The intelligent highway has long been a dream of urban planners everywhere. This is a very efficient highway that permits traffic to flow quickly and effortlessly without congestion. While we have been speaking of this mythical highway for decades, only now are we finally beginning to see real but partial implementations. In the meantime, traffic congestion continues to outpace highway construction.
Recent developments in electronics, especially wireless systems, make it possible to build a practical intelligent highway. However, political issues (federal, state, county, and city) as well as high costs have slowed progress with the exception of small pockets of specialized activity.
Furthermore, just as important is the fact that an intelligent highway isn't fully effective without intelligent cars to use it. So while we don't yet have the intelligent highways visualized for cities of the future, we are gradually seeing more and more intelligent devices that improve our transportation system. Under the auspices of the Intelligent Transportation System (ITS), our roads and our cars are gradually evolving to improve our most widely used mode of transportation (see "The ITS Program," p. 104).
Over the past decade, major progress has taken place in the ITS. Massive traffic problems spurred states and cities to solve the problems with new initiatives in intelligent highways and improved public transportation like light rail. U.S. Department of Transportation (DOT) funds have become available to test concepts and pilot projects.
As with anything that's technology driven, unforeseen problems that have major implications have cropped up. For example, with all of the modern conveniences like in-vehicle entertainment and communications systems now available in new automobiles, driver distraction is becoming a serious problem (see "The Distraction Factor," p. 112). This has given rise to a call for local, state, and government regulations on how and when to use such conveniences while driving safely.
For the ITS to become a reality, it will take not only smart highways and an attendant infrastructure, but also a smart vehicle that can work in conjunction with the system. To make these two work together, the ITS equipment must perform several basic functions, including data acquisition, data transmission, control, and vehicle equipment interaction.
The data-acquisition system for the intelligent highway will use different types of sensors to detect the presence and quantity of traffic and weather conditions. Induction loop detectors are widely used today at intersections to provide control to signal lights. These will remain in use, but other types of sensors will be installed at intersections and along roadways. Radar sensors have successfully been installed on overhead structures to detect traffic on multilane highways. Additionally, video cameras in a closed-circuit television (CCTV) system will be employed.
All of the sensor data and video will then be transmitted by wireless means to a control center for the analysis and compilation for its ultimate use. The ITS also envisions using probe or floating vehicles that are sent out into the traffic to further sense both traffic and road conditions.
Once the data has been collected, analyzed, and formatted, it will again be transmitted by wireless means. Traffic and road-condition data can be transmitted by standard broadcast AM, FM, and TV stations, or by radio data systems (RDSs), the new digital satellite radios.
The ITS control center would be set up to acquire, process, and communicate the collected information. The system would verify the information's accuracy, reconcile conflicting data, and prepare a set of traffic-condition data for transmission. The control center would additionally monitor critical areas of roadways and intersections with CCTVs, as well as display this information. Large traffic maps of the complete area covered would be maintained so operators could continuously observe the status of major roadways. Emergency and rescue operations could be initiated and coordinated.
Control centers would develop wireless messages for transmission to display signs or to supply adaptive control to traffic signals, ramp meters, and other control methods. Ultimately, control centers may even transmit commands to provide remote control of individual vehicles.
Of course, considerable data acquisition will take place inside the vehicle too. A variety of sensors will determine vehicle speed and location. An on-board global positioning satellite (GPS) system will provide the driver with current location information that also can be transmitted to a control or emergency center. Sensors might signal the number of passengers in the car, vehicle orientation (tilted, upside down, and so forth), or engine and chassis data that helps assess and diagnose the physical condition or maintenance status of the vehicle.
Data transmission from the vehicle will occur via cellular telephone. With the data transmission capabilities of the newer and forthcoming 3G cell phones, this seems like the most practical, realistic, and economical method of sending vehicle data.
As for the vehicle equipment, it will consist of sensors, processors, and communications equipment that will interact with the infrastructure systems. Most of this equipment has already been developed and is being deployed in upscale automobiles. Generally known as telematics, this subsystem consists of a built-in cell phone with sensors and control capability.
A key part of the system will be the GPS receiver. It will supply location information that can be transmitted via the cell phone. Additionally, the GPS system will be implemented in conjunction with a processor and digitized maps that will provide on-screen maps for driver navigation. The GPS location information also can be transmitted for the purpose of locating the vehicle in the event of an accident. Furthermore, most new telematic systems automatically dial emergency services when an airbag deploys.
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