The truth about Subaru EyeSight windscreen damage
I have been looking at the Subaru Outback with EyeSight. I have been scared off the car after reading local as well as US Subaru blogs where there are numerous complaints about rapid cracks in the windscreen from a minor stone chip, etc. In one case it cost one owner $2400 to have a windscreen changed and EyeSight re-calibrated.
Have you had any other queries about this EyeSight windscreen issue or what might be the problem? - Yew
This answer features in my regular show on YouTube (right), in which I answer your questions. Pay the video and scroll to 25:15 if you don't feel like reading - you'll get the full answer in under two minutes.
I simply have not heard of this problem. Frankly I don’t see how Subaru's EyeSight system can make a windscreen more vulnerable to cracking - that’s ridiculous.
Obviously if any windscreen gets chipped then the outer layer of glass is vulnerable to crack propagation.
What is Subaru EyeSight?
Subaru EyeSight is a camera-based that uses two cameras (for range-finding) together with smart software to identify threats. It warns the driver and can also brake the vehicle autonomously, either to avoid impacts or mitigate them. It's also used for adaptive cruise control functions.
Windscreens are laminated - a sandwich with glass as the 'bread' inside and out, but a layer of polycarbonate in between. This prevents shards of glass from cutting you in half in a crash (good) and also allows you to see the road ahead if a rock hits the screen (also good) and lastly really helps that rock not come through and hit you in the head at 100km/h (trifecta of good things right there). Tempered glass (think: every other window in the car) is tougher in respect of resisting breakage, but breaks into a million pieces when it finally breaks because the heat treatment process wracks it with internal stress.
However, once a crack forms in a material like glass, propagation of that crack (getting longer and longer) soon after is practically a formality - from temperature changes or dropping the wiper blades, etc. Mechanical shock can do it, too - such as driving over a bump at the right/wrong frequency/displacement.
EyeSight & Windscreen Damage
But in this respect a Subaru EyeSight windscreens are no more vulnerable to damage than any standard windscreen. The cameras are on the inside, and the problem always starts on the outside. Clearly.
Certainly EyeSight windscreens do cost a lot to replace and recalibrate. (The position of the cameras relative to the car is critical, obviously.) In the same way, any car with adaptive cruise control using a radar in the grille costs a lot more to repair in a minor frontal crash too. If I were you I would certainly choose a comprehensive motor vehicle insurance policy that included windscreen replacement, just for peace of mind.
I think your analysis misses out on the fact that EyeSight is an excellent system. A lifesaving system. Obviously the repair cost is a tradeoff - but if Eyesight allows you to avoid even a minor crash - panel damage only - then imagine the money it will save you. If it saves your life or prevents injury - incalculable return on investment there.
But frankly I think these complaints you've seen online are a complete beat-up. they're far more likely to be the result of a conventionally broken windscreen (which would have occurred anyway, EyeSight or not) followed by the owner being monumentally unimpressed at the cost of replacement and recalibration, rather than any intrinsic additional vulnerability to cracking of the EyeSight windscreen itself.