The National Transportation Safety Board truck safety hearing continued in Nashville yesterday with a closer look at several existing and prototype truck safety technologies, including collision warning systems, new brake technology, and rollover warning and prevention.
Electronic braking systems, also called "brake by wire," use an electronic treadle to activate the brakes for faster response time. Although these systems are getting good response in Europe, where they are paired with disc brakes for up to 40% better stopping distance, there are barriers to their acceptance in the United States. Current federal brake requirements mean that any EBS system must be put in on top of the existing dual pneumatic braking system. This keeps the cost higher than fleets are willing to pay.
Although the stopping distance with EBS alone is only 2% to 5% better, the system is important in its potential use as a platform for other new safety technologies. For instance, Eaton testified about new technology under development called the Electronic Stability Program or Vehicle Dynamic Control System. It works with electronic braking systems. In the case of loss of control that could lead to a rollover, the system can brake each wheel independently, without any action by the driver, to bring the vehicle back under control.
Scott Stevens with Oak Ridge National Laboratories said his consortium is taking a different approach to rollovers. "The point of our project is to avoid the drama," he said after the board viewed a dramatic demonstration of Eaton's system. The rollover warning system, to be tested in three U.S. Xpress trucks over the next year, uses information from trailer sensors and the engine ECU to tell drivers if an upcoming curve offers rollover danger.
U.S. Xpress' Max Fuller also testified about the company's experience with Eaton VORAD collision warning systems. All three trucks on display at the hearing were equipped with the units. Eaton's newest incarnation of the product includes a smart cruise feature that will automatically slow the truck if the radar warning system detects the truck is closing on an object ahead.
Chris Royan with Eaton VORAD testified that studies show a full extra second of warning can prevent up to 90% of rear collision accidents. Customers have reported reductions in rear-end and lane-change accidents from 35% to 100%. The system also offers an accident reconstruction feature that the board found interesting.
In the future, Royan predicts that the systems will become smaller and integrated into OEM driver displays. Backup sensors and side trailer sensors could be added. Smart braking could be used to slow the truck; currently the smart cruise uses defueling and the engine brake to do the job. And the information generated by the system could be sent through Qualcomm to fleet headquarters instead of requiring downloading with a diagnostic tool.
The NTSB hearing continues today with witness panels on technology to improve vehicle inspections, data recorders, and technology developments by vehicle manufacturers.