Safety Assessment Process: DFW Connector
slide 1: Work Zone Performance Management Peer Exchange Workshop
Texas A&M Transportation Institute
May 8, 2013
Atlanta, GA
slide notes:
Saving Lives, Time, and Resources
slide 2: Presentation Outline
- Project Description
- Methods
- Findings
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slide 3: Orientation
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slide 4: Project Description
- 8.4 miles
- Developer: NorthGate Constructors
- $1.02 billion design-build project
- Construction Start: Feb 17, 2010
- Estimated Completion: Summer 2013
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slide 5: Fast Moving, Design-Build Project
"It is a changing landscape. You can drive through there one day and it can change the next," NorthGate spokeswoman Selma Stockstill.
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slide 6:
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slide 7:
![Aerial photo of construction on one segment of the project. A timeline along the bottom indicates work began on this segment in September 2010 and ended July 2011.](images/s7.png)
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slide 8: DFW Connector
- Allowable Mainlane Lane Closures
- Weekdays 8 PM to 6 AM
- Weekends
- Incident Reporting
- Project TMC
- Courtesy Patrol
- Emergency Response
- Action-oriented Culture
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slide 9: Contractor Tracking – Jan 2010
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slide 10: Contractor Tracking – Jul 2010
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slide 11: Methods
- Data
- Historical Crash Records
- In-Construction Crash Records
- TxDOT Traffic Data
- Analysis
- Modified Ohio Procedures
- Injury and Property Damage Only (PDO)
- Expected vs. Observed Crashes
- Statistical Significance
- Field Reviews
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slide 12: Creation of Small Zones
![Map depicting major highways and roads low block range.](images/s12.png)
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slide 13: Monthly PDO Crash Trends
![Chart shows property damage only crashes in the project area by month and year for the period 2007-2010.](images/s13.png)
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slide 14: Monthly Injury Crash Trends
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slide 15: Crash Frequency within Project Limits Q1 2011 from Baseline
Time Period | Injury Crashes | PDO Crashes | Total |
---|---|---|---|
Weekdays | +32% | +174% | +121%* |
Weeknights/Weekends | -27% | +61% | +31%* |
Total | +16%** | +139%*** | +94%* |
* percent change is statistically significant at α =0.10 |
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slide 16: Comparison of Actual and Expected Q1 2011 Project Limit Crashes by Time Period and Severity
![Chart depicts actual and expected crashes and severity. Actual weekday injuries were 44 and expected injuries were 32.5. There were also 148 actual and 54.1 expected PDO incidents during that period. For weeknights and weekends, actual injuries were 9 while expected injuries were 12.3. There were also 39 actual and 24.2 expected PDO incidents during that period.](images/s16.png)
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slide 17: Change in Crashes by Location in Project Q1 2011
Time Period | West Segment | East Segment | ||
---|---|---|---|---|
Injury Crashes | PDO Crashes | Injury Crashes | PDO Crashes | |
Weekdays | +9% | +99%* | +57%* | +260%* |
Weeknights/Weekends | -24% | +9% | -30% | +121%* |
Total | No change | +71%* | +33%* | +217%* |
* percent change is statistically significant at α =0.10 |
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slide 18: Comparison of Actual and Expected Q1 2011 Project Limit Crashes by Location, Time Period, and Severity
![Chart depicts injury and PDO crashes by western or eastern segment.](images/s18.png)
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slide 19: Weekday, West Side Injury and PDO Crashes
![Chart depicts 2010 and first quarter 2011 injury three-year baseline data, injury during data, PDO three-year baseline data, and PDO during data for the west side construction area during weekdays. PDO crashes spiked significantly during the fourth quarter of 2010.](images/s19.png)
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slide 20: Weekday, East Side Injury and PDO Crashes
![Chart depicts 2010 and first quarter 2011 injury three-year baseline data, injury during data, PDO three-year baseline data, and PDO during data for the east side construction area during weekdays. PDO crashes rose significantly above other trends beginning in the second quarter of 2010 and continued to rise throughout the next three quarters.](images/s20.png)
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slide 21: Weeknight/Weekend, West Side Injury and PDO Crashes
![Chart depicts 2010 and first quarter 2011 injury three-year baseline data, injury during data, PDO three-year baseline data, and PDO during data for the west side construction area during weeknights/weekends. PDO crashes are slightly higher than other trends throughout the period.](images/s21.png)
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slide 22: Weeknight/Weekend, East Side Injury and PDO Crashes
![Chart depicts 2010 and first quarter 2011 injury three-year baseline data, injury during data, PDO three-year baseline data, and PDO during data for the east side construction area during weeknights/weekends. PDO crashes spike in the second quarter but decrease steadily through the fourth quarter before rising slightly in the first quarter of 2011.](images/s22.png)
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slide 23: Weeknight/Weekend, West Side Rear-end (RE) and Side-swipe (SS) Crashes
![Chart depicts 2010 rear end crashes, rear end crashes three-year baseline data, 2010 side-swipe crashes, and side-swipe crashes three-year baseline data for the west side construction area during weeknights/weekends. Rear end crashes are a significantly higher percentage of all crashes and rise steadily from the first through third quarters before dropping slightly in the fourth quarter.](images/s23.png)
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slide 24: Weeknight/Weekend, East Side Rear-end (RE) and Side-swipe (SS) Crashes
![Chart depicts 2010 rear end crashes, rear end crashes three-year baseline data, 2010 side-swipe crashes, and side-swipe crashes three-year baseline data for the east side construction area during weeknights/weekends. Rear end crashes as a percentage of all crashes spike in the second quarter, drop, and then spike and rise steadily in the fourth quarter.](images/s24.png)
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slide 25: Comparison of 1st Quarter 2011 Crash Numbers between TxDOT CRIS and Grapevine PD Hard-Copy Reports
![Chart shows that there were 67 injuries in the first quarter for CRIS, 52 for Grapevine, and 44.9 for the baseline. There were 182 PDO incidents in the first quarter for CRIS, 187 for Grapevine, and 76.3 for the baseline. There were 249 total incidents in the first quarter for CRIS, 239 for Grapevine, and 123.1 for the baseline.](images/s25.png)
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slide 26: Field Review
- Observe conditions to understand nature of crashes
- Example observations
- Pavement marking visibility under high sun reflectivity
- Directional lighting
- Lane shifts in/near ends of horizontal curves and ramp merges
- Guide sign placement within 10° cone of vision
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slide 27: Future Directions
- Continuing analysis…next steps
- Associated with active lane closures
- Associated with detour routes
- Comparison of CRIS to In-construction Reports
- Working to meet FHWA's Toward Zero Deaths: Make work zones safer for workers and public
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slide 28: Contact Information
Jason A. Crawford, P.E.
Texas Transportation Institute
(817) 462-0534
jcrawford@tamu.edu
Jerry Ullman, P.E., Ph. D.
Stephen Ranft
Scott Cooner, P.E.
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