Driver Safety
A Georgia Tech-designed intelligent traffic system uses radar detectors to alert drivers to highway hazards
A Georgia Tech-designed intelligent traffic system uses radar detectors to alert drivers to highway hazards
GTRI researchers developed a transmitter and messaging system
that can send a wide range of emergency warnings to motorists using
advanced radar dectectors, as well as a general warning to older
detectors don't offer text messages.
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A SWS transmitter on the side of a highway transmits a warning to a dash-mounted advanced radar detector.
"Intelligent transportation systems planned for the future will improve highway safety by providing drivers with information about the hazards ahead of them, but it's going to be years before such systems are implemented," says Gene Greneker, a principal research associate in the Sensors and Electromagnetic Applications Laboratory at GTRI. "The Safety Warning System will provide a sophisticated warning capability today and serve as a steppingstone to the systems of the future."
The key to development of the system was agreement by four leading radar detector manufacturers to use a common technique for sending emergency information and a standard set of warning messages compatible with National Highway Traffic Safety Administration guidelines.
The new generation of "smart" radar detectors includes a built-in liquid crystal display capable of displaying up to 64 characters. When such a detector receives a safety message, it first sounds a special tone to alert the driver before displaying the message. A second message can also be sent and displayed with the first, so the system could both warn of a hazard and tell the driver of a reduced speed limit.
Because the transmitter also sends out microwave signals on the K band, drivers using older radar detectors would still be alerted to a traffic hazard, but could not be told the specific nature of it.
The consortium of electronics companies, known as RADAR, has filed a patent application to protect the technology.
The Safety Warning System offers sophisticated warning capability
today, and is a bridge to future systems, says Tech's Gene Greneker.
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Transmitters would be located on police and other emergency vehicles, and on construction equipment, bridges, existing overhead sign warning systems and other fixed sites. Portable transmitters could also be moved to locations wherever needed.
"Every police car one day will have one of these," Greneker predicts. "When the police officer turns on the blue lights or siren to begin a pursuit or respond to an emergency, the transmitter would send out a message alerting motorists. At an accident site, the officer would use the transmitter to warn oncoming cars."
GTRI has built and tested one transmitter system, and will be building others as part of larger-scale testing. RADAR, which includes manufacturers B.E.L.-Tronics, Ltd.; Sanyo Technica USA, Inc.; Uniden America Corp.; and Whistler Corp., is pursuing efforts to commercialize the transmitter system.
Since 1991, the Federal Communications Commission (FCC) has allowed use of unattended radar transmitters to trigger radar detectors and thereby warn drivers of hazards. Though these "drone" systems cannot broadcast specific warnings, they have been useful for improving highway safety.
"At least two studies have shown that drone transmitters capable of setting off the current generation of radar detectors are effective at slowing traffic in construction zones," says Janice Lee, president of RADAR. "We believe this technology has much untapped potential. Enhanced transmitters, when coupled with 'smart' radar detectors, will let the driver differentiate between various types of road hazards."
The transmitter system -- developed by Greneker and Bruce Warren, with help from the engineering staffs of each of the participating industry members -- broadcasts the safety warning message using a binary encoded modulation technique that is received and displayed by the new K-band detectors.
Because the 64 standard warning messages are preprogrammed and stored in the detector's memory, the simple code is all the receiver needs to determine which message to display. The seven-bit code can be repeated as often as ten times a second, boosting reliability.
"You don't have to transmit every letter of the message, so there is plenty of opportunity to receive the warning," Greneker notes.
Customized warning messages can also be sent using a keyboard and simple computer- based menu system. Messages on unattended systems could be changed remotely through a dial-up system. Programming functions allow the system to broadcast during certain times of the day, to operate only when vehicles are approaching, or to turn themselves on only after sensing a hazard such as a bridge failure or low visibility.
RADAR has petitioned the FCC to allow higher transmitting power that would increase the range of the system and enhance the ability of moving emergency vehicles to broadcast warnings. With present power levels, the system will provide a warning at least one mile ahead of the highway hazard.
Greneker believes the technology developed for radar detectors could also be applied to other wireless communication needs, expanding the market for both transmitter and receiver manufacturers.
Further information is available from Gene Greneker, Sensors and
Electromagnetic Applications Laboratory, Georgia Tech Research
Institute, Georgia Institute of Technology, Atlanta, GA 30332-0856.
(Telephone: 770/528-7744) (E-mail:
gene.greneker@gtri.gatech.edu)
Send all questions and comments to Webmaster@gtri.gatech.edu
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