Almost every kind of vehicle has experienced a growth in size over the past decade. An "entry-level" car by a company such as BMW nowadays might be near the size and weight of a mid-size car ten years ago. As vehicles have gotten bigger, parking has become harder and harder.
The most obvious vehicle size increase has been in the pickup truck segment, where "small" trucks like the Dodge Dakota now look like giants beside their early predecessors. Full-size trucks have also been expanding, becoming heavier, wider and taller. Toyota too has participated in this growth trend. The Toyota Tundra was originally a mid-size pickup marketed to full-size buyers. Toyota realized a larger vehicle could fit more customers, and as a result, the 2007 Tundra was much bigger than earlier models in almost every dimension.
Size may have its benefits, but it has its downfalls as well. The biggest problem with bigger vehicles is that parking has become a lot harder. Sitting behind the wheel of a new Toyota Tundra, it might be hard to gauge just where the truck begins and ends. To make things easier, vehicle designers have introduced "parking assist" as an aid to drivers struggling with parking their new vehicles.
On most vehicles, "parking assist" is a system of sensors in the front and/or rear bumper that create an audible "beep" when your vehicle gets close to an obstacle. Depending on the system, the beeps will begin when you’re about 6 feet away, and then increase in frequency until you get about 6 inches away, when the beeps will become a continuous tone. This is a great feature - it can really help with parallel parking, as well as warning you if something small (i.e. a fence post, a mailbox, or even a small child) is near your vehicle. But how does it work?
The system is essentially a set
of "eyes", or sensors, mounted on the bumpers, and which emit highly focused sound waves at regular intervals. When the sound waves bump into an object, they will bounce back towards the sensor. Given that the speed of sound in air is fairly consistent, the computer can take the amount of time between the sound being emitted and when it returned to the sensor, and use this information to calculate the distance between the bumper and the object. The same principle is used by submarines in active sonar underwater. The main difference here is that sound travels much better in water than in air, so the submarine sensors have a better range.
While the system is effective when dealing with stationary objects like parked vehicles, posts and garage doors, the sensors are not quite sensitive enough to pick up smaller objects moving past the sensors. This means that small children, animals, or all-terrain vehicles might not generate a warning beep - or at least not a consistent warning beep. So, while parking assist - aka parking sonar - is definitely a useful tool, it is not a replacement for caution. Drivers must still do their best to ensure that there is no one behind or in front of their vehicle when parking.
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?
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