9.8 385 « « « ««« 2 0.0410 4.04 CSAH 4 CR-98 CSAH-40 2.4 290 « « « ««« 2 0.0011 38.01 CSAH 38 CSAH-40 CSAH-48 2.1 130 « « « ««« 2 0.0012 132.01 CNTY 89 CSAH-8 CSAH-8 2.2 190 « « « ««« 2 0.0013 42.01 CSAH 42 CSAH-7 COUNTY LINE 0.5 120 « « « ««« 2 0.00

14 9.03 CSAH 9 CSAH-10 CSAH-40 , REDWOOD ST 4.9 1,800 « « « ««« 1 0.45

15 25.01 CSAH 25 CSAH-5 USTH-71 3.2 1,315 « « « ««« 1 0.25… … … … … … … … … … … … … … … …… … … … … … … … … … … … … … … …74 1.03 CSAH 1 MNTH-23 PENNOCK CORP LIM 7.0 333   1 0.0375 116.02 CNTY 89 CSAH-3 MNTH-40 7.0 98   1 0.0376 2.04 CSAH 2 ATWATER CORP LIM CSAH-10 6.7 1,018   1 0.0077 28.02 CSAH 28 CSAH-2 COUNTY LINE 2.0 315             1 0.00

Total Stars -- 26 33 34 33 22% That Gets Star -- 36% 46% 47% 46% 31%

Element 1: Step 2, Task 1

Page 19: Element 1: 4-Step  Project Selection Process

Example County Curve Prioritization

19

Complete census of 504 curves32 High Priority Curves (6%)138 Curves in Proximity

Chevrons in PlaceStars # % # %

««««« 0 0% 0 0%«««« 7 1% 2 0%««« 25 5% 4 1%«« 108 21% 1 0%« 250 50% 2 0%- 114 23% 5 1%

504 100% 14 3%

        Crashes           Severe RoR                  

CurveCount

ID Corridor Segment Total Severe K A B C PDO K ARadius

(ft)Length

Curve (ft)ADT

Intersectionon Curve

ChevronsVisualTrap

Rank ProximityChevron

Candidate

1 001A 1.01 CSAH 1 1 - - - - - 1 - - 92 125 50 - - -      2 001B 1.01 CSAH 1 - - - - - - - - - 557 422 50 - - - «    3 001C 1.01 CSAH 1 - - - - - - - - - 823 493 50 - - - «    4 001D 1.01 CSAH 1 - - - - - - - - - 379 359 50 - - -      5 001E 1.01 CSAH 1 - - - - - - - - - 669 456 50 - - - «    6 001F 1.01 CSAH 1 - - - - - - - - - 270 431 50 - - -      7 001G 1.01 CSAH 1 - - - - - - - - - 314 324 50 - - -      8 001H 1.01 CSAH 1 - - - - - - - - - 545 239 50 - - - «    9 001I 1.01 CSAH 1 - - - - - - - - - 459 225 50 - - -      10 001J 1.01 CSAH 1 - - - - - - - - - 368 274 50 - - -      11 001K 1.01 CSAH 1 1 - - - - - 1 - - 318 390 50 - - -      12 001L 1.01 CSAH 1 - - - - - - - - - 267 399 50 - Yes -     Installed13 001M 1.01 CSAH 1 - - - - - - - - - 1,475 345 50 - - - «    14 001N 1.01 CSAH 1 - - - - - - - - - 763 578 130 Yes - - ««    15 001O 1.01 CSAH 1 - - - - - - - - - 859 353 210 Yes - - ««    16 002A 2.02 CSAH 2 1 - - - 1 - - - - 583 752 930 - - - «« Yes Yes17 002B 2.02 CSAH 2 - - - - - - - - - 584 635 930 Yes - - ««« - Yes18 002C 2.02 CSAH 2 - - - - - - - - - 799 665 930 Yes - - ««« - Yes19 002D 2.02 CSAH 2 - - - - - - - - - 963 626 930 - - - «« Yes Yes20 002E 2.02 CSAH 2 - - - - - - - - - 1,234 584 930 - - - «« Yes Yes21 002F 2.02 CSAH 2 - - - - - - - - - 1,188 719 930 - - - «« Yes Yes22 002G 2.02 CSAH 2 1 1 - 1 - - - - 1 938 556 930 - - - ««« - Yes23 002H 2.02 CSAH 2 - - - - - - - - - 1,199 402 930 - - - «« Yes Yes… … … … … … … … … … … … … … … … … … … … … …… … … … … … … … … … … … … … … … … … … … … …… … … … … … … … … … … … … … … … … … … … … …

502 249ZH 249.01 CR 249 - - - - - - - - - 432 301 275 Yes - -   Yes Yes503 249ZI 249.01 CR 249 - - - - - - - - - 814 344 275 - - -   Yes Yes504 249ZJ 249.01 CR 249 - - - - - - - - - 800 685 275 - - - « Yes Yes

Element 1: Step 2, Task 1

Page 20: Element 1: 4-Step  Project Selection Process

Example County Intersection Prioritization

20

Is the County’s entire system equally at-risk?

–No, about 41% of their system is a High Priority

  # %««««««« 0 0%«««««« 0 0%««««« 0 0%«««« 8 11%««« 21 30%«« 33 46%« 9 13%- 0 0%

71 100%Element 1: Step 2, Task 1