Automotive technology is constantly evolving, resulting in vehicles that are faster, stronger, more comfortable and more efficient. Automakers race to bring the newest technology to market, careful not to find themselves so far out on the cutting edge that the technology proves troublesome, or even worse, dangerous for drivers. Certainly, high-tech advances geared toward safety must be not only effective but reliable. Newly introduced in the last few years, collision avoidance systems have proven to be both reliable and effective.
After the success of seatbelts and airbags, automakers began focusing on systems aimed at preventing accidents. Unlike passive safety systems which protect occupants in the event of an accident, active safety systems are intended to help prevent accidents all together. Anti-lock brakes are an excellent example of an active system. The ability to control the vehicle while applying maximum braking force allows drivers to simultaneously slow the vehicle and steer away from harm.
Collision avoidance systems, or crash avoidance systems, are active safety systems that can help drivers prevent accidents by detecting and warning drivers of potentially dangerous situations, and even intervene should the driver fail to act on the warning. New research shows that these sophisticated systems are highly effective, and many manufacturers are rolling out crash avoidance systems in their newest vehicles.
We examine and compare the systems of five automakers, presenting how each system detects a possible collision, how it alerts the driver, and what evasive action the system takes to avoid a crash. Collision avoidance can include responses to a range of potentially dangerous situations. This article specifically focuses on forward collision warning designed to prevent rear-end accidents.
Volvo’s Collision Warning with Full Auto Brake (CWFAB) was the subject of a study by the Highway Loss Data Institute, a non-profit that publishes insurance loss statistics. The study found that Volvo XC60s equipped with the system showed a 27% drop in claims filed due to rear-end accidents, compared with the same model and similar SUVs with no collision avoidance system. Volvo is keen to point out that rear-end collisions account for a third of all reported collisions. In a staggering half of those, the driver never brakes at all.
The Swedish automaker’s CWFAB differs from other systems in that it can automatically bring the vehicle to a complete stop. Many other systems will only slow the vehicle as they alert the driver of danger. The system, which includes adaptive cruise control, relies on radar and a camera to detect stationary and moving vehicles and alerts the driver to potential danger through an audible indicator and a flashing light in the heads-up display visible in the windshield. Volvo offers the system on S60, V60, XC60, XC70, V70, and S80 models.
GMC just introduced the first camera-only system on the 2012 Terrain. Most collision avoidance systems include an adaptive cruise control feature. While GMC’s lacks adaptive cruise, it does include a lane departure warning, alerting the driver of an unsignalled lane change. Another advantage to the Terrain’s system is price. The system adds just $295 to the bottom line.
The camera uses four separate exposures for each image, allowing effective detection day or night. Should the system recognize potential danger, an audible warning and a high-mounted visual display alert the driver. Simultaneously, the brakes are pre-charged, readying the vehicle for the shortest possible emergency stop.
Mercedes-Benz offers the Distronic Plus adaptive cruise control system, which includes the company’s Pre-Safe collision avoidance program, on their S, CL, CLS, M and E-Class automobiles. Mercedes has long been at the forefront of vehicle safety, having pioneered such advancements as ABS and stability control.
Like Volvo’s offering, Pre-Safe is capable of applying full-power braking to mitigate damage from a collision. Mercedes employs radar detection and includes a lane-departure component. In addition to audible and visual warnings in case of a potential forward collision, Pre-Safe notifies the driver of lane departure with vibrations in the steering wheel that simulate roadside rumble strips.
Acura calls its radar-based crash avoidance technology Collision Mitigation Braking System (CMBS). Available on the RL, MDX and ZDX, Acura’s system includes adaptive cruise control but lacks a lane departure feature. As in the Mercedes, tactile indications join audible and visual signals to let the driver know of potential danger. An advanced seatbelt tensioning system gives several quick tugs on the shoulder belt, enough to alert even the most distracted driver of an impending collision. CMBS simultaneously initiates braking if closing speed suggests the driver is not responding quickly enough. In fact, should the vehicle detect a very high closing speed, CMBS may fully intervene, tensioning belts, braking and preparing safety systems for collision, without ever indicating the hazard to the driver.
Lexus offers its Pre-Collision System on all of its sedans and SUVs, except for IS. Including an adaptive cruise control feature, PCS alerts the driver through audible and tactile indications. While preparing for emergency braking, PCS also stiffens the suspension when possible (on models with Adaptive Variable Air Suspension) to allow the vehicle to better respond to emergency maneuvers.
While the PCS relies on radar for detection, Lexus also offers its Advanced Pre-Collision System which uses stereo cameras to detect smaller, non-metallic obstacles like pedestrians. This cutting edge technology even includes a system that monitors the driver to ensure alertness. Should the steering wheel-mounted camera detect that the driver has looked away from the road for too long, audible warnings and flashing lights attempt to bring his or her attention back to the road ahead.
Safety is of paramount importance to many car buyers. A study by Consumer Reports asked buyers about the top three factors they consider when buying a new vehicle. More respondents gave safety as a top factor than any other attribute, even beating quality and value. While some safety advancements have shown negligible benefit in the real world, collision avoidance systems show significant promise in reducing the number of accidents and mitigating the effects of those that still occur.
The systems of the five automakers outlined here represent just a fraction of the new models with available collision avoidance technology. Like many high-tech features, crash avoidance systems were first introduced on top-tier models. But the best technologies always trickle down to more common and affordable models. Expect to see these systems on a growing number of makes and models while the benefits they offer result in fewer dangerous and costly accidents.