The full scoop on autonomous cruise control

The typical Canadian new car buyer will be returning to a showroom for the first time in about six or seven years. In an industry where changing demographics, shifting global economies and ever-tightening fuel economy regulations are forcing the automobile to change faster than ever before, many new car buyers may not be aware of what’s available with the new 2014 models in regards to body styles, features or technologies.

Take for instance the recent introduction of autonomous cruise control technologies, a high-tech safety feature once only thought to exist in science fiction.

Autonomous cruise control (ACC) is an automatic system that adjusts your vehicle’s speed to keep a safe, pre-determined distance behind vehicles travelling ahead of it in the same direction. ACC systems allow a vehicle to slow when approaching another vehicle ahead and accelerate again to the preset speed when traffic allows. Experts say the effectiveness of ACC is in its positive impact on driver safety and its potential to reduce traffic congestion by adjusting the distance between vehicles according to the conditions. The technology is also generally seen as a key component of future generations of intelligent cars that will “link” together to create a true, autonomous driving environment.

That may be the future, but today’s ACC systems already offer a lot of value.

ACC systems are either laser or radar-based. Laser-based ACC systems cannot locate and track other vehicles in bad weather conditions. They also have a hard time tracking really dirty cars that are less reflective. (You’ll know if a car has a laser-based ACC system, as it uses a large box found low at the front of the car offset to one side so the laser can have a direct line of sight.) Conversely, radar-based ACC sensors can be hidden behind plastic bodywork or grilles. (Those with keen eyes will still be able to notice if a vehicle has radar-based ACC, as the units are usually covered in a black plastic, behind the grille slates.)

2014 Mercedes-Benz S-Class.

The 2014 Mercedes-Benz S-Class has a sophisticated autonomous cruise control function..
Handout, Mercedes-Benz

Today, each automaker brands their respective ACC systems differently (e.g. Mercedes-Benz calls its system “Distronic Plus, whereas BMW brands it “Active Cruise Control with Stop & GO”). The first known production ACC system came from Japan’s Mitsubishi, which made its laser-based ACC — dubbed Preview Distance Control — available on its topline Diamante luxury sedan in 1995. Unlike today’s systems, though, Preview Distance Control did not employ the brakes, and only dialed back the throttle and downshifted the car’s automatic transmission. In North America, the first ACC technology was made available on the 2000 Lexus LS 430 luxury sedans, marketed as Dynamic Laser Cruise Control.

Since ACC systems can apply a vehicle’s brakes far more quickly than a driver can react, the biggest benefit to buying a new vehicle with ACC is avoiding rear-end collisions — the most common type of car crash, according to the U.S. National Highway Traffic Safety Administration. Of the nearly 6.2 million police-reported collisions in 2005 in the U.S., 29.6 % were rear-end collisions. But ACC can also be an aid in congested, stop-and-go traffic.

Most of today’s ACC systems can bring a vehicle to a complete stop and then accelerate it again when the vehicle ahead starts to move as well. And the most up-to-date systems provide visual and/or audible warnings to the driver and can tighten seat belts and prepare the air bags for a possible collision. This prevents drivers from slamming on their brakes, and potentially creating the same situation to happen to vehicles following them, thus reducing potential accidents and traffic congestion overall.

Of course, combining ACC with other dynamic safety technologies only makes for even safer driving experience.

Take for instance Mazda’s i-Activsense, an overall safety package that brings together its radar-based ACC with a host of other technologies (get a pen out!), that includes: adaptive front lighting (supports safe driving at night by turning the headlights based on the degree of steering input and vehicle speed to maximize illumination and visibility at curves and intersections); high-beam control (detects oncoming traffic and vehicles in front and automatically switches headlights between high and low beam, improving visibility at night and aiding hazard avoidance); smart brake support (automatically applies the brakes when a risk of frontal collision is detected while driving at speeds of 15 kilometres per hour or more); smart city brake support (automatically stops or reduces the speed of the car when there is a risk of collision with the vehicle in front while travelling at speeds of between four and 30 km/h); acceleration control for automatic transmission (avoids sudden acceleration by curbing engine power output and alerts the driver if the accelerator pedal is pressed excessively while there is an obstacle in front of the car); rear vehicle monitoring (detects cars in the blind spot on either side or approaching from behind and alerts the driver); lane departure warning (detects lane markings on the road surface and warns drivers of imminent unintentional lane departures); and forward obstruction arming (detects vehicles in front and alerts the driver to an approaching risk of collision early enough for the driver to brake or take evasive action.)

In the past, ACC systems have been limited to high-end luxury cars. But as the cost of the technology drops and the systems have been standardized throughout the industry, ACC has become available on more affordable and smaller vehicles, like the Buick Verano, Mazda3 and Nissan Rogue, to name only a few.

About John LeBlanc