Parking sensors are becoming more commonly fitted to vehicles, but how do they work? Can a car's design affect installation and will they look factory fitted?
How Do Parking Sensors Work?
As the car reverses into space and moves closer to objects, an audible buzzer beeps more frequently.
This is usually achieved by four ultrasonic parking sensors fitted into the bumper of the car. They send out an ultrasonic wave, and if this hits an object, it bounces back to the same sensor. Information received is then relayed to the brain, allowing it to make the buzzer sounds.
Will Bumper Design Dictate Installation?
For most vehicles the shape of the car will determine where sensors are fitted. This is due to wide differences in design, between manufacturers and models of vehicles.
For cars with a center panel and separate corner bumper pieces that curve around the car, two low and two higher sensors are often necessary. If a vehicle has a metal panel behind the bumper, this usually means holes must rise above the obstruction, also avoiding interference issues.
What are the Differences Between Factory and Retrofit Fit?
Factory fitted parking sensors are the ones fitted to a car at the time of manufacture. Retrofit, often called 'After-market', are the ones fitted at some time after the vehicle was produced.
Factory fitted sensors have a certain look, devised by the car designer, which is difficult to recreate in aftermarket sensors. Retrofit devices are made for all cars from all manufacturers, and clearly have their own distinct look.
It could be argued that some of the latest aftermarket designs are better due to their small, discreet shape. They are also constantly being redesigned for better looks or usage, and not devised and forgotten like factory ones.
What Size?
Sensor heads are getting smaller. Small is definitely less intrusive although they may have limited color options, for example only available in black or silver.
Usually it is best to go for the smallest sensor heads possible, as once a hole is drilled it can not be made smaller.
Do I Need Front Parking Sensors?
Factory fitted front parking sensors are integrated into the vehicle's ECU. They will automatically switch on, and instinctively sense if you begin a parking manoeuvre. Aftermarket versions, with the same functionality, can be expensive and are not available for all vehicle models.
A realistic option for front sensors is to use a switch. This avoids the system becoming active when moving slowly, for example in a traffic jam, but means the driver switches on the system before beginning to park.
It is also worth knowing that generally drivers can see the front of their cars. This means that while rear parking sensors are a significant help when parking, the gains from front ones are limited.
