More data is coming in that shows electronic safety systems – especially automatic emergency braking – really do cut accident rates.We reported on the first UK data about this in April, but new data has now emerged from the USA. The federal Highway Loss Data Institute (HLDI) says that accident rates were 14% lower in cars fitted with Autonomous Emergency Braking (AEB) – what Ford calls City Stop.It said warning systems that alerted the driver to an obstacle but did not brake the car showed less improvement. We are not surprised about that – such systems tell you via a light and a noise that something is wrong, but you then have to take a fraction of a second to figure out what the message is all about. If you have not already noticed the obstacle, it is probably then too late.