• schroedingershat@lemmy.world
    link
    fedilink
    arrow-up
    1
    ·
    1 year ago

    Generally guidance for “safe” following distance is to be able to stop before you hit a car that is also stopping with the assumption that the car ahead is stopping at the same rate. So 2 seconds of headway between cars (roughly reaction time alone). Obviously this does not give enough time if the car ahead has a head on collision or similar (but the third car will collide at lower speed and the fourth might stop).

    Most traffic is a little closer together than this (hence the prevalence of pile ups), but there is also uneven speed and gaps at traffic lights and similar