System helps drivers stick to the straight and narrow

The Nissan Altima veers to the right, crossing the dashed line on the road, and a prototype warning system in the car doesn't like it. It delivers a cautionary warning by causing the driver's seat to vibrate on the right side and a yellow arrow to appear on a screen next to the speedometer.

Later the car begins to cross a solid line. The car goes into "imminent warning" mode; the arrow on the screen turns red, and a noise, intended to sound like the car is traveling over rumble strip, is heard from the right side stereo speaker.

Abovet, the Driver-Vehicle Interface display on the dashboard of one of the test vehicles indicates with an arrow that the car is drifting to the right. Below, Joel Devonshire, research associate with UMTRI, points out some of the features of the Data Acquisition System in the trunk. From the information gathered here, Devonshire says, "We can see what the driver was doing that caused the warning, what their reaction was after the warning happened and other information." (Photos by Paul Jaronski, U-M Photo Services)

The car is one of 11 being developed and tested through a joint effort of the U-M Transportation Research Institute (UMTRI), Visteon Corp. and Assistware Technology. The U.S. Department of Transportation is sponsoring the field operational test of the Road Departure Crash Warning system. UMTRI is the prime contractor to the Department of Transportation and is responsible for designing and conducting the field experiment.

The warnings relate to "lateral drift"—when a vehicle veers from the lane and risks collision with another vehicle or fixed object, or leaves the road surface and risks a rollover—and curve overspeed—when a vehicle is traveling too quickly to navigate an upcoming curve successfully. The goal of the project is to help identify warning systems that can prevent a large portion of single-vehicle road departures. These account for approximately 20 percent of all police-reported accidents but represent 40 percent of all traffic fatalities—or more than 15,000 people killed in the United States per year.

"This is a major slice of the traffic fatality problem," says Jim Sayer, assistant research scientist at UMTRI, a co-principal investigator helping to conduct the study along with research professor and project director Robert Ervin and co-principal investigator David LeBlanc, assistant research scientist.

Evaluation of the vehicles started last month. During a 10-month period, 78 participants will drive the Altimas for one month each and give their opinions at the end of their experience. Data are collected along the way about vehicle speed, lane position and the driver's reaction to the warnings. A comment button on the dashboard also allows drivers to record comments and suggestions as they drive.

The lateral drift warning uses a yellow arrow and seat vibration when the vehicle crosses a dashed line without using the turn signal. If the car is crossing a solid line without signaling or approaching an object along the side of the road, a red arrow flashes on the screen and a beeping sound is presented to the driver.

Unlike departure warnings that already are sold with some vehicles, the system looks not only for the crossing of lines but also for objects the car might strike if it were to leave its lane or the roadway, such as a parked car, bridge embankment or guardrail. The system processes data from a video camera to measure lane position and radar units detect objects that are potential threats.

"This is designed in part to address the problem of drowsy drivers and driver inattention," says Joel Devonshire, research associate with UMTRI, who assists the people chosen to test-drive the cars. "It's designed for those times when you're not paying attention and you'd definitely want to be warned."

The curve speed warning uses arrows on the screen and seat vibrations similar to those used in the lateral drift warning. In addition, a voice says "Curve, curve" to signal a severe warning. A global positioning system antenna and an onboard map database determine the vehicle's position, future path and geometry of the road along that path. The system also offers earlier alerts in rainy or cold-weather conditions, when there may be less traction available.

Researchers are looking into solutions for some issues with the system, such as the possibility that the lateral drift warning won't activate if the camera can't detect lines in the road during a snowstorm.

The system could be especially helpful to drivers of heavy trucks, people who regularly drive at night or people who are traveling in unfamiliar territory, Sayer says. He and others have high hopes for the system and think it could be commercially available in vehicles within a few years.

"The federal government wouldn't be investing the money and UMTRI wouldn't undertake the research if we didn't think there were near-term possibilities for this system," Sayer says.