Subaru is one of the first manufacturers offering advanced driver assistance technologies on a bread-and-butter mid-size vehicle. The privilege isn't cheap; you'll have to shell out an extra $3,940. Really though, you're paying $1,295 for this functionality specifically, since it's only available in a combination package that includes the moonroof and navigation system.
The company's Eyesight system employs two cameras mounted above the rear-view mirror. Shapes and contrast are captured by the sensors and processed by a module that filters out unwanted noise, like repeating patterns. Images from both cameras are compared, determining the distance to a potential collision. Subaru claims this aid works like a set of always-on human eyes, hence the name Eyesight. The system is networked into the Legacy's other subsystems (gas, brake, other sensors) to enable them with active driving assistance.
Eyesight is subject to a couple of limitations, and it naturally requires a clear view through the windshield. Fortunately, the cameras are placed within the reach of the wiper blades, so the technology isn't dependent on how often you wash your car. Weather and direct sunlight can cause visibility issues for the cameras, though. Additionally, low-contrast environments and repetitive patterns may also be problematic, since the cameras rely heavily on contrast.
Eyesight can completely stop the Legacy when it's moving at speeds of up to 19 MPH without driving input. Pre-collision will do this up to three times before disabling itself. At that point, you have to restart the vehicle for the system to work again. Subaru believes that if you have three close calls necessitating intervention, you need to pay more attention while driving.
Audible alerts do continue working at that point though, letting you know when a potential collision is detected. Throughout the alert process, the system prepares the brakes to apply maximum pressure without needing you to slam down on the pedal. The system expects you to react to alerts, and it backs you up unobtrusively.
The Eyesight pre-collision system's most useful application is its ability to cut throttle, preventing you from driving into a barrier. For example, imagine sitting at a stop light ready to turn right. There’s a car in front of you slowly accelerating into the same turn, so you follow suit. Suddenly, that person stops, as you're accelerating. Eyesight recognizes this and pulls the plug, preventing you from plowing into the car at full speed.
During our week with Subaru's 2013 Legacy 2.5i Limited, we didn't really get a chance to put Eyesight through its paces. There were a couple of instances where an alert popped up, but we were never traveling under 19 MPH, allowing the car to stop itself. Subaru also advised against having us stage an emergency situation to showcase Eyesight, suggesting the system might not react in time. This is one of those features that you hope to never have to use, and when the time comes, having it should be better than not.
Adaptive Cruise Control
Adaptive cruise control is one of our favorite driver assistance features. While most of the implementations we've reviewed up until now relied on laser sensors, Subaru employs the same cameras responsible for Eyesight. They're good at speeds as high as 87 MPH and capable of bringing the Legacy to a complete stop from the maximum velocity. The camera-based system isn't perfect, of course. Windy roads can trigger false warnings and unexpected braking. But we don't think this is too big of a deal; if you're on a windy road, enjoy the thing and don't use adaptive cruise control in the first place.
Because adaptive cruise control works from a complete stop up to 87 MPH, it makes driving in Seattle's stop-and-go traffic much more palatable. We simply set the cruise control to the 60 MPH speed limit and let the adaptive system work its magic. At a complete stop, it'd hold the Legacy still and disengage cruise after a couple of seconds, requiring a foot on the brake pedal. Once traffic started moving again, we simply lifted our foot and tapped the resume toggle; adaptive cruise was back in action at that point.
We enjoyed adaptive cruise quite a bit during our week with Subaru's 2013 Legacy 2.5i Limited. It made repeated trips to Seattle (and back) during heavy traffic much easier. Systems able to operate at a full range of speeds, such as the one found in the Legacy, have completely spoiled us.
Lane Departure And Sway Warning
Subaru's Eyesight package also includes lane departure and sway warning. Unlike the active system we looked at in 2013 Infiniti JX35: Getting Us One Step Closer To A Driverless Car, the Eyesight system simply warns you using annoying audible and visual alerts. As with most lane departure technologies, Eyesight's cameras monitor lane markers. If you cross a lane or sway side-to-side without using a turn signal, the warnings go off. The Legacy doesn't intervene, though. It's up to you to control the car.
We played around with the lane departure feature and didn't find it too bothersome. It really only sounded alerts when we rode the line between two lanes. To be sure, it was more reliable than the implementation we tested in Infiniti's JX35. Sure, it hit us with an occasional misread during rainstorms, but we expected that from a camera-based system. In comparison (and perhaps more problematic), the Infiniti version had more issues on sunny days. Fortunately, if you don't like the feature at all, you can turn it off with the push of a button.