FHWA Resource Center Helps Federal Lands Highway Division Develop Context Sensitive Roadway Surfacing Selection Guide
In 2005, the Federal Highway Administration (FHWA) published the Context Sensitive Roadway Surfacing Selection Guide. The guide documents the available options for roadway surfacings and provides a decision-making process to allow consideration of functionality, performance, durability, safety, life-cycle costs, and aesthetics and environmental impacts.
This guide was produced by FHWA's Federal Lands Highway (FLH) Division. The guide presents a review of FLH's Project Delivery Process (PDP) and a proposed roadway surfacing selection process that includes consideration of context sensitivity, to be used in conjunction with the PDP. A CD-ROM titled "Roadway Surfacing Options Photo Album" accompanies this guide. The FHWA Resource Center provided technical assistance in the development of the guide.
Colorado Scenic Byway Project Demonstrates Need for Road Surfacing Guidance
The FLH Division is the primary road builder for the National Park Service, U.S. Forest Service (USFS), U.S. Fish and Wildlife Service, and several other government agencies. The roads constructed or rehabilitated by FLH are generally low to medium volume roads. The FLH's customers, as well as communities, environmental organizations, and individual landowners, are increasingly concerned about the selection of roadway surfacing types—in particular, the riding surface on proposed projects. Often the project stakeholders have difficulty agreeing on a preferred surfacing type because of biases of performance, aesthetics, or other issues.
|The Guanella Pass Scenic and Historic Byway in Clear Creek County, Colorado, is approximately 35 miles from the Denver metropolitan area and follows an old wagon trail that linked the mining towns of Georgetown and Grant.
Such a project example regarding surfacing type and other environmental questions prompted the development of the Context Sensitive Roadway Surfacing Selection Guide. The Central Federal Lands Highway Division (CFLHD) designed the Guanella Pass Road in the Colorado Rocky Mountains for a USFS project. The Guanella Pass abuts a historic Victorian mining district and traverses subalpine forest and alpine tundra. The project also parallels alpine creeks with lakes that compose watersheds, which supply surface water for use by many households.
The Guanella Pass Road project involved substantial environmental controversy provoking the following concerns:
- Upgrade of roadway surface from unbound gravel to various hard surfaces that likely would affect water quality.
- Visual aesthetics of the mountainscape.
- Speeds of vehicles that might affect the recreational use of the road.
The selection process for roadway surfacing pointed to a need for guidance on selecting surfacing materials based on the context of the roadway that was being designed. The CFLHD agreed to test the use of four or five surface types (as test sections) in the initial construction phase of this project for two purposes: to satisfy interested groups, and to protect the various environmentally sensitive areas of the project.
America's Byways: Guanella Pass Road
Guanella Pass Road leapfrogs the steep divide between the South Platte and Clear Creek watersheds, passing through a succession of distinct environments. Thick stands of spruce, fir, aspen, and pine rise along cascading creeks in the lower elevations. Higher up, the streams snake through broad meadows. The road crests well above the timberline, where every spring the fragile tundra thaws and blossoms. This region, once providing work for miners and trappers, now attracts history enthusiasts and nature and recreation seekers.
Resource Center Assists With Proposal Development and Evaluation
The complexities exhibited in the Guanella Pass Road project revealed a critical requirement to provide direction in the selection process for roadway surfacing. In 2002, the FLH Division initiated steps to advance development of a guide through a research contract:
- Research Panel Organized to Lead Project. The panel was responsible for overall project direction and verification of technical merit of materials and for acceptance of the procedures for FLH Division use.
- Technical Personnel Selected to Staff the Panel. The Research Panel included an Environmental Specialist, a Pavement Specialist, a Materials Specialist, and a Technology Transfer Specialist.
- FHWA Resource Center Invited to Provide Technical Assistance. Pavement and Construction specialist Bernie Kuta of the Construction and Project Management Technical Service Team contributed technical assistance with proposal development and the evaluation of the contractor proposals. Kuta also
participated on the panel for the duration of the research contract to advise and share knowledge in pavement and materials, along with offering recommendations in construction processes.
In 2003, a research contract was awarded to Golder Associates, Inc. The contract designated the following tasks:
- Develop a summary list of surfacing options with a matrix of distinguishing characteristics.
- Develop a decision process tree to objectively evaluate the appropriateness of surface types.
- Develop presentation materials for use by designers and environmental specialists for client and public meetings.
- Develop training aids for implementation.
Research Contract Calls for Context Sensitive Roadway Surfacing Selection Guide
- Literature Review and Investigation. Golder Associates delved into common surfacing products such as conventional hot mix asphalt and unbound gravel as well as specialized products such as colored stamped concrete, natural stone pavers, and synthetic polymer emulsions. Over 100 individual roadway surfacing types and subsequent combinations were identified in this phase of the work. The panel tasked the contractor to develop a matrix of characteristics of the most common 75 percent of these surfacing types.
- Standard List (Description) of Characteristics. A standardized format was developed for describing surface characteristics within 11 general topics, each with subtopics (listed below) that vary according to critical aspects of each product. The needs and warrants for each product are intended to be an objective description of the product.
- General Information: Product description, generic and trade names of products, suppliers.
- Application: Typical use, traffic, restrictions on use.
- Design: Typical structural layer coefficient, base requirements, special considerations.
- Construction: Product availability, constituent materials and equipment needed for placement, lane closure requirements, weather-related restrictions, and typical construction rates.
- Serviceability: General performance history, life expectancy and preservation potentials, anticipated ride quality and potential distresses, potential maintenance needs.
- Safety: Skid resistance potential, potential hazards associated with the surface type.
- Environmental Concerns: Raw material sources, short-term impact due to construction process, potential long-term environmental impacts, recyclability, roadway noise, and manufacturing energy usage.
- Aesthetics: Color and texture of finished and worn-in product, description of probable maintenance effects on appearance over time.
- Cost: Approximate unit costs (2004).
- Example projects: (not just by the FLH Division).
- Resources: Further information such as product suppliers or industry associations.
Example project worksheet.
- Prioritization Methodology. The contractor developed a prioritization methodology that incorporated rating these factors in a multiple-step decision matrix that results in objectively ranked suitability of surfacing types for use based on the various project needs. This is not a pavement design methodology, but rather a tool to help select a surface type based primarily on the appearance of the surface material.
- Roadway Surfacing Selection. The FLH Division published the Context Sensitive Roadway Surfacing Selection Guide (Publication No. FHWA-CFL/TD-05-004) in August 2005. The process has been used in 2005 and 2006 to make decisions on several minor projects. Since the procedure can be used in whole or in part on a project, depending on the nature of and the amount of controversy related to the project, the FLH Division is encouraging designers to use the procedure on any type of project.
- Companion Roadway Photo Album. The FLH Division published a companion "Roadway Surfacing Options Photo Album" that provides inservice pictures and details of over 45 surface types. It is available on compact disc (Publication No. FHWA-CFL/TD-05-004a).
- Training. The FLH Division is developing training on the use of the Context Sensitive Roadway Surfacing Selection Guide for environmental managers and project managers within the FLH Program. It is anticipated that the Guide will be useful to other organizations that have to make choices of roadway surfacing materials in the context of environmental controversy.
For more information, contact:
Construction and Contract Administration Engineer
Construction and Project Management Technical
FHWA Resource Center
Pavements Discipline Leader
Federal Lands Highway Division
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