DEARBORN, MICHIGAN - How does Ford distinguish its new Curve Control safety feature from AdvanceTrac with Roll Stability Control? Curve Control, which debuts late this year on the new, unibody 2011 Ford Explorer, uses the Roll Stability Control and accelerometer to determine whether a driver is taking a curve -- say, an off-ramp -- too fast. While stability control can brake an inside wheel or two to control understeer, Curve Control uses torque reduction and/or brakes to cut the Explorer's speed by up to 10 mph in 1 second as the Explorer is entering the curve, to save the driver from understeering off the road.
Ford let us ride in the new Explorer, one that was heavily disguised even on the automaker's private test track, to show off the new technology. With Curve Control off, the driver understeered over cones set to replicate a typical freeway offramp. On the second run, with the system on, the driver again gave the wheel about a half-turn to the left, the Explorer yawing. As soon as he turned the wheel, the system slowed him down as advertised, and the Explorer made it inside the cones at a safe, if boring, speed.
"It needs at least 0.65g to activate," the driver tells us. The system is designed to work on dry or wet pavement, but so far, not snow. Ford is working on the low mu setting for the system. The system deactivates when the Explorer's terrain control is set for mud or sand conditions.
Curve Control required some new hardware, but it also was important to upgrade AdvanceTrac's software, says Paul Mascarenas, engineering vice president for global product development. Ford plans to extend the technology to 90 percent of its trucks, sport/utilities, and crossovers by 2015, including the Escape, Edge, Flex, F-150, Transit Connect and E-Series vans. New Ford and Lincoln cars will eventually get the system, too.
Ford says it's introducing Curve Control on the '11 Explorer because the technology, which its engineers have worked on for the last 18 months, comes along at the right time. Still, the nameplate "Explorer," which moves from a body-on-frame SUV to, essentially, the replacement for the Freestyle/Taurus X, conjures up images of rollover accidents involving underinflated Firestone tires.
While it would have been cheaper simply to rename the model, Ford says Explorer, its second-bestseller after the F-150 through the '90s and early '00s until the rollover problem emerged, remains a popular model in raising consideration for the Ford brand.
Ford quoted accident statistics that show about 50,000 serious accidents in the U.S. per year occur when drivers enter a tight curve, mostly an offramp or onramp, too fast. Ford didn't immediately have figures breaking out the percentage of vehicles among those 50,000 that are trucks, crossovers, or other high center-of-gravity vehicles.
Curve Control works whether the driver lifts and/or brakes, or panics and keeps his/her foot on the throttle pedal, our test driver says. The 10 mph-in-one-second speed reduction can be any combination of engine braking and torque reduction, and Curve Control will use "four-wheel smart braking," if necessary, using "different, precise levels of braking to each wheel," Mascarenas says. Yes, the driver can turn it off, whether or not he/she is driving in mud and snow.