Acura is the third automaker to offer collision preparation technology, featuring it on the top-of-the-line 2006 RL sedan. Dubbed the Collision Mitigation Braking System (CMBS), it’s teamed with a millimeter-wave radar unit mounted behind the Acura symbol in the grille, which monitors the distance between the RL and objects in front of the car, as well as closing rates. CMBS then determines if a frontal collision is likely to occur. The system scans up to 330 feet in front of the car, and works at speeds above 10 mph.

CMBS operates in three stages. In the first two stages, which are non-critical situations where the driver can still avoid a collision, the system uses audible and visual alerts to inform the driver that the RL is closing on an object more rapidly than is safe. In stage one, the RL beeps and flashes a “brake” warning in the gauge display. In stage two, the RL repeats the audible and visual warnings, while also pre-tensioning the driver’s seatbelt and automatically applying light braking to reduce speed. In stage three, things get more serious. CMBS continues audible and visual warnings, but now pre-tensions the front passenger’s seatbelt and automatically applies harder braking to scrub as much speed as possible before impact. Note, however, that Acura warns the system is not designed to bring the RL to a halt. For that, the driver must step on the brakes. CMBS can pass through all three stages quickly, or can transition slowly, depending on the RL’s closing rate with a moving or stationary object.

We learned first-hand how effective CMBS is during a demonstration drive designed to fool the system into thinking that a collision was about to occur. By driving parallel to an Acura MDX with an object hanging off the side of the SUV, we were able to engage all three stages of CMBS. Though the audible alert’s beep-beep-beep is somewhat intrusive, the system works subtly and smoothly. Even in stage three, when the seatbelts tighten up and the braking system is engaged, it works with an unbelievable degree of refinement. But the best part of CMBS is that it applies the brakes automatically, so that if the driver has suffered a medical problem and can no longer operate the vehicle the RL will slow down as much as possible before impact. Lexus and Mercedes systems don’t make a move without driver intervention.

CMBS is currently offered only on the RL with the Technology Package, bundled with an active cruise control system and Michelin PAX run-flat tires, which commands an estimated premium of $4,000 over the standard model. Acura plans to equip about 10 percent of all 2006 RLs with this package.