The objective of this research was to develop guidelines for safe and cost-effective practices for resurfacing, restoration, and/or rehabilitation projects. The primary focus of the guidelines will be on two-lane rural roads and should address both the roadway and roadside. In May 2015, the panel decided to include freeways based on feedback from agencies and requested additional funds.
The guidelines should be developed according to the following criteria:
- The guidelines should be based on current knowledge of geometric design elements: their impacts on safety and operations, and the trade-offs between costs and benefits.
- The research should evaluate the need to include FHWA’s 13 controlling criteria as well as other design elements, as appropriate.
- TRB Special Report 214 should serve as a starting point for the guidelines, but should not limit the scope of work. The research should integrate relevant information from documents such as the AASHTO Green Book, Highway Safety Manual, Roadside Design Guide, MUTCD, Highway Capacity Manual, and others.
- The guidelines should apply to projects regardless of their funding source.
- The guidelines should focus on geometric design elements, but should include a discussion of how other pertinent factors (e.g., pavement surface, pavement markings, and road user characteristics) should be factored into the decision process.
- As stated above, the focus of the research is on two-lane rural roads. However, to the extent feasible within the budget and current body of knowledge, the research should include a discussion of how the methodology in the guidelines could be applied to address other roadway classifications (excluding freeways).
- The guidelines should include a discussion of tort liability issues.
Prior to 1976, Federal highway funds could only be used for the construction of new highways or the reconstruction of existing highways. This policy was revised by the Federal-Aid Highway Act of 1976 which allowed state and local highway agencies to use federal aid for resurfacing, restoration, and rehabilitation (3R) projects on existing federal-aid highways. However, in 1976 there were no standards for 3R improvements. Transportation agencies relied on standards for new or reconstructed roadways in the AASHTO Policy on Geometric Design of Highways and Streets
(the “Green Book”), and where the proposed geometric elements were below the AASHTO guidelines on a 3R project, design exceptions or exemptions had to be sought. In response to a provision in the Surface Transportation Assistance Act of 1982, the Secretary of Transportation requested the National Academy of Sciences to study the cost-effectiveness of geometric design standards and recommend minimum standards for 3R projects on existing federal-aid highways, except freeways. The purpose of 3R standards was two-fold: (1) to identify minimum standards for selective geometric elements for which 3R funding could be used to maintain existing highways in an effort to extend their service life and (2) to provide transportation agencies with the ability to make cost-effective improvements to existing highways for selective geometric elements to enhance safety and reduce crashes. The result of this study was TRB Special Report 214: Designing Safer Roads: Practices for Resurfacing, Restoration, and Rehabilitation.
Since 1987, values for many of the design elements within the AASHTO Green Book have been revised, including FHWA’s designated 13 controlling criteria, and the cost of construction and the materials used in construction have changed. Incremental geometric design improvements during resurfacing, restoration, and/or rehabilitation projects can be cost effective and have significant payoffs in safety and operational benefits. Furthermore, with the publication of the AASHTO Highway Safety Manual and other recent publications, additional knowledge is available regarding the relationship of geometric elements and the quantification of crashes and their severities. Given current national trends and legislation, transportation agencies are now expected to better integrate safety concerns into project planning, design, construction, operations, and maintenance.
Task 1. Review literature and current state of knowledge.
Task 2. Review existing 3R guidelines and current practice.
Task 3. Develop work plans.
Task 4. Prepare first interim report.
Task 5. Execute approved work plans.
Task 6. Prepare second interim report.
Task 7. Revise 3R guidelines document.
Task 8. Recommend changes to AASHTO documents.
Task 9. Finalize and test cost-effectiveness analysis tool.
Task 10. Prepare final report and presentation.