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Status of the AASHTO Roadside Design Guide Update

Status of the AASHTO Roadside Design Guide Update. Annual AASHTO Subcommittee on Design Meeting July 25-29, 2010 Columbia, South Carolina. Rod Lacy, P.E. Kansas Department of Transportation. Statistics Updated Incorporated Research Incorporated AASHTO “MASH” document

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Status of the AASHTO Roadside Design Guide Update

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  1. Status of the AASHTO Roadside Design Guide Update Annual AASHTO Subcommittee on Design Meeting July 25-29, 2010 Columbia, South Carolina Rod Lacy, P.E. Kansas Department of Transportation 2010 SCOD Columbia, SC

  2. Statistics Updated Incorporated Research Incorporated AASHTO “MASH” document Referenced safety hardware websites for designer use. RDG Update Objectives 2010 SCOD Columbia, SC

  3. RDG 2010 – Highlights of Changes • Chapter 1 – An Introduction to Roadside Safety • Updated roadside crash statistics • References FHWA Acceptance Letter Web Site 2010 SCOD Columbia, SC

  4. Percent distribution of fixed-object fatalities by object struck, 2008 2010 SCOD Columbia, SC

  5. 1975-2008 2010 SCOD Columbia, SC

  6. RDG 2010 – Highlights of Changes • Chapter 2 – Economic Evaluation of Roadside Safety • Editorial updating only 2010 SCOD Columbia, SC

  7. RDG 2010 – Highlights of Changes • Chapter 3 – Roadside Topography and Drainage Features • “Clear-Zone” terminology coordinated with Green Book • Clear-Zone for auxiliary lanes defined • Curb discussion moved to Chapter 5 2010 SCOD Columbia, SC

  8. RDG 2010 – Highlights of Changes • Chapter 4 – Sign, Signal, and Luminaire Supports, Utility Poles, Trees, and Similar Roadside Features • Update breakaway discussion re: MASH – pickup test, windshield damage, roof crush • Cites MUTCD Breakaway Requirement • Recommends breakaway devices in urban areas 2010 SCOD Columbia, SC

  9. RDG 2010 – Highlights of Changes • Chapter 4 – Continued • Requires electrical quick disconnect devices • Emphasizes the need for omni-directional supports in various locations • Discusses high mast lighting supports and traffic signal supports • Refers to NCHRP Report 500, Volume 8 for dealing with utility poles 2010 SCOD Columbia, SC

  10. RDG 2010 – Highlights of Changes • Chapter 5 – Roadside Barriers • References MASH and Implementation Plan • Discusses motorcycles and barrier design • Links to Task Force 13 Guide to Standardized Highway Barriers and FHWA Acceptance Letters • New W-beam systems, including MGS and the proprietary 31-inch systems 2010 SCOD Columbia, SC

  11. Typ. W-Beam MGS 2010 SCOD Columbia, SC

  12. 5:1 Flare Rate - 65.1 mph - 4440 lbs - 36.8 deg I.S. = 226 kip-ft Eff. Flare Rate = 4.0:1 at 2000P/25 deg/100 kph 2010 SCOD Columbia, SC

  13. LSC-1 2010 SCOD Columbia, SC

  14. Culvert Opening Protection 2010 SCOD Columbia, SC

  15. RDG 2010 – Highlights of Changes • Chapter 5 – Continued • Zone of Intrusion concept • Revised discussion of guardrail behind curbs • Runout lengths reduced for barrier design • Guardrail posts in rock or mow strips • Upgrading existing systems revised 2010 SCOD Columbia, SC

  16. Zone of Intrusion F:\Roadside Safety\Median Barrier\Semi over CMB in Dallas on north tollway.wmv 2010 SCOD Columbia, SC

  17. Zone of Intrusion • When practical, accommodation of ZOI should be considered on new and reconstruction projects. • Generally, narrowing of the roadway (including shoulders) is not recommended on existing high speed facilities to accommodate this additional distance behind the barrier. 2010 SCOD Columbia, SC

  18. LRFD Bridge Pier Protection Requirements Piers within 30 ft. (9m) of traveled way • Design for load equivalent to large truck impact OR • Shield with barrier to prevent impact by truck • <10 Feet – Use 54” (1370 mm) high rigid barrier • >10 ft. (3m) – Use 42” (1070mm) high rigid barrier • RDG recommends LON based on 15 departure angle, then transition to appropriate barrier for facility. 2010 SCOD Columbia, SC

  19. LRFD Barrier Offset Guidelines • Need national risk-based warrants for this criteria that consider: • AADT, • Route Classification, • Bridge Type, • Site Location Details, • Risk vs Benefit of Tall Barrier per LRFD Criteria • Length of barrier for LRFD criteria, etc • More research needed 2010 SCOD Columbia, SC

  20. RDG 2010 – Highlights of Changes • Chapter 7 – Bridge Railings • Discusses MASH and LRFD • Incorporates “Protective Screening at Overpasses” • References Task Force 13 Bridge Rail Guide 2010 SCOD Columbia, SC

  21. RDG 2010 – Highlights of Changes • Chapter 8 – End Terminals • Discusses grading in advance of and behind terminals • Lists numerous new terminals and crash cushions • Includes a table of Comparative Maintenance Requirements 2010 SCOD Columbia, SC

  22. RDG 2010 – Highlights of Changes • Chapter 9 – Work Zone Devices • Generic and Proprietary PCB designs enumerated • Reduce deflection / pinned barriers • Water filled barriers v longitudinal channelizers 2010 SCOD Columbia, SC

  23. RDG 2010 – Highlights of Changes • Chapter 10 – Roadside Safety in Urban or Restricted Environments • Describes an urban clear zone of 4 feet minimum, 6 feet desirable • Urban control zone concept: keep obstacles away from intersections, driveways, speed change lanes • Emphasizes 1.5 foot min lateral offset to obstructions is not a clear zone 2010 SCOD Columbia, SC

  24. RDG 2010 – Highlights of Changes • Chapter 11 - Mailboxes • Vandal proof mailboxes • Secure, locked mailboxes • Lightweight plastic designs 2010 SCOD Columbia, SC

  25. RDG 2010 – Highlights of Changes • Chapter 12 - ROADSIDE SAFETY ON LOW-VOLUME ROADS AND STREETS • New chapter to RDG • Low cost strategies: SIGNING, MARKING, AND DELINEATION • Clear zone • Roadside hardware 2010 SCOD Columbia, SC

  26. RDG Schedule • Schedule for Publication • Final balloting by TCRS Summer 2010 • Ballot to SCOD Summer/Fall 2010 • TCRS to address SCOD ballot comments by Fall/Winter • Ballot to SCOH by Spring 2011 • Publish Update Summer 2011

  27. For additional information please contact: Rod Lacy Kansas Department of Transportation 785-296-3901 rlacy@ksdot.org 2010 SCOD Columbia, SC

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