If the driver of car 3 could not see past car 2, and car 2 hadn't realised the Tesla had stopped, and instead swerved out the say 1 second / 90 feet (assume 60m

If the driver of car 3 could not see past car 2, and car 2 hadn't realised the Tesla had stopped, and instead swerved out the say 1 second / 90 feet (assume 60mph) before collision, that would give car 2 traveling at a reasonable gap no more than 3 seconds / 270 feet to recognise what was going on and stop. Should have recognised something odd (a broken down car) within 1.5 seconds, leaving 1.5 seconds to slow down. Applying brakes from 60mph would mean you'd still be traveling over 40mph when you hit the back of the car. Thus you need to give more than 2 seconds if you can't see beyond the car in front