As the 20th century comes to a close, the need to understand the number and type of vehicles using our nation's roadways is becoming more and more important. Since the construction of paved roads, we have struggled with ways to record vehicular movement. Not only is this information required for proper design of roadways, but also new intelligent transportation systems (ITS) require real-time knowledge of traffic movement to be effective. Protection of our nation’s aging infrastructure requires detailed understanding of the number, type, and weight of the vehicles using roads and bridges. With the movement toward design-build highway projects and warranties on performance, accurate measurement of vehicular movement is required to ascertain if the roadway has met or exceeded the design requirements.
New state and federal initiatives, many of which concern the protection of the environment, require detailed traffic information. These needs and others strain available resources within the industry, pushing technology to develop better, faster ways to accurately measure and record vehicular data and transmit this information reliably to where it can be safely analyzed. As the need for highway traffic monitoring grows, public appreciation of the problems in this area remains poor. In general, the public believes that monitoring should be relatively easy and does not understand either the importance or the cost. Because public perception drives legislative decisions, the lack of support has created a crisis in state highway agencies across the nation as staff resources are constrained.
Although the burden to build new highways lessens, state highway agencies are desperately trying to maintain the existing infrastructure in a safe condition and at the same time provide the level of service that highway users have come to expect. None of these things can be accomplished without understanding how highways are used. With this in mind, we take a brief glance at the state of the art and the practice and a look to the future of highway traffic monitoring. What will the 21st century bring? It is hard to say, given the leaps and bounds that technology has taken since the invention and mass distribution of the computer. But as we move into this new era, one thing can be said with certainty: the need for highway traffic monitoring will grow, and as necessity is the mother of invention, new and creative ways will be found to approach this problem.