U.S. Department of Transportation
Federal Highway Administration
1200 New Jersey Avenue, SE
Washington, DC 20590
202-366-4000
The scanning team was impressed by a novel approach to exploring long-range solutions for meeting future highway demands in the Netherlands. The government integrated long-term perspectives with short-term test projects and demonstrations through a cooperative, split-funded program with industry called “Roads to the Future.” The intent of this program was to examine road surfaces of the future and to develop demonstrable concepts for tomorrow's road surface. The agency's softer goals were to stimulate out-of-the-box thinking in both the agency and Dutch companies.
The government established three formal areas of interest: modular road surfaces, smart road surfaces, and energetic road surfaces. The criteria for the Modular Road Surface Program called for a surface that was prefabricated, noise reducing, easy to apply, and easy to remove. Private contractors were invited to offer solutions, no matter how unconventional. The tremendous response surprised the agency. Four techniques resulted in demonstrable projects in which the surfaces were placed on a freeway ramp. The scanning team proposes that one of these products be demonstrated in the United States.
Because of the expense and logistics associated with field-testing of lane markings (stripes), Germany has developed a laboratory facility for accelerated lane marking evaluation. This facility is capable of evaluating tape, temporary paint, and permanent paint markings. Since the facility began testing in 1989, nearly 2,000 materials have been tested. This specification can be found in CEN 13197.
The accelerated procedure consists of a wheel (8 meters in diameter) with spokes affixed with a rectangular test plate at the end. Each test plate is coated or painted as appropriate with pavement stripe material. As the test wheel rotates, the plates come in contact with up to six tires that apply pressure to each plate. The protocol describes the number of cycles and the environmental condition that the striping material is exposed to during the test. At predetermined cycles, the plate is removed and evaluated using various functional tests.
The scanning team recommends consideration of establishing a central test facility in the United States with an accelerated test apparatus for assessing the durability of pavement markings. With a basis in the proven German procedure, the new facility could include environmental controls to simulate various climates.
The scanning team has identified several key processes worthy of additional examination. They include the EU, the British HAPAS program, and the French Charter for Innovation. Each has potential merit for implementation in the United States. The team was not able to clearly comprehend the full nature of the effort, the agreements, or the potential impact this may have on selling and procuring products. While the United States is moving toward performance specifications, no formal national program or process is in place to coordinate and manage such a movement.
European public road agencies have faced many of the staff and funding cutbacks experienced by State DOTs. Also, they seek both innovation and cost-effective execution of their maintenance operations. All four countries the scanning team visited have experience with functional (performance-based) maintenance contracts. The United Kingdom is planning to award these contracts solely on quality. The Netherlands is working almost exclusively with these types of contracts and has moved to the second generation of specification. In Denmark, municipalities are beginning to use 10-to-15-year functional contracts for pavement surface renewal and restoration.
The transfer of work items associated with functional maintenance contracts includes the transfer of roles and responsibilities to the private contractor. This has an impact on the application of standards, material selection, mix designs, pavement design, quality control and assurance techniques, warranties, and independent government assessment of product value and safety.
The scanning team recommends that guidance be provided to help materials and pavement engineers supply State DOTs with rational approaches to addressing noise in pavement design, mix design, construction, and maintenance. This and other scans have identified noise generated in the highway environment as a problem of significant concern in Europe requiring innovative and sometimes expensive solutions. While U.S. DOTs have established procedures for designing and installing noise walls, only a few have addressed noise attributed to pavement type selection, material selection, and construction and maintenance techniques. Several DOTs are now addressing this problem by using modified pavement surface texturing such as diamond grinding or longitudinal tine texturing, or modified mixes such as crumb rubber, SMA, or open-graded asphalt friction courses as noise-attenuating surfaces.
Drivers' expectations and those of abutters to the highways are different in Europe than they are in the United States. As increasing numbers of State DOT material and pavement engineers consider noise issues, however, a more rational approach to pavement and mix design is needed to address the issue.
The scanning team identified numerous products, specifications, and tests that the European countries are using or developing that may be of interest to State DOT engineers in the United States. For a select number of these, the team believes that the logical step is to collect additional European background information. After the information is reviewed, potential benefits should be identified and compared to U.S. practice. Finally, a plan should be developed for possible introduction and evaluation in the United States of select items. Items the team believes have the most potential for U.S. use include the following:
Concrete pavement advancements
U.K. thin surface friction treatments (HAPAS approved)
External enclosures of bridges
U.S. demonstration of pre-fabricated, rolled-out, noise-reducing pavement
Torque bond test
Automated raveling assessment
Microscopy
Wet pressure aging vessel
Polymer content testing
Pulse thermography
Cold-in-place recycling functional specifications
Danish and German orthotropic bridge deck waterproofing
Low-temperature asphalt
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