In  2022, cars in many countries must start carrying automatic emergency braking…

The European Transport Safety Council, a not-for-profit advocacy group in Brussels, estimates that automatic braking can reduce traffic death rates by as much as 20 percent. That’s about 4,000 lives saved each year.

The system—which uses cameras or radar to tell when danger’s up ahead and, if need be, hits the brakes—will be required in May in the European Union. In the United States all models that are new in 2022 come with it, although compliance is voluntary, pending formal rulemaking. Similar rules are also going into effect this year in dozens of other countries.

The EU’s regulations, conceived in 2019, seem to go the furthest, requiring as they do a number of other advanced driver assistance systems—notably emergency lane-keeping assist, drowsiness and distraction recognition, and intelligent speed assistance.