Vehicle Parking Assist Systems Explained

Vehicles of virtually every type and make have been steadily growing over the past ten years. “Entry level” cars by companies like BMW are almost the same size nowadays as a mid-size car from a decade ago. One of the consequences of vehicle sizes expanding is that parking now is harder than ever.

The vehicle growth spurt is most visible in the pickup truck segment, where even such “small” trucks as the Dodge Dakota are now so big that they dwarf earlier models. Full-size trucks too have grown, getting heavier, wider and taller. Toyota vehicles have followed this market trend. When it was first introduced, the Toyota Tundra was a mid-size pickup aimed at the full-size crowd. But when Toyota realized they could fit more buyers in a larger vehicle, the 2007 Tundra redesign ballooned the truck in almost every dimension.

While size does matter, all of that increased mass is nowhere near as easy to park as it used to be. For instance, when you ride in a new Toyota Tundra, you’ll probably find it difficult to tell exactly where the truck begins and ends. Vehicle designers, in an effort to make our lives easier, have come up with something called “parking assist” to help overcome this issue.

“Parking assist” is, on most vehicles, a system of sensors mounted on one or both sets of bumpers which beeps as the vehicle approaches an object. The beeps usually begin from about 6 feet away from an obstacle, and increase in frequency as you approach, becoming a continuous tone at about 6 inches from the obstacle. Beeping frequency and onset vary between different systems. The parking assist is a great tool for parallel parking, and can also serve as a warning if a small object such as a fence post or child is near your vehicle. But how does it work?

The system works using a set of “eyes”, or special sensors, mounted in the vehicle’s bumpers. The sensors regularly transmit highly focused sound waves from the bumpers, which are reflected back towards the sensor whenever they hit a solid object. Since sound travels at a fairly constant speed through air, a computer can calculate the distance between the bumper and object based on the amount of time it takes for the signal to return to the bumper. Submarines using active sonar underwater employ the same basic principle, although water transmits sound better than air, which results in better range for the submarine sensors.

The system is effective with detecting stationary objects such as other vehicles, posts and garage doors, but is not sensitive enough to reliably detect smaller moving objects, such as animals, all-terrain vehicles, or children. These small objects might not generate a consistent warning beep, or even any warning at all. Thus, although parking assist systems, also called parking sonar, may be a great tool for parking, they cannot replace driver caution. It’s still up to drivers to check that there is no one in the way of their vehicle as they park.

The next generation of parking assist systems has begun to appear in high-end luxury cars, and it’s really quite amazing. Rather than using just sound sensors - which are somewhat inaccurate - the system uses a video camera and a complex computer program in conjunction with the sound sensors. Instead of just warning the driver when they get close, this next generation of parking assist actually steers and parks your car for you. This is really helpful with parallel parking - just so long as you’re willing to let your car work the steering, gas, and brake. What will they think of next?