With the full stability system engaged, the driver of the fully–loaded rear discharge mixer maintains control and avoids rolling his vehicle while making a sharp turn on the test track, as shown by the elevated rear safety axle.
On a cool fall morning, a group of reporters watched as a water truck sprayed a pylon-lined path on an asphalt lot at the Joliet Speedway near Chicago.
Fred Andersky, our host, had carefully replicated the test path engineers from the Transportation Research Center (TRC) in East Liberty, Ohio, had developed. We were about to witness a simulation of how a driver reacts in an emergency stop on a four-lane highway.
Andersky pointed to four cones positioned rectangularly on the right side of the lane. They represented a car or pickup that had unexpectedly stopped or significantly slowed down.
A 10-yard ready-mix truck then approached from our left at about 45 mph. The drum contained sand and water to simulate the effect of a fully loaded drum at legal load. The drum was rotating in the slow agitation position.
The driver continued at full speed until he reached 100 feet from the pylons marking the stopped car. Reacting as if he'd just noticed the parked vehicle, he quickly turned his truck to the left lane.
He avoided the simulated collision. But in doing so, the truck tipped so much to the left, a set of support wheels on an auxiliary axle contacted the asphalt and squealed. “If that safety axle wasn't there, the truck would have probably tipped over,” said Andersky.
The test driver continued along the path, passed us, and returned to the start line. “Now, watch what happens when the driver engages the full stability safety system,” said Andersky.
The driver approached the test area again at the same speed. At about the same spot, he began his emergency collision avoidance system. This time the truck made the turn, but instead of tipping, it reduced speed with a steady but jerky reaction. The auxiliary safety axles barely moved toward the ground. I'm convinced the chassis would have remained upright throughout the event and aftermath.
The test confirmed that Andersky and his team at Bendix Commercial Vehicle Systems have developed what could solve one of the industry's greatest transportation safety issues: roll-overs. Bendix engineers have labeled this safety technology electronic stability program/control (ESP/ESC)Systematic safety
A few minutes later, I was strapped in the passenger seat. Andersky took over as driver. After completing the test run, he stopped the truck to explain what I had experienced.
“We've designed a system that automates a vehicle's response to a driver's commands, practically before the driver realizes it's happening,” he said. A full-stability system utilizes additional sensors that signal a dangerous situation may be developing. In this case, this early input typically comes from the steer-angle sensor.