I consider myself a good driver and a better parallel parker than most. Yet, still, one of my favorite technologies in modern cars' options list is semi-automatic parking assist. The smartest of today's cars can basically park themselves at the touch of a button.
In addition to just making life easier for lazy automotive journalists, parking assist systems make parking faster, more accurate and safer for everyone. However, these systems come at many different levels of sophistication and not all are created equally. To make your life easier, I've put together a guide to the different types of parking assistance tech and what we look for when deciding on our favorites.
Passive parking tech
At the most basic level, parking assist technology is any device or feature that boosts the convenience and safety of parking your car. This could include passive systems like the rear camera that boosts visibility when reversing or the guidance lines on the camera's feed that help to plot a course around obstructions.
Even more useful are proximity or parking-distance sensors that silently scan the area around the car and notify the driver when approaching an obstruction. These systems are especially useful because their audible alerts don't require the driver's full visual attention, you can keep looking around. However, the inclusion of a visual indicator on the dashboard (like those on BMW or Audi's parking distance sensors) further boosts the ease of squeezing into very tight spots.
Most proximity-detection systems use ultrasonic sensors that can double as rear cross-traffic alert systems that detect oncoming vehicles when reversing out of a parking spot or even for blind-spot monitoring on the highway. The most advanced of these features can even automatically apply the brakes when the sensors detect you're about to back into a wall or pedestrian or move into the path of a collision. I'm not a huge fan of auto-braking as false-positives can be jarring, but for inexperienced or inattentive drivers it's better to be safe and mildly annoyed than sorry.
What you want to look for is a system that gives you a lot of information about the area around your car without returning a lot of false positives. Generally, sonar is better than a camera-based system at avoiding hitting objects, especially at night or in the rain when visibility suffers, but cameras are better at avoiding curbs which ultrasonic sensors usually miss. If possible, get both: I like the BMW Park Distance Control's proximity heat map that works well with its 360-degree camera system. I also like Audi's Parking System Plus for its ability to customize the volume and tone of the audible distance alerts, which some may find annoying.
Active parking tech
Those same ultrasonic sensors are part of the requirement for the current cutting-edge of active parking technology: semi-autonomous parking or, as it's sometime known, parking with steering assist. As the name would indicate, these technologies feature computer-aided steering, so the other requirement would be an electric power steering system (EPS).
Here's how it most often works. When the active parking system is activated, ultrasonic sensors at the front and rear corners of the car activate to scan the roadside, detecting parked vehicles and the spaces between them and measuring those spaces.
By default, most systems scan the passenger side of the car where you're most likely to be parallel parking, but you can specify the direction of scanning by using the appropriate turn signal. You can also usually choose between parallel parking on the street and perpendicular parking in a parking lot on newer cars. The method differs from make to make, but most often it's toggled by tapping the parking assist button.
Once the car passes a space where the car will fit with a reasonable margin, it will alert you to first stop and shift into reverse. At this point, you should have a look and make sure that the spot is clear and legal. Current parking systems can't see driveways, fire hydrants, no parking signs or red-painted curbs, so if the space isn't legit keep on moving and the system will keep scanning.
If the space is legit, let go of the steering wheel and the car's computers will take over the electric power steering, turning the wheel for you and guiding the vehicle into the space. You, the human in the seat, retain control of the pedals and will need to ease off of the brakes in order for the car to move. The system may also call upon you to shift between drive and reverse gears, if corrections are needed for perfect parking.
At any point, you can grab the steering wheel to cancel the steering assistance and immediately regain control of the car, which is why it's important to actually let go of the wheel during auto-parking — if the car feels your hand on the wheel, it may (and probably will) cancel the assistance, leaving you to complete the maneuver yourself.
And since semi-auto parking can get cars into really tight spots — or perhaps the cars around you have changed position while you were away — the best systems will also feature an inverse feature called park-out assist. This feature will take control of the steering wheel while the driver shifts between forward and reverse, shuffling the car out of close quarters. Once the path is clear, the system will disable assist and leave you free to go.
I find that letting the computer do the parking is helpful in a variety of ways even for experienced drivers. For starters, it's often faster, more precise and certainly more convenient. The ability to automatically measure potential parking spaces alone makes semi-autonomous parking assist worth the cost of admission for larger vehicles and SUVs. It also totally removes the learning curve for unfamiliar vehicles and drivers, so you can lend your car to a family member and not have to worry about it returning with curbed wheels or dinged bumpers.
What you want to look for is simplicity of operation. Auto-parking systems have been around since 1999, but were complicated; it wasn't until 2009 that we started seeing systems with the holy grail of single-button operation. Look for one of those single button systems like Ford/Lincoln's Active Park Assist, FCA's ParkSense, Volkswagen's Park Assist or Toyota's Intelligent Park Assist. Many automakers also call their proximity sensors "park assist" as well, so make sure you're getting the one that steers. While you're at it, double check that your make and model also supports some sort of park-out assist to get you out of tight spots.
Remote parking tech
So far, the common thread of all parking tech is that a human actually needs to be in the driver's seat in order to park the car. However, that may not always be the case with the cutting edge of parking technology: remote parking.
Remote parking systems let drivers get out of the car and send their car to a parking space or summon it when it's time to drive. This could be as short a distance as a few feet to send the car into a tight space where the doors would be blocked for entering or exiting or as far as summoning the car from a remote garage on your property to pick you up at the front door. At this high level of tech, there are three tiers of functionality.
The first is basically remote control. You line the car up with the space, get out and hold a button on the key fob or smartphone app to send the car into the space. Take your finger off of the button and the car stops moving. On the surface, it's fairly simple.
Tesla's Autopilot Summon feature on the Model S and Model X are examples of this remote technology, as are BMW's Remote Parking feature on the latest 5 and 7 Series sedans. I should note that remote parking of any sort is not yet street legal in the US, so you'll be limited to using the technology on your own personal property — this is also why Mercedes-Benz doesn't offer the functionality on its North American models.
Tech tier two is what's called trained parking, which I've seen demonstrated by the Volkswagen Group and automotive supplier Continental. You must first "teach" the car a route — say, from your garage, along your driveway and to your doorstep — by manually driving it yourself. While being "trained," the car will be gathering information about the path via GPS and sensors located around its perimeter, be those cameras, ultrasonic sensors or both. With the path memorized, you can then exit the vehicle at either end of the path and send it away or call for it later via key fob or smartphone app. Each time the system runs the route, it reactivates the sensors to monitor for new obstructions, people or pets in its path and to learn more about its environment and should grow more accurate in its path-finding.
The final frontier, as it were, is truly autonomous parking. With a system like this, a driver would be able to just tell the car to go park and the car would handle automatically locating a spot and getting into it with no training or driver input necessary. You'd be able to drive your car to the airport at the beginning of your vacation, then send it home to park in your own garage, rather than paying pricey long-term lot rates. Likewise, a fully autonomous car would need to be able to find its way back to the driver, wherever they may be.
However, with fully-autonomous driving still some ways down the road, it'll be some time before we see a true self-parking car.