Memorandum - Safety | Federal Highway Administration. Download Version. PDF [8. 2 KB]US Department of Transportation. Federal Highway Administration. Subject: ACTION: AASHTO Roadside Design Guide 4th Edition. Date: June 2. 6, 2. From: Tony Furst, Associate Administrator for Safety. In Reply Refer To: HSSTTo: Division Administrators. Safety Field. Federal Lands Division Engineers. The AASHTO Roadside Design Guide (RDG) 4th edition was published in October 2. The Office of Safety is distributing one copy to most FHWA field offices, with larger offices receiving two copies. The purpose of this memo is three- fold: Reiterate the status of the RDG for FHWASummarize significant changes in the RDG 4th edition. Add Frequently Asked Questions to our website. Status of the RDG for FHWAPlans and specifications for projects on the National Highway System (NHS) must provide for facilities, including the roadsides that are conducive to safety. The RDG is included in the FHWA Policy and Guidance Center (PGC) as “guidance” for use when designing highway projects and addressing roadside issues on the NHS. The first edition of the RDG was adopted by the FHWA through the Federal Register, effective July 2. ![]() States should use to develop roadside safety design policies. This memorandum supersedes the FHWA memorandum dated July 1. RDG adoption. Each State highway agency should have a written policy for designing roadsides that incorporates wide clear zones, traversable drainage structures, and breakaway sign and lighting support structures in new construction and reconstruction and, to the extent practicable, in 3. R- type projects. The roadside policy should also describe how other hazards may be relocated, modified, shielded, or delineated. The provisions of the AASHTO RDG should be used by each State to develop their roadside policy document. Action. Each Division Office should: 1) encourage their State highway agency to have a written roadside policy, and 2) review their State’s conformance with the RDG 4th edition. Where substantial differences are found, the State should be encouraged to update their practices to be in line with the current RDG. ![]() Directors of Field Services. John R. Baxter, Associate Administrator for Infrastructure, (HIF- 1)Jeffrey A. Lindley, Associate Administrator for Operations, (HOP- l)Fred R. Wagner, Chief Counsel. HCC- 1)Attachments. Attachment No. 1 is a summary of major changes between the 4th edition and earlier editions. Attachment No. 2 is a compilation of questions and answers. Attachment #1. Significant changes in the RDG 4th edition. This section presents a brief outline of changes from the 3rd edition, plus provides additional detail on certain significant issues that may affect State design standards. Chapter 1 – An Introduction to Roadside Safety. Roadside crash statistics are updated. AASHTO Strategic Plan for Highway Safety and the NCHRP Report 5. Series of guides are referenced to help States in their efforts to reduce crash injuries and fatalities. References FHWA hardware eligibility letter Web Site for additional information on the eligibility of crash tested hardware for reimbursement under the Federal- aid Highway program. Chapter 2 – Economic Evaluation of Roadside Safety Editorial updating only. The Roadside Safety Analysis Program (RSAP) is being re- written under NCHRP Project 2. Errata to Roadside Design Guide, 4th Edition RSDG-4-E5 3 July 2015 Page Existing Text Corrected Text G-1 Definition of Clear Zone reads: “The total roadside border. The AASHTO online bookstore. AASHTO technical standard, design and construction specification, and design guides for the construction, design and maintenance of. ROADSIDE DESIGN GUIDE, 4th Edition 2011 AASHTO - Subcommittee on Design June 11, 2012. Portland, Maine. Keith A. Cota, New Hampshire Department of Transportation. Roadside Safety Analysis Program Update” and will be available on- line when completed. Chapter 3 – Roadside Topography and Drainage Features“Clear- Zone” terminology coordinated with AASHTO Green Book. Clear- Zone for auxiliary lanes defined. Curb discussion moved to Chapter 5. Chapter 4 – Sign, Signal, and Luminaire Supports, Utility Poles, Trees, and Similar Roadside Features. Update breakaway discussion re: AASHTO Manual for Assessing Safety Hardware (MASH) – pickup test, windshield damage, roof crush. Under NCHRP Report 3. Now, the MASH provides thresholds for deflection and penetration of the windshield and the occupant compartment of the test vehicle. Cites MUTCD breakaway requirement. The MUTCD requires all signs within the clear zone of all roads open to public travel in the United States to be mounted on breakaway/yielding structures, or be shielded with a crashworthy barrier. All new installations of signs on any road must be breakaway or shielded if located within the clear zone. Retrofits of non- breakaway supports are required by January 1. Recommends breakaway devices in urban areas as run- off- road crashes tend to occur at times of reduced pedestrian traffic. Notes that MUTCD requires that breakaway supports housing electrical components utilize electrical disconnects to reduce the risk of fire and electrical hazards after impact by a vehicle. Emphasizes the need for omni- directional supports at intersections and other locations where traffic approaches from various directions. Discusses high mast lighting supports and traffic signal supports. ![]() The AASHTO Roadside Design Guide (RDG) 4th edition was published in October 2011. The Office of Safety is distributing one copy to most FHWA field offices, with. Design Standards. Title 23 USC 109 provides that design standards for projects on the National Highway System (NHS) must be approved by the Secretary of the U.S. Frequently Asked Questions: Barriers, Terminals, Transitions, Attenuators, and Bridge Railings. FHWA barrier guidance is contained in the AASHTO Roadside Design Guide. To purchase a copy of the Roadside Design Guide, 4th Edition, visit the AASHTO Bookstore at https://bookstore.transportation.org. Steel sign structure. truss structures. commonwealth of pennsylvania. department of transportation. lbs 0 structure & dms standard weatherproof. chief bridge engineer. These are generally not considered for breakaway hardware but there are certain situations on high- speed roads where relocation of hardware or shielding should be considered. Refers to NCHRP Report 5. Volume 8 for dealing with utility poles. Chapter 5 – Roadside Barriers. References MASH and AASHTO FHWA Joint Implementation Plan. For details on the Implementation Plan, please see the AASHTO website: https: //bookstore. DB=3. Discusses motorcycles and barrier design. While various treatments are used in Europe, the U. S. is studying the extent and nature of motorcycle crashes into barriers. If U. S. crash experience shows that the European treatments can have a significant effect on the reduction of crash severity, then the treatments will need to be evaluated to see if they will adversely affect barrier performance under current MASH criteria. Links to Task Force 1. A Guide to Standardized Highway Barrier Hardware’ (Barrier Hardware Guide) and FHWA Eligibility Letters. The Barrier Hardware Guide is available at: http: //www. New W- beam systems, including MGS and the proprietary 3. These are covered in detail in our May 1. Zone of Intrusion (ZOI) concept. The ZOI is the region measured above and beyond the face of a barrier system where an impacting vehicle or any major part of the system may extend during an impact. The amount of intrusion is related to the height and profile of the barrier, as well as the vehicle size, speed, and angle of impact. For Test Level 4 and higher, the designer should try to accommodate this additional clearance for ZOI. Revised discussion of guardrail behind curbs. Two designs of 3. Runout lengths reduced for barrier design. This results in generally shorter “length of need” for barriers. Guardrail posts in rock or mow strips. Strong- post guardrail systems require the posts to be able to push through the soil upon impact. The RDG offers designs for leave- outs when placing posts in pavement or rock. Upgrading existing systems revised. The old RDG three inch +/- tolerance allowed guardrail that was much too low to remain in place. W- beam guardrail that is less than 2. While new installations must be at least 2. See the FAQs for guidance on raising guardrail. Chapter 6 – Median Barriers. This was introduced in the 2. Chapter 6 and is incorporated into the 2. Edition. Please note that Figure 6- 1 in early printed editions of the 2. RDG show the incorrect graphics. Download the errata from the AASHTO Bookstore website. Details generic low- tension and proprietary high- tension cable barriers. Discusses median terrain effects on barrier performance and location. Further information on placing cable barriers on sloping terrain is available in the final report from NCHRP Project 2. FHWA guidance. All new and existing median barriers can be found in the Hardware Barrier Guide: http: //www. Chapter 7 – Bridge Railings. Discusses MASH, and the AASHTO Load, and Resistance Factor Bridge Design Specifications (LRFD). The LRFD require 4. NCHRP Project “Guidelines for Design and Shielding of Bridge Piers” will develop warranting criteria for these barriers, transition, and approach guardrail. Incorporates “Protective Screening at Overpasses” which was once a separate AASHTO guide. References Task Force 1. Bridge Rail Guide. All new and existing bridge railings can be found in the TF1. Bridge Rail Guide: http: //guides. Rail. Guide/index. Chapter 8 – End Terminals. Discusses grading in advance of and behind terminals. Lists numerous new terminals and crash cushions. All new and existing end terminals can be found in the Barrier Hardware Guide: http: //www. Includes a table of Comparative Maintenance Requirements. Chapter 9 – Work Zone Devices. Generic and Proprietary Portable Concrete Barrier designs enumerated. Includes a discussion of how you can reduce deflection by pinning barriers and other treatments. Excellent discussion of water filled barriers vs. Chapter 1. 0 – Roadside Safety in Urban or Restricted Environments. Describes “enhanced lateral offset” for use in urban areas where conventional clear zone widths are impractical. Research into crashes show that an enhanced lateral offset of 4 feet minimum, 6 feet desirable, will address most crashes in urban areas. 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. This is a critical point to get across to designers. The 1. 5 foot minimum distance behind a curb is and operational offset intended to accommodate truck mirrors and open car doors. It should not be used as a “clear zone.”Chapter 1. Mailboxes. Includes a discussion of heavy and hazardous mailboxes including vandal proof boxes and secure, locked mailboxes where they should not be placed. Advocates the use of lightweight plastic designs. Includes strategies for getting homeowners to allow replacement of hazardous rural mailboxes. Chapter 1. 2 - Roadside Safety on Low- volume Roads and Streets.
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