Intrusive, But Reassuring

In the quest to define tomorrow's car, safety often plays second fiddle to eye-popping telematics, fuel-sipping powertrains and weight-reducing materials.

Continental Teves AG is working to change that with its Active Passive Integrative Approach (APIA), which networks a swarm of existing safety technologies into a harmonious unit that promises to help tomorrow's drivers avoid accidents or soften the impact of a collision.

Continental recently demonstrated the technology in Frankfurt, Germany. Although most of its components already are in serial production as part of existing safety systems, APIA may not be adopted until the end of the decade. Even then, APIA may be limited for some time to top-shelf auto makers, more likely to go for new, more expensive safety technologies.

However, as the debate rages over how intrusive safety systems should be, APIA may face more scrutiny than the simple question of cost vs. benefit.

APIA encompasses 22 different in-vehicle controls and systems, in addition to an enclave of infrared sensors and radar detectors — most of which already do duty in vehicles equipped with electronic stability control (ESC) or adaptive cruise control (ACC).

The heart of APIA is a so-called “danger control” module that is integrated into the electronic brake system controller located directly behind the driver-side headlamp. The module simultaneously plays the role of sensor, processor and transmitter.

Think of APIA, designed primarily to prevent rear-end collisions, as the equivalent of the U.S. Dept. of Homeland Security's terror alert for your car. When the potential for danger is low, APIA's response is simple “gentle communication” with the driver, says APIA Project Manager Juergen Diebold.

As the potential for a collision escalates, “intensive communication” with the driver ensues, and eventually the danger control module takes over operation of the car.

The system calls on a variety of sensors to detect how quickly a leading vehicle is braking and determines the level of collision risk. Once that risk is calculated, the module signals the car's degree of response — from Level 1 to Level 5.

Continental employs small, upfront “enviro-sensors” slotted in discreet areas such as the headlamp assembly, Diebold says, in addition to side satellites, rollover sensors and a low-range pre-crash sensor.

Because most of APIA's response systems already are in vehicles equipped with ESC, the sensors make up a good percentage of APIA's minimal weight disadvantage, a Continental spokesman says. Even that disadvantage is limited, as many of the sensors already are on board as part of the ACC system.

Continental's ESC monitors the steering wheel and brake and accelerator pedals that provide driving behavior data to the danger control module. More aggressive drivers aren't necessarily higher-risk drivers when APIA is factored in, because they may be more alert to the system's crash-prevention communications techniques.

The first level of communication — triggered when a leading vehicle brakes just enough to create a safety risk — is subtle, but a bit disturbing to the first-timer. The subtlety comes in the form of an instrument-panel message warning the driver. More disturbing is the haptic feedback, or forced-feedback vibration, that is transmitted from the accelerator pedal to the foot, much like a vibrating video game controller. The system works with an otherwise normal pedal.

More sudden braking from the leading vehicle triggers Level 2 conditions. The accelerator pedal pushes back on the driver's foot, and pressure in the brake system is boosted, eliminating clearance between the pads and discs. The front seatbelts also are tightened slightly, using a pre-tensioner developed jointly with Takata Inc. It is capable of pulling passengers back into their seats with a maximum tug of 56 lbs. of force (250 N), but at Level 2 is pulling at only a fraction of that amount.

Also during Level 2, the sunroof and windows are closed automatically to prevent ejections and related injuries.

APIA goes into Level 3 mode when the gap with the leading car closes further and faster and the driver takes his foot off the accelerator. At this point, the car brakes on its own to decelerate at the maximum automatic rate allowable by law (0.3g) and further conditions the braking system for emergency procedures.

Seatbelts tighten enough to pull driver and front passenger into the safest possible position and keep them there, while the seat adjusts itself into the optimal position in preparation for a collision.

Level 4 is signaled when the leading vehicle goes into a full emergency stop. Here APIA really takes over. The seatbelts pin occupants with their full force, more than double what is traditionally employed. If a driver isn't applying enough brake pressure, the system acts on information supplied by the enviro-sensors and builds up as much pressure, or braking torque, as needed to bring the car to a stop.

In Level 5, APIA controls airbag deployment force and timing to best protect the occupants based on how a collision will impact the cockpit. The bags rely on the car's precise pre-crash sensors, which detect activity in a relatively short 32-ft. (10-m) field and sensors that determine occupant position and size.

Continental's smart airbag system, along with the seatbelts, make up the passive contribution to APIA that could lessen injuries and deaths significantly, the supplier says.

While APIA appears to work in actual crash scenarios demonstrated for journalists, Diebold says Continental still is proving out the technology. The system's next generation promises to feature steering-wheel feedback much like the pedal haptics employed during APIA's Level 1 deployment. In addition, engineers tell Ward's, Continental still is trying to verify that APIA's braking system's heightened intervention will work in all potential situations.

Eventually, if systems like APIA gain acceptance, Diebold says the next step will be a “seeing car of the future,” featuring onboard intelligence, data interchange with other vehicles and telematics information that will lessen the reliance on passive systems by totally avoiding high-risk situations well before the car approaches them.