Why does a windscreen replacement now need a camera recalibration?
Because the camera for the car's driver-assistance systems is mounted on the windscreen, and moving it by a fraction of a degree moves where the car thinks the road is, hundreds of metres ahead.
What is behind the glass. Most modern cars mount a forward-facing camera — and sometimes rain, light and infrared sensors — in a housing bonded to the windscreen behind the mirror. That camera feeds autonomous emergency braking, lane keeping, lane departure warning, traffic sign recognition, adaptive cruise control and automatic high beam.
Why precision matters so much. These systems work by geometry. The car assumes a known camera position and angle, and converts what the camera sees into distances and lane positions. A small angular error at the camera becomes a large positional error at distance — which is the entire reason recalibration is not optional. A misaligned camera may brake for nothing, fail to brake for something, or steer towards the wrong lane edge.
Why the glass itself matters. The camera looks through a specific optical zone, and windscreens for camera-equipped cars are manufactured to tighter tolerances with a defined wedge angle and bracket position. A cheaper non-approved screen can pass visually and defeat calibration, which is a real issue in the repair market.
The two calibration methods:
Static, performed indoors against precisely positioned targets, on level ground, with the car at the correct ride height and wheels aligned straight.
Dynamic, driving at a defined speed on well-marked roads while the system recalibrates itself.
Some cars need both, and manufacturers specify which.
When else it is required: suspension work altering ride height, wheel alignment, bumper or grille repairs affecting radar, tyre size changes, and any impact to the front of the car.
What to check: that your repairer has the equipment and does it in-house, that approved glass is being fitted, and that you receive a calibration certificate. Insurers generally cover it, and an uncalibrated system can have consequences for both safety and liability.