As I said in the comments above, the single most effective measure for reducing accidents would be checking for alcohol- or drug-influenced drivers. Those cause much more accidents than mechanical failures.
Yet even though "alcohol-locks" have been mature tech for five years, no car manufacturer nor politician dares to make it default, simply because there would be public outrage.
Also, stuff like brake pads or tires completely worn down already comes with basic safety features: both will cause the car to make relatively loud, screeching/rumbling ominous noises.
Well, current-gen tech is. But an AI/camera based version that quickly checks your pupil dilation when you put the engine in gear could work just fine. It could also catch drugs other than alcohol.
Or you could do near-infrared spectroscopy built into the gear lever (this is already being pushed by the NHTSA, and will probably be in cars in a few years).
Or it could even have a selective alcohol-lock using current-gen tech that only triggers a check if alcohol is detected in the air circulating in the car.
Yet even though "alcohol-locks" have been mature tech for five years, no car manufacturer nor politician dares to make it default, simply because there would be public outrage.
Also, stuff like brake pads or tires completely worn down already comes with basic safety features: both will cause the car to make relatively loud, screeching/rumbling ominous noises.