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Status of the Roadside Design Guide Update

Status of the Roadside Design Guide Update. AASHTO Subcommittee on Design July 19-23 2009 Indianapolis, Indiana . Keith A. Cota, New Hampshire Department of Transportation. Roadside Design Guide. Update Objectives Research Studies Schedule for Completion. Presentation Overview.

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Status of the Roadside Design Guide Update

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  1. Status of the Roadside Design Guide Update AASHTO Subcommittee on Design July 19-23 2009 Indianapolis, Indiana Keith A. Cota, New Hampshire Department of Transportation

  2. Roadside Design Guide

  3. Update Objectives Research Studies Schedule for Completion Presentation Overview

  4. Statistics Updated Incorporated Latest Research Resolved Conflicts related to Clear Zone (NCHRP 20-7, Task 171) within AASHTO Documents Clear zone Clear recovery area Horizontal clearance Lateral offset Update Objectives

  5. Minimum Lateral Offset vs. Clear Zone Update Objectives

  6. Reduced listing of hardware by referencing AASHTO-AGC-ARTBA Task Force 13 Report, “A Guide To Standardized Highway Barrier Hardware” http://aashtotf13.org Update Objectives

  7. Referenced Acceptance Letters from FHWA’s Office of Safety http://safety.fhwa.dot.gov/roadway_dept/ road_hardware/index.htm Added Reference for Updated Crash Test Criteria Under MASH and FHWA/AASHTO Implementation Plan Update Objectives

  8. New chapter on Low Volume Roads, including guidance on: Clear zone Drainage placement Slope and ditch cross-sections Barriers (TL-2) Sign supports Utility pole placement etc. Update Objectives

  9. Updated chapter for Urban Areas, including guidance on: clear zone lateral offset (4-6 ft) landscaping (including median applications) sidewalk placement slope and ditch cross-sections sign supports utility poles placement traffic signals mailbox locations etc. Update Objectives

  10. Urban rights-of-way are often extremely restricted, limiting the applicability of clear-zone practice – even in suburban-to-urban transitions. Urban Chapter Objectives

  11. Urban Chapter Landscape Buffer (Planting Strip) Configuration

  12. Update Objectives • RSAP (Roadside Safety Analysis Program) • Update will maintain current RSAP program • Intent to supplement at time of completion of NCHRP 22-27, “RSAP Update,” currently under contract • Anticipated completion – 2010 or sooner?

  13. Update Objectives • Technical Assistance through NCHRP 20-7, Task 240, “Update of AASHTO Roadside Design Guide” • Contract with King Mak • Provide technical assistance, research overview, and chapter consistency review

  14. Research Studies NCHRP Project 22-17 – “Recommended Guidelines for Curbs and Curb-Barrier Combinations” NCHRP 22-19 “Aesthetic Concrete Barrier and Bridge Rail Designs” NCHRP 16-04 “Design Guidelines for Safe and Aesthetic Roadside Treatments in Urban Areas” NCHRP 22-18 “Crashworthy Work Zone Traffic Control Devices” NCHRP 20-7 (196) “Development of a Guide to Crashworthy Bridge Rail Systems” NCHRP 16-04 “Median Intersection Design for Rural High-Speed Divided Highways”

  15. Research Studies • NCHRP 17-13 “Strategic Plan for Improving Roadside Safety” • NCHRP 20-7 (171) “Guidelines for the Selection of Cable Barrier Systems” • FHWA Memoranda on: • “Guidelines for the Selection of W-Beam Barrier Terminal” • “High Tension Cable on Slopes” • “Design Considerations for Large Trucks” • Midwest Pooled-Fund States Study “Development of Guardrail Treatments at Intersecting Roadways”

  16. Schedule • Schedule for Adoption • Final chapter reviews and Technical Committee balloting at September 2009 meeting in Delaware • Ballot to SCOD in Fall 2009 • TCRS to address SCOD ballot comments, Sept 2010 (or sooner) • Ballot to SCOH in Fall 2010 (or sooner)

  17. AASHTO Subcommittee on DesignIndianapolis, Indiana July 19-23, 2009 AASHTO Manual for Assessing Safety Hardware (MASH) Technical Committee on Roadside Safety 17

  18. Background 1962: HRCS Circular 482 – one-page document, specified vehicle mass, impact speed, and approach angle for crash tests 1973: NCHRP Report 153 – 16-page document, based on technical input from 70+ individuals and agencies and a special ad-hoc panel 1978: TR Circular 191 – addressed minor issues 1980: NCHRP Report 230 – 36-page document, brought procedures up to date with available technology and practices, updated the evaluation criteria 1993: NCHRP Report 350 – Comprehensive update of 230 2009: Manual for Assessing Safety Hardware (MASH) 18

  19. MASH Summary of Changes Test matrices and conditions Test installation Test vehicle specifications Evaluation criteria Test documentation In-service performance evaluation 19

  20. Small car impact angle (20 degree to 25 degree). Impact speed for single unit truck test (80 km/h [50 mph] to 90 km/h [56 mph]). Impact angle for terminals and crash cushions (20 degree to 25 degrees). Gating terminal/crash cushion (Reduce angle from 15 degrees to 5 degrees). Mid-size car test (Add 1500A test vehicle for staged impact attenuation devices). Test Matrices and Conditions 20

  21. Test Matrices and Conditions Barrier Testing Heights (Establish max. for small vehicle and min. height for pickup test) Critical Impact Points (CIPs) for reverse direction impacts TMA optional tests to mandatory (Define max/min truck weight, control ballast shifting and vehicle braking) Variable message sign and arrow board trailers (Require same test criteria as TMAs) 21

  22. Support structures and work zone traffic control devices (Add light truck test in addition to the small vehicle testing criteria) Longitudinal channelizing barricades (Add new category and recommended test matrix) EDR data collection (Provide data on impact conditions and accelerations from vehicle) Test Matrices and Conditions 22

  23. Test Installation Soil Condition (soil type, gradation, compaction and density) Embedment of Posts (not necessary with reporting of soil conditions) Components (provide documentation of components used) Installation Lengths (document length of test installation) 23

  24. Test Vehicles Test vehicles (change small vehicle and pickup) Single unit truck mass (from 18000 # to 22000 #) Light truck test vehicle (Min. c.g. height of 28 inches) Vehicle age (six years older or less) Truck box attachment (limit detachment, reduce inconclusive testing results) Vehicle damage (document external vehicle crush damage using NASS procedures) Crushable nose characteristics (develop updated surrogate vehicle testing from 1981 Volkswagen Rabbit) TMA support vehicle (Report maximum weight of support vehicle) 24

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  26. Evaluation Criteria Occupant risk (Modify calculations for Occupancy Impact Velocity and Ridedown Acceleration with vehicle yawing) Windshield damage (Provides more quantitative criteria; apply criteria to structural support devices the same for work zone devices) Occupant compartment damage (Set objective criteria) Marginal pass (Strictly pass or fail criteria results) Maximum roll angle (Roll and pitch angle at 75 degrees) Exit conditions (Report lane intrusions and exit angle with exit box criteria) Vehicle rebound for crash cushions (reporting criteria) 26

  27. In-Service Evaluation Encourage in-service evaluation to demonstrate satisfactory field performance. Pool resources (partnering) between State proprietary device manufacturers. Disseminate information through resource channels like National Technical Information Services (NTIS), FHWA regional resource centers, and State pooled fund consortiums. Consider the establishment of new national center on in-service evaluation. 27

  28. Full Scale Crash TestsUnder NCHRP 22-14(02) Conducted several full-scale crash tests of existing hardware, including: Strong Post W-Beam System Midwest Guardrail System New Jersey Shaped Concrete Barrier F-Shape temp. concrete barrier with 3-loop connection Iowa Transition Tangent Guardrail terminal New Jersey Shaped Concrete Barrier (32 inches), failed TL-4 under MASH 28

  29. All highway safety hardware accepted using criteria contained in NCHRP 350 may remain in place and may continue to be manufactured and installed. Highway safety hardware accepted using NCHRP Report 350 criteria is not required to be retested or recertified using MASH criteria. AASHTO/FHWA Joint Implementation Plan 29

  30. If highway safety hardware that has been accepted by FHWA using criteria contained in NCHRP Report 350 fails testing using MASH criteria, AASHTO and FHWA will jointly review the test results and determine a course of action. Upon adoption of MASH by AASHTO, any new highway safety hardware not previously evaluated shall utilize MASH for evaluation and testing. MASH Implementation 30

  31. Any new or revised highway safety hardware under development at the time the MASH is adopted may continue to be tested using the criteria in NCHRP 350. However, FHWA will not issue acceptance letters for new or revised highway safety hardware tested using NCHRP Report 350 criteria after January 1, 2011. MASH Implementation 31

  32. Agencies are encouraged to upgrade existing highway safety hardware that has not been accepted under NCHRP Report 350 or MASH: during reconstruction projects, during 3R projects, or when the system is damaged beyond repair. MASH Implementation 32

  33. MASH Implementation Highway safety hardware not accepted under NCHRP Report 350 or MASH with no suitable alternatives available may remain in place and may continue to be installed. 33

  34. Contact Information Keith A. Cota, Chairman AASHTO Technical Committee on Roadside Safety New Hampshire DOT Hazen Drive, PO Box 483 Concord, NH 03302-0483 Tel: 603-271-1615 Email: kcota@dot.state.nh.us 34

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