This month the Federal Highway Administration introduced its Digital Highway Measurement (DHM) System to the road data collection and research communities, and invited proposals for Strategic Highway Research Program (SHRP) projects involving the new technology. The rollout follows a preview of the DHM system at SPAR 2007 in March by Michael Trentacoste, Director of Safety R & D at the FHWA’s Turner-Fairbank Highway Research Center (TFHRC), McLean, VA, where the technology was developed.
The DHM system includes instruments to accurately measure roadway geometry, safety features, pavements and other highway infrastructure conditions. Instruments on the van include lasers and accelerometers, macrotexture lasers, an inertial navigation unit, standard and high-accuracy national differential global positioning systems, and high-definition stereo cameras. All data is fused and synchronized into one record. The vehicle can collect data while traveling at highway speeds, making it possible to conduct tests without disrupting traffic. Post-processing provides automated creation of data files (e.g., plans, cross-sections, signs, roadside features, pavement condition, roadside drainage, etc.) that can be used for asset management, safety analysis, highway planning and design, quality control, safety research, and highway/driver simulations.
In future phases of the project, additional instruments will be tested – cameras that face downward to record data on pavement cracks, potholes and joint conditions, and LIDAR equipment to collect data on roadside hardware, vegetation and terrain. FHWA is also exploring the use of a new type of 3D ground-penetrating radar technology for subsurface evaluations such as locating utilities. This technology can also be used for bridge deck and pavement thickness measurements.
Field test results
FHWA reports its researchers have used the DHM vehicle in several field tests. They worked with the Pennsylvania DOT on a project to research the type, placement and condition of pavement markers for improving road safety in rural areas. The DHM vehicle collected geometry and roadside data on a rolling two-lane road section with multiple curves. Researchers used the collected data to create a model of the roadway in the highway-driving simulator at TFHRC. The researchers observed test participants driving on the actual road with varying types and conditions of pavement markings, then recorded driving data for a similar set of participants operating over the simulated version of the road; researchers were able to correlate the driving behavior in both situations. The FHWA concluded this project significantly improved the ability of researchers to compare real-world roadway data with vehicle simulator data, calling the DHM vehicle instrumental in ensuring that the simulator correctly simulated real-world conditions.
In another experiment, the researchers used the DHM vehicle to collect geometry data for a 19.3-kilometer section of Virginia Route 9. The Virginia DOT plans to use this data to perform an as-built analysis of the corridor.
How to participate
FHWA has initiated a Pooled Fund Project to involve states and other bodies in future development of the system, and in testing new applications. Information on the Pooled Fund Project can be found at www.pooledfund.org, project No. 1038. In addition, the technologies will be made available cost-free to contractor(s) that are awarded the contract with the National Academies of Science/Transportation Research Board (TRB) for road data collection in the Strategic Highway Research Program II (SHRP2). Other vendors will be able to obtain the technologies through a licensing agreement with the small business contractor that worked with FHWA on the project.
For more information contact Liz Simpson, FHWA Office of Safety R & D, tel. 202-493-3260, email [email protected].
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