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Intelligent parking assist systems

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Intelligent Parking Assist Systems (IPAS) are available commercially with several brands of passenger cars and SUVs in the United States. This technology has been touted to have several benefits related to parallel parking. These include : [1]

  • Removing the difficulty and stress associated with parallel parking
  • Allowing cars to fit into smaller parking spaces
  • Reducing the amount of time and traffic disruption required with parallel parking
  • Preventing minor dents and scratches by less-skilled drivers



This technology was first introduced by Toyota in 2003 when they included the option on their Prius hybrid model available in Japan. [2] In 2006, this self-parking feature was first introduced to the United States in the Lexus LS by utilizing the system developed by Toyota. [3]

The use of this technology has continued to increase over the years. The following list of vehicles offer IPAS as an option in at least some of their models: Toyota (Prius), Ford (Escape, Explorer, Flex, and Focus), Lexus (LS 460 and LS 600h), and Lincoln (MKS and MKT). [4]

How it works

Self-parking cars are not completely autonomous, but they do make parallel parking much easier. The driver is required to regulate the vehicle’s speed through the brake pedal while the on-board computer system takes control of the steering wheel. [1] Currently, there are essentially two different systems used for parking assistance – one developed by Toyota and the other developed by Ford. Some would argue that the Toyota system is more complicated due to the driver being required to complete more actions. For instance, the driver must target a parking spot via the back-up camera and touchscreen prior to the system taking control (as seen below). [4]

Screenshot of Toyota system being used.
Screenshot of Toyota system being used.

See "External Links" section below for more information comparing the two systems.


The different available systems have unique ways of sensing the objects around the car. The most common options are sensors or cameras. Sensors distributed around the bumpers act as both transmitters and receivers. They transmit signals, which bounce off objects and reflect back. The on-board computer uses the time delay to calculate the location and distance of these objects. Others use cameras mounted onto the bumpers to detect objects. Regardless of the sensing hardware, the car is able to detect other objects and distances, and then steer into the space. [1]


The car moves forward into position beside the front car, and a signal lets the driver know when to stop. The driver then shifts into reverse and lets the computer take over the steering wheel. The driver manages the vehicle’s speed through the use of the brake pedal until another signal lets the driver know when to stop the car and shift into drive. Again, the driver uses the brake pedal to pull the car forward as the computer maneuvers the vehicle into the space. A final signal tells the driver when parking is complete. [1]


  1. 1.0 1.1 1.2 1.3 [1], How Stuff Works.
  2. [2], Self-parking car.
  3. [3], Advance Parking Guidance System.
  4. 4.0 4.1 [4], Self parking systems comparison.

External Links

Active Park Assist A comparison of the Ford system vs. Toyota system (Created by Ford).

Self-Parking Systems Comparison Test A non-biased comparison between Ford and Toyota (with video).

Intelligent Parking Assist for Toyota Prius A review of the Toyota system (including video).