Drowsy, distracted, daydreaming. Those "3-D" driving habits can add up to diasaster when careless motorists drift out of their lanes or off the highway. Government statistics show that 40 percent of all U.S. road fatalities each year—more than 18,000 people—result from unintentional lane or road departure.
The problem is spurring automakers and their top suppliers to step up development of a new device that snaps drivers back to reality with all the grace of a rumble strip: lane departure warning (LDW) systems.
These new active safety devices typically use sound or seat vibration to warn drivers whose vehicles are moving out of their lanes. Tested in commercial trucks since 2000, the systems are now poised for introduction on cars, with the 2005 Nissan Infiniti leading the way.
"Now that we're building cars stronger and with more protective devices, such as airbags, the attention is shifting to systems that will prevent accidents in the first place," says Mark Fitzgerald, an analyst for Strategy Analytics (Newton, MA). Fitzgerald, who recently completed a study on LDW systems, predicts that 3.6 million cars worldwide will incorporate such devices by 2010.
Big Rigs Prove the Concept
Valeo, a giant auto supplier with some 130 plants worldwide, adopted technology from California-based Iteris for its LaneVue™ LDW system for the Nissan Infiniti FX 35 and 45 SUVs, as well as the M45 luxury sedan. "The whole system can fit in the palm of your hand," notes James Schwyn, director of R&D for Valeo North America.
The integrated unit mounts between the rear-view mirror stalk and the front windshield, and consists of a CMOS camera, onboard computer, and software. In operation, the camera looks 25m ahead of the vehicle to track lane markings and feeds the information directly into the microprocessor, which combines this data with the vehicle's speed. Using image recognition software and Iteris proprietary algorithms, the computer can then calculate both the distance between the lane marking as well as the lateral velocity to the lane marking.
If the computer determines that the vehicle is moving out of the lane, the system as implemented in the Nissan alerts the driver with an audible buzzer sound as well as an indicator light on the instrument panel. Other alert options are possible as well, depending on the OEM's preference, including a vibrating seat or steering wheel. In applications of the Iteris system on commercial trucks in Europe, the alert mimics the sound of a rumble strip.
In the Infiniti LDW system, the driver temporarily disables the system whenever he or she uses turn signals for an intended lane change. The system will not work if the camera cannot detect lane markings—or if vehicle speed is below 45 mph. There's also a manual cancel switch, so the driver can turn off the device in construction zones or other areas where frequent maneuvers may be needed.
In independent tests on California highways, the Valeo/Iteris LDW was able to pick up road markings—including the raised yellow "Bott's dots"—over nearly 95 percent of the 475 miles traveled.
Says Schwyn, "We have millions of kilometers of experience with these systems, dating back to their first use on heavy trucks in Europe, and the feedback from users has been very positive."
Valeo's LaneVue system debuted on the 2005 Infiniti FX 35 and 45. It features a tiny camera that views the road ahead as well as a processor that calculates the distance between the vehicle and lane markings and the lateral velocity to the lane markings.
Results of a 2004 survey of 140 truck drivers using the Iteris device in Europe and the U.S. found that 93 percent were satisfied or very satisfied with the system. More than 70 percent of the U.S. truck operators surveyed said the system made them safer drivers, and 98 percent said the device can prevent accidents.
"This system has encouraged me to pay closer attention to the lanes," says Bruce Higginbotham, a driver for North Carolina-based Cargo Transporters. "In bad weather and fog, the system is extremely helpful."
Such results prompted Maverick Transportation (Little Rock, AK) to announce in late 2004 that it would install the Iteris system on its national fleet of 1,000 trucks. "This technology will further enhance our efforts to make our highways safer for both our employees and the driving public," says Steve Williams, CEO of Maverick and the current chairman of the American Trucking Association.
Delphi Automotive, which has developed an LDW technology similar to the Valeo/Interis system, also is targeting commercial trucks for its launch later this year—and is testing it with automotive OEMs as well. "We are on a path to more and more active safety systems that will provide drivers will increased information," says Clayton Nicholas, Delphi's product line manager.
A logical next step in the LDW technology, Nicholas adds, could be a "lane keeping" system that would not only alert the driver, but provide some resistance to a car that is moving off the road or into another lane.
Another major supplier—Visteon—is already researching a more complex system that would combine lane departure or lateral drift warning with curve-speed warning. Working with the University of Michigan Transportation Research Institute (UMTRI), Visteon recently completed testing this dual system on a fleet of 11 Nissan Altimas in Michigan. The U.S. Department of Transportation provided part of the funding in the total $20.5 million research project, which involved a random sample of 78 motorists who drove the vehicles for four weeks.
Assistware Technology's SafeTRAC system, now being used on truck fleets, not only warns drivers if they venture into another lane but also calculates an "alertness score," which tracks a driver's lane centering behavior on an ongoing basis.
In the lane departure component of the system, Visteon incorporates technology from Assistware Technology (Wexford, PA) whose SafeTRAC in-cab safety system has been used in heavy trucks for three years. Like other LDW systems, key components include a tiny camera, processor, and software. However, it also includes four radar units mounted in the front fascia. These forward- and side-facing units assess the room that is available on the shoulder for performing a recovery maneuver.
For curb speed warning, theVisteon system incorporates an antenna situated on the car trunk for gathering global positioning system (GPS) data—plus a precise, onboard map database to determine the current vehicle position, the most likely future path, and the geometry of the road along the path. The system issues a warning when, based on the current vehicle position and speed, a substantial level of braking would be needed to achieve a safely controllable speed in the curve ahead.
Working in tandem with the LDW and CSW systems is a situation awareness module (SAM), which serves as a central clearinghouse for analyzing data from radar, GPS, and sensors. By locating objects, such as parked vehicles or guard rails, relative to the vehicle's travel lane, the SAM can estimate lateral maneuvering room on either side of the vehicle. It sends this information to the LDW so it can dynamically adjust its lateral drift warning.
A unique aspect of the Visteon system, says Tim Tiernan, senior manager for Driver Awareness Systems, is that it uses different levels of alert, which he believes will lead to greater consumer acceptance. For example, if a car is moving out of a lane but there is no immediate threat of striking another vehicle or roadside object, the driver receives a vibration warning on either the left or right side of his seat, depending on the direction of drift. However, if the system detects that the car is in imminent danger of an accident, the driver hears a buzzing sound. There's also the option of posting cautionary or imminent visual alerts on an LCD in the car's instrument panel. In addition, the system adjusts to deliberate lane-hugging behavior and suppresses alerts, as in instances where a driver must avoid construction barrels on the side of a road.