The Laser RST : Current status

Efficient and well-maintained road systems are necessary for the economic well being of any industrialized country. Maintenance and rehabilitation of existing roads have taken priority over new construction in recent years, thus making information about the condition of road surfaces extremely important. Several methods of gathering this information have been developed worldwide; one of them is Laser Road Surface Tester (Laser RST), which was developed in Sweden in 1981. The Laser RST is a laser-based, computer-automated, non-contact road profilometer system with the ability to collect and simultaneously process data about the road surface. Variables measured include rut depth, unevenness, cracking, megatexture, rough macrotexture, fine macrotexture, crossfall, curves, and elapsed distance. Subjective evaluations are also supported, if desired. Eleven laser rangefinders (LRFs), mounted on the front of the Laser RST van, are the primary components of the data collection system. They scan the road with high-speed, high-resolution distance sampling. The signals from the lasers are sent through signal processing cards (SPCs) and then to a computer inside the van for final processing. Data is stored on floppy disk and printed by an on-board printer. The Laser RST is an extremely complex system but it is also a modular one, making troubleshooting and repair relatively easy, inexpensive, and fast. This paper discusses the various modules available. Variables measured are defined and measurement algorithms detailed. The Laser RST system can be customized to meet specific user requirements quickly and easily.