Following the success of parking sensors, supplied as part of the original spec with new cars, a number of companies are offering diy parking sensor kits from as little as £49.99. These kits use emit a cone of sound behind the vehicle which
bounces off obstables behind and returns to the sensor. It is the time taken for these
sound waves to bounce and return off obstructions behind the car that are used to
calculate the distance to the obstacle behind.
A number of options are available. Some are flush mounted and others use self adhesive backing. Some parking sensors use audible beeps, others have visual displays.
A new development being worked on by a number of manufacturers such as VW, is cars with automatic parking capability. the majority of the systems being developed, still require the driver to use the accelerator and brake, whilst operating the steering automatically.