How Traffic Jam Assistance Systems Work

The boredom and monotony of driving in heavy traffic is about to get ... well, even more boring and monotonous. However, Volvo is betting that a lot of drivers will be relieved to have a reprieve from the stress of constant acceleration and braking, and may even find some other ways to make use of the time.

But can a car really help with traffic jams? It would be awesome, but alas, we aren't quite there yet. What this system does is help drivers cope with the frustrations and distractions of being stuck in a traffic jam. It's like cruise control, except it's designed specifically to work in heavy traffic instead of on an open road. It's limited to use at slow speeds -- in fact, it's intended for travel at 31 miles per hour (49.9 kilometers per hour) or less.

Like a lot of automotive innovations, this one came out of something else. As we've mentioned, it's a natural next-step from advanced cruise control technology. It's a follow-up of sorts to Volvo's Adaptive Cruise Control system, which uses a combination of a cameras and radar to maintain a safe, set distance behind the car in front (a direct but distinct evolution of the decades-old standard cruise control, which simply maintains a steady speed and relies on the driver's judgment to avoid obstacles), and Lane Keeping Aid, which uses a network of cameras and sensors to keep the car centered within its lane. Adaptive Cruise Control and Lane Keeping Aid are both fairly young, 2012 model year debuts, and it's clear Volvo is looking for ways to squeeze the most mileage out of the technology. In fact, sources indicate that Volvo probably had a more comprehensive suite of features in mind all along. The goal, company execs have said, is to make driving more relaxed [source: Volvo].

So, if you and your new Volvo find yourself in such a jam, you'll be ready. Your car will monitor the vehicle in front of you, and pace it to automatically maintain a steady following distance. It'll also steer to stay within the lane. If the car in front swerves to avoid an obstacle, your car can mimic the same swerve path by following the tire treads. Altogether, the traffic jam assistance system commandeers the engine, steering and brakes. So by pressing the button, the driver entrusts the car to make the most important judgment calls of heavy-traffic driving: steering, deciding when to accelerate, and decelerate and determining how much of a distance cushion to maintain around other vehicles and obstacles.

Similar systems are in development by Audi, VW, Cadillac, Mercedes and Ford, and all are projected to debut on selected models within the next two years. So far, it seems like most will operate in a comparable way, as they're also designed to allow completely hands-free operation in these low-speed scenarios. Owners of Mercedes equipped with traffic jam assistance systems have fewer options to pass the time, though -- these drivers have to maintain contact with the steering wheel for the system to work. If a driver pulls his or her hands off the wheel, the system won't engage. The Ford version of the system, which is similar to Volvo's, has a different plan in place. It uses audio warnings to alert the driver to take back control if the car determines there's too much nearby activity, such as frequent changes in adjacent lanes, lots of obstacles, or erratic and therefore unpredictable speeds of travel.

Traffic jam assistance represents a significant investment in development and research. Prototypes were tested with consumers for more than a year and evolved to meet customer demand. The traffic jam assistance system seems to be framed like a safety device that has potential to reduce fender-bender type crashes in heavy driving -- Volvo, after all, is known for coming up with the latest and greatest automotive safety solutions. Volvo freely admits, though, that development of the traffic jam assistance system was motivated by customer demand -- in other words, it's as much of a luxury feature as it is a safety one. It just happens to be comprised of safety-based technology. But there's more -- the name of the system, combined with its capabilities, seems to imply that it could perhaps reduce traffic jams by attacking the problem, rather than the symptoms. And if that's at all possible, Volvo is probably right on top of it.

Volvo, eager to determine if the traffic jam assistance system had more widespread potential, ran a few tests to see if it actually could alleviate traffic jams.

The SARTRE (Safe Road Trains for the Environment) project sounds like it was researching the safety of the super-long semitrailer trucks that are known as "road trains" in some areas (namely Australia). But in Volvo-speak, a road train is a pre-coordinated stream of cars that use advanced cruise control-type technologies to follow each other in a planned path of travel, with established safe following distances between each vehicle. A touch screen lets the driver input commands, such as joining or exiting the road train, or communicating with other vehicles in the road train, but beyond that, the driver of each individual car in the road train is largely relieved of the burden of driving.

The technology used in the SARTRE program, similar to the suite of tools that makes up traffic jam assist, was already in the cars used for the test -- it was composed of other safety features that have (in comparison) stood the test of time, like adaptive cruise control, blind spot monitoring and park assist. Since the cars' onboard diagnostics are so sensitive and precise, Volvo says that, at times, the road train traveled safely with less than 13 feet (3.9 meters) from bumper to bumper.

Volvo sees this technology as a plausible alternative to public transportation, providing a combination of an individual's own comfort with automated travel. It also offers moderate energy savings over regular driving, and takes up less space on the road than the same number of vehicles would occupy if each were driving independently. However, it's not as simple as just joining a line of cars that happens to be heading in the same direction. The road train must be scheduled and coordinated ahead of time, and led by a professional driver. There are too many questions that need to be answered, such as how well a road train can cope with an unforeseen road disaster. And, so far, all of Volvo's tests have been focused on potential for the European market -- whether or not this will fly in the United States is completely unknown.

There are reasons other than the home-court advantage that convinced Volvo to test in Europe. From an automaker's perspective, the United States' safety regulations are an absolute mess [source: Lavrinc]. In addition to the nationwide federal regulations, a handful of states have their own standards and restrictions that go above and beyond the national benchmark, which must be met for every car sold within that state. It's really difficult for automakers to develop new technology when these standards are constantly changing. Sometimes, it's nearly impossible for a new innovation to meet the most restrictive demands of a specific market -- even if it passes muster almost anywhere else. Europe, however, is a lot easier for a European carmaker to navigate. In other words, Volvo needed to ensure its tools worked as intended before custom-calibrating them became part of the plan.

If this seems like it's going somewhere else, it is. Volvo's ultimate objective is autonomous driving -- a car that can move with minimal input from the driver. The automaker says studies show that about half of all drivers would be comfortable in a self-driving car and part of the push for autonomous driving technology comes from an increase in potential distractions -- namely, texting [source: Volvo]. Widespread use of this technology could potentially cut down on accidents. Volvo is quick to point out that this shouldn't be a substitute for the driver's judgment -- any input from the driver's controls will override the automatic motions. (That's assuming, of course, that the driver is still awake.)

The progress that's been made in just the last few years eclipses the previous several decades, and at times, it seems like automakers are closer to their goals than they let on. But it's important to note that it's all happening gradually, at a controlled and deliberate pace. It helps everyone -- consumers and government safety regulators -- adjust to the changes slowly, so they don't become overwhelming or dangerous, which would threaten long-term acceptance and future development. If we went from something as simple as cruise control to fully-self-driving cars, without a steady flurry of new tech rollouts in between, people would probably be terrified and unwilling to give it a try. But by the time traffic jam assistance rolls out in 2014, consumers should be pretty well prepared.