YPSILANTI, MI – Subaru is rolling out a suite of new safety technologies, but they come with a disclaimer – actually, several.

The system, called EyeSight and available in the U.S. since July on the refreshed ’13 Legacy sedan and Outback cross/utility vehicle, uses two forward-facing cameras mounted on either side of the rear-view mirror to enable technologies such as adaptive cruise control, pre-collision braking and lane-departure warning.

During a recent demonstration at historic Willow Run Airport here, the technology works as advertised, but only after David Sullivan, Subaru’s car line manager, explains the system’s limitations:

  • It functions by identifying vertical surfaces and contrast, so a fallen tree or pedestrian lying across the roadway may not be spotted, nor would a person dressed in white walking along the road in the snow.
  • A speed differential of more than 20 mph (32 km/h) will render the system inactive, so a car traveling 40 mph (64 km/h) will not have time to apply full brake pressure if another vehicle is traveling the same speed toward a head-on collision.
  • The system needs about 2.5 seconds to react when an object comes into range. For instance, a deer darting right in front of a car will not trigger full braking.
  • The plastic lens caps cannot be touched because smudges will cause a malfunction. Subaru recommends plastic kitchen wrap be applied when cleaning the inside of the windshield.
  • If the windshield cracks, a Subaru-spec replacement must be installed for EyeSight to continue working properly.
  • EyeSight’s view at night is limited by the range of the headlights.
  • When off-roading, do so with windows and moon roof closed, to prevent excessive dust from tainting the camera vision.
  • Heavy rain and snow may temporarily disable the system.

“You have to remember, the technology can only do so much,” Sullivan tells journalists before the drive.

“There are technical limitations to what computers, cameras and processing systems can do at this point. If you are driving crazy on a suburban street and someone walks in front of you, the system can’t react that fast. The system is not capable of doing everything for the driver.”

Despite the admitted foibles, Sullivan says about 10% of Outback and Legacy Limited buyers are ponying up $1,295 for the device.

The only way to get it is on a technology package that includes navigation and moonroof, priced altogether at $3,690 for the Legacy and $3,645 for the Outback. With EyeSight, Legacy pricing starts at $29,585, while Outback pricing begins at $33,035.

By ’14, more low-priced Subarus will offer EyeSight, and Sullivan says he hopes higher installation rates will drive down the price.

Active-safety technologies such as these have been demonstrated and in development for years by suppliers such as Continental, Bosch and TRW, using radar and other types of sensing.

Production luxury vehicles, beginning several years ago with the Mercedes S-Class and BMW 7-Series, have been rolling out pieces of the technology as it improves and becomes less expensive.

Its integration on two of Subaru’s most popular vehicles represents a significant coming-of-age for the technology, particularly because buyers face an all-or-nothing proposition: There’s no picking and choosing of, say, adaptive cruise control, while leaving off pre-collision throttle management.

The remaining components making up the 7-piece package are pre-collision brake assist, lane-sway warning and lead-vehicle start alert.

Volvo, a brand synonymous with safety, has embraced a similar philosophy with its City Safety technology, which uses a laser sensor positioned near the top of the windshield to monitor low-speed traffic in front of the vehicle.

The all-new V40 wagon features an upgraded version of City Safety, which is active at speeds up to 31 mph (50 km/h), up from 19 mph (30 km/h) on the previous generation. Volvo says the technology automatically brakes if the driver fails to react when the lead vehicle slows down or stops, or if the car is approaching a stationary vehicle too quickly.

The Insurance Institute for Highway Safety reported in a 2011 study the Volvo system reduces collision frequency up to 22%.

Sullivan says Subaru’s EyeSight system, which was introduced in Japan in 2007 and launched last year in Australia, has a forward camera range of 87 yards (80 m) as well as a 25-degree horizontal view and 13-degree vertical view.

The cameras scan the road ahead every 0.10 seconds, and the distance to the lead vehicle is calculated based on the lateral distance between the two images.

The stereo black-and-white camera image is networked into the vehicle to communicate with steering-angle sensors, wheel-speed sensors, throttle control, brakes and electronic stability control.

As an example, Sullivan says an EyeSight-equipped vehicle traveling 65 mph (105 km/h) will recognize another vehicle in the same lane doing 50 mph (80 km/h).

“Let’s say you do nothing. You’re texting away, distracted. EyeSight is in the background looking for obstacles,” he says. “If you do nothing, it senses and calculates you will hit that obstacle, and it will start to intervene.”

First will come an audible warning, followed by light braking applied by the system. If the driver remains oblivious, braking will become progressively heavier to the point of full stopping power, if necessary.

“If you wake up and decide to do something, it gives you back control of the vehicle,” Sullivan says. “This is our core philosophy: We always want the driver to have control. If it starts to brake and you take over and swerve, or you hit the brakes, it will not override your inputs.”

However, the speed differential of 20 mph limits the system’s ability to react in many dangerous situations. For instance, an EyeSight-equipped vehicle traveling at 70 mph (113 km/h) won’t recognize until the last second that it is approaching another vehicle in the same lane going much slower, say, 30 mph (48 km/h).

“The system will probably initiate braking, but it won’t avoid a collision,” he says.

What sounds like a fundamental flaw actually is the norm for these types of systems, which are intended to supplement – rather than supplant – the abilities of the driver.

In fairness, the City Safety system on the more expensive Volvo has an even more restrictive speed differential of 9 mph (15 km/h).

Sullivan says Subaru plans for its third-generation EyeSight system, now under development, to incorporate a wider speed differential and to be more robust by reacting to a broader range of traffic situations. “But the philosophy is, we will always give the driver back control.”

On open tarmac here at Willow Run, two simple maneuvers demonstrate EyeSight’s ability to bring a vehicle to a complete stop. A leap of faith is required while coasting in a Legacy at 20 mph toward a large foam block bearing an illustration of an Outback rear end, as if in traffic.

Without fail, the system stops the Legacy every time, although the temptation to hover the right foot over the brake pedal is overwhelming.

In another test, the vehicle begins to brake if the Legacy is closing in on the foam wall, but then full control is given to the driver if he swerves at the last second to avoid a collision.

The EyeSight system has some tremendous attributes. True, radar-based devices can see farther in front of a vehicle, but cameras provide a wider viewing angle, allowing EyeSight to track and react to threats from adjacent lanes.

Also, Sullivan says radar systems tend to provide too many false readings and generally struggle to identify non-metallic items ahead.

EyeSight’s adaptive cruise control functions at vehicle speeds up to 90 mph (145 km/h), while pre-collision braking can work up to 99 mph (159 km/h). The system also can be shut off at any time.

Sullivan says pre-collision brake assist adds brake force when the driver does not apply enough pressure on the pedal to avoid a collision, if EyeSight calculates one will occur without further intervention. This is the only case in which EyeSight will override a driver’s input.

Subaru is not a premium brand, but it walks a fine line between high volume and luxury.

Its adoption of EyeSight will expose active-safety technologies to a broader pool of consumers, who will need to learn what the system can and cannot do the same way they discovered how to use personal computers and smartphones.

Distracted driving is a severe and dangerous problem on American roads, but Sullivan says no one should view EyeSight as a device that will make it safe to text while behind the wheel and that no technology will save a texting driver from his own dangerous behavior.

“I can’t solve texting. That’s a societal issue, not something Subaru can solve by ourselves,” he says. “I don’t believe that putting this technology on the car will make a mom more likely to text while she’s driving with her kids.”

Meanwhile, Subaru is planning to make EyeSight available on all of its car lines in the future, after the third-generation system is available.

No word yet on timing for generation three, but count on fewer caveats.

tmurphy@wardsauto.com