Student or Learner
I don't get what "discrepancy" here means. Does it mean in fog, we don't recognize the difference between cars speeds or what? What causes car crash in fog?
When fog rolls in on a highway, the result is often a huge, multicar chain-reaction crash. An incident that occurred in 1998 near Padua, Italy, involving more than 250 cars, is an extreme example of a rather common condition....
He shows that when a pair of boxes - one colored light, the other dark - are moved across a background of black-and-white stripes, the dark box seems to move faster when it crosses the white sections, while the light-colored box appears to go faster as it crosses the black sections. The higher the contrast, the faster the apparent motion, so even though the two boxes are moving at the exact same speed, they look as if they are taking alternating steps.
In fog the contrast of cars, not to mention the surrounding landscape, is reduced. Everything around us appears to be moving more slowly than it is, and we seem to be moving more slowly through the landscape. The idea that we are not aware of this discrepancy is suggested in studies showing that while drivers tend to slightly reduce their speed in foggy conditions, they do not do so by enough to ensure a safe margin. Ironically, drivers may feel more comfortable staying closer to the vehicle ahead of them - so that they do not "lose" them in the fog - but given the perceptual confusion, this is exactly the wrong move.
Last edited by keannu; 20-Sep-2012 at 10:00.
(Not a Teacher)
I believe "discrepancy" here refers to the fact that, in fog, we think we're moving more slowly than we actually are due to low contrast, causing us to not put enough distance between ourselves and the vehicle in front of us.