A NEW technology intended to avert occurrences of heavy-duty truck rollover was demonstrated July 8 by Freightliner LLC and Praxair Inc at the National Intelligent Vehicle Initiative Meeting in Washington DC. Called Roll Advisor & Control, the system alerts truck drivers to potentially dangerous driving behaviors and/or automatically slows the vehicle to help prevent rollover. Roll Advisor & Control was developed by Freightliner in conjunction with MeritorWABCO.
Freightliner and Praxair are evaluating Roll Advisor & Control as part of the Department of Transportation's Intelligent Vehicle Initiative (IVI). IVI aims to accelerate the development and commercialization of intelligent vehicle systems that improve traffic safety.
"Freightliner is committed to developing technologies that actively prevent vehicle accidents and is pleased to demonstrate a safety feature that specifically addresses the problem of truck rollover," said Gary Rossow, Freightliner director of government technical affairs. "Safety is the top priority of Praxair in all our operations, including in our fleet of heavy-duty trucks," said Tom Rule, Praxair Internal Distribution Consultant. "We are keenly interested in exploring new truck technologies to give our highly skilled, extensively trained drivers every advantage to operate safely."
According to DOT, rollover crashes account for about one-half of the annual heavy-duty truck driver fatalities. In 1998, there were 728 fatalities in large trucks. Rollover crashes also result in extensive property damage and may shut down major roadways during rescue and clean-up operations.
Roll Advisor & Control has two integrated components: Roll Stability Advisor and Roll Stability Control. Both utilize sensors integrated into the truck's antilock braking system. By tracking the truck's lateral acceleration and wheel speed, the system detects the potential for rollover.
Roll Stability Advisor is a training aid designed to notify the driver that he or she has operated the vehicle in near rollover conditions. Warnings are communicated via the Freightliner Driver Message Center, a display located in the dash directly in front of the driver.
Roll Stability Advisor communicates messages with increased urgency as the potential for rollover increases. The first level of alert is a message that reads "Risky Maneuver Detected."
The second level of alert involves an alternating message that reads "Rollover Risk Detected" with a recommended slower speed. This message is displayed until the driver pushes a button to acknowledge it.
The third level of alert involves an alternating message that flashes "High Risk of Rollover Detected" with a recommended slower speed. At this highest level, a tone also sounds to signal that a high rollover risk event has occurred.
Instances of Roll Stability Advisor warnings can be recorded by an onboard computer. Fleet managers can download information on rollover warnings.
The Roll Stability Control function takes rollover prevention to the next level by automatically slowing the vehicle. When sensor data indicate that a rollover is imminent, Roll Stability Control sends a signal to the engine's electronic control unit to reduce power and apply the engine brake. When the vehicle becomes stable, power is restored and the engine brake is turned off.
Rossow said that Roll Stability Control shows the benefits of integrated, electronically controlled truck components. In this system, the antilock braking system and engine work together to dynamically control the vehicle.
Roll Advisor & Control is being tested in six of Praxair's trucks. The vehicles are Freightliner Century S/T Class 8 daycab tractors operating out of Praxair's LaPorte, Indiana, plant. All of the tractors in the evaluation are pulling liquefied nitrogen trailers. Freightliner plans to make Roll Advisor & Control standard equipment on its top-of-the-line Century Class S/T (Safety/Technology) truck at the end of the year and optional for other Freightliner Class 8 trucks.