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1. Status of the Roadside Design Guide Update AASHTO Subcommittee on Design July 19-23 2009 Indianapolis, Indiana
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2. Roadside Design Guide 2
3. Update Objectives
Research Studies
Schedule for Completion 3
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 4 Removinig Horiz Clearance
In green book used lateral offset of 18 inches meets clear zone
Going with lateral offset for urban areas and not referencing this as “clear zone”
Urban chapter, lateral offset behind curb and gutter for non-breakaway type devices, of 4 feet (min) to 6 feet (desirable)
Green book will still say 18 inches minimum for opening car doors and for mirrors on trucks
Based on Urban research study through NCHRP
Removinig Horiz Clearance
In green book used lateral offset of 18 inches meets clear zone
Going with lateral offset for urban areas and not referencing this as “clear zone”
Urban chapter, lateral offset behind curb and gutter for non-breakaway type devices, of 4 feet (min) to 6 feet (desirable)
Green book will still say 18 inches minimum for opening car doors and for mirrors on trucks
Based on Urban research study through NCHRP
5.
Minimum Lateral Offset
vs.
Clear Zone
5 Examples of the urban landscape that the designer has to take into account (as opposed to clear zone in rural areas)
Where is offset measured from? Illustrates issues, vagueries
Bench, light pole, large bear – Examples of the urban landscape that the designer has to take into account (as opposed to clear zone in rural areas)
Where is offset measured from? Illustrates issues, vagueries
Bench, light pole, large bear –
6. Reduced listing of hardware by referencing AASHTO-AGC-ARTBA Task Force 13 Report, “A Guide To Standardized Highway Barrier Hardware”
http://aashtotf13.org
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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 7
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. 8 Barriers of TL-2, are looking at a lower functioning barrier – risk assessment of needs, benefit/cost analysis for barriers and terminals
Maybe some add’l research is needed to determine appropriate barrier for low-volume roads – concrete versus cable
All questions not answered, but some guidance is provided on what you should cnosider
More consistent with VLVLR from Green Book committee, run off road, barrier needs and barrier warrants….Barriers of TL-2, are looking at a lower functioning barrier – risk assessment of needs, benefit/cost analysis for barriers and terminals
Maybe some add’l research is needed to determine appropriate barrier for low-volume roads – concrete versus cable
All questions not answered, but some guidance is provided on what you should cnosider
More consistent with VLVLR from Green Book committee, run off road, barrier needs and barrier warrants….
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. 9 Updated using NCHRP 16-04 “Design Guidelines for Safe and Aesthetic Roadside Treatments in Urban Areas”
Updated using NCHRP 16-04 “Design Guidelines for Safe and Aesthetic Roadside Treatments in Urban Areas”
10. Urban rights-of-way are often extremely restricted, limiting the applicability of clear-zone practice – even in suburban-to-urban transitions. 10 Demonstrating different practices out there…..
Left photo has light poles very close to roadway, just behind curb
Right photo has poles set backDemonstrating different practices out there…..
Left photo has light poles very close to roadway, just behind curb
Right photo has poles set back
11. Urban Chapter Landscape Buffer (Planting Strip) Configuration 11 Another demonstration of streetscape designers deal with – some trees are set back a couple feet, others are not…..
Another demonstration of streetscape designers deal with – some trees are set back a couple feet, others are not…..
12. 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? 12
13. 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 13
14. 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” 14
15. 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” 15
16. 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) 16
17. AASHTO Subcommittee on DesignIndianapolis, Indiana July 19-23, 2009 AASHTO Manual for Assessing Safety Hardware (MASH)
Technical Committee on Roadside Safety
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)
19. MASH Summary of Changes Test matrices and conditions
Test installation
Test vehicle specifications
Evaluation criteria
Test documentation
In-service performance evaluation
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).
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)
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)
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)
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)
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)
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.
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 TTI is now conducting crash tests under 22-14(03)
Strong post w-beam (steel post, wood block out) – did NOT pass pickup truck for TL-3 under MASH
Likely look to do an in-ervice evaluation study to see if there are other issues with this device….TTI is now conducting crash tests under 22-14(03)
Strong post w-beam (steel post, wood block out) – did NOT pass pickup truck for TL-3 under MASH
Likely look to do an in-ervice evaluation study to see if there are other issues with this device….
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.
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.
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.
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.
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.
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