A survey by USA’s Insurance Institute for Highway Safety (IIHS) revealed that about half of cars equipped with advance driving aids systems (ADAS) features that for whatever reason, required repairs, no longer work properly after repairs were made.

ADAS is a generic term for an umbrella of driver assistance features like frontal collision warning, autonomous emergency braking, or blind spot monitoring.

“Most of the more than 3,000 owners we contacted said they had never needed to have their crash avoidance features repaired, but for the minority of owners who did, the problems weren’t always resolved easily,” said IIHS Senior Research Scientist Alexandra Mueller, who designed the survey. “Many had issues with the technology afterward, and some said they had to have the same feature repaired more than once. Still, the vast majority said they would buy a vehicle equipped with the technology again and most were satisfied with the out-of-pocket cost.”

The IIHS estimates that a simple windscreen replacement can cost around USD 250. But a separate study by IIHS-affiliated Highway Loss Data Institute (HLDI) found that vehicles equipped with front crash prevention were much more likely to have glass claims of USD 1,000 or more. Much of the higher cost is likely related to calibration.

“About two-thirds of owners whose crash avoidance feature repairs involved windscreen replacement and nearly three-quarters of those whose repairs were required due to crash damage said they had issues with the technology after repair,” said IIHS.

The insurance organization adds, “However, the higher incidence of post-repair issues for repairs that involved calibration suggests that repairers are struggling with the calibration process. Some calibrations are complicated and require large spaces, specialized training and expensive equipment. Calibration software is subject to frequent updates, making it difficult for shops to keep their tools up to date. This is further complicated by a lack of standardization of calibration processes. Institute researchers are tracking these problems to monitor whether they persist or diminish over time.”

All frontal collision avoidance features - autonomous emergency braking (AEB) and frontal collision warning (FCW) rely on cameras fitted behind the rear-view mirror, glued to the windscreen. This is a high precision distance measuring device and it’s impossible to remove it by hand and install it back to the factory’s specifications.

This is also the same for blind spot monitors, many of which rely on radars hidden behind the rear bumper.

In some cases, fitting overly large size tyres, or adjusting the vehicle’s suspension ride height (beyond reasonable limits) could affect its accuracy.

Calibrating the ADAS require special tools that few independent workshops will want to invest in.

Closer to home, Perodua confirms that all models equipped with PSDA / ASA will need to undergo a system recalibration process once the windscreen has been replaced.

“To our knowledge, only Perodua Service centres can calibrate the sensor when changing the windscreen,” said the company’s spokesperson.

TC Subaru said, “Yes, EyeSight needs to be calibrated using special tools after the windscreen is replaced.”

Honda Malaysia said, “After replacing to a new front windscreen, the camera needs to be recalibrated. Proper calibration of the camera is necessary for the system to operate properly.”

Also, take note that many cars today now come with noise reducing acoustic glass, so these windscreens will cost more and replacing it with a cheaper non-original item might result in a slightly noisier ride.

On cars fitted with Head-Up Display (HUD) – the ones where the image is projected directly onto to windscreen rather than a simple flip-up plastic – the windscreen needs a special coating on it to allow the image to be projected clearly, so keep this in mind if you want to save some money on a cheaper glass instead of a more (sometimes a lot more) expensive genuine replacement part.