When signs don’t work:
“Children at play” signs and the like are absolutely ineffective in changing a driver’s behavior, and studies of drivers through school zones show they were driving much faster than they remember. It’s been argued that signs allow us to basically stop thinking, and in certain places experiments have been done in which they’ve been removed, with no negative safety effects.
What behavioral economics tells us about it seems other lanes are always moving faster than ours:
But there’s a curious bias that plays out in oscillating shifts of traffic, observed by the researchers Donald Redelmeier and Robert Tibshirani, in which drivers, who are oriented towards observing things in the forward view much more than the rear, spend more time watching cars passing them than they spend watching themselves passing other cars.
Given the general findings that humans are more sensitive to losses than gains, it doesn’t seem a stretch to imagine that this sense of being passed — of the other lane being faster — would stick out in our brains. All you have to do is pick out a benchmark car in the adjoining lane to see how often we fall for this illusion. I’ve seen these cars pass well out of vision, only to find myself passing them again minutes later. Part of the reason this seesaw effect is happening in the first place is because of all the drivers ahead thought they could get a better deal, and basically ended up just shifting the equilibrium around temporarily.
And what technologies might help improve traffic choice architecture:
One technology that is quite clever and productive is the concept of “variable speed limits,” as seen on highways in England and elsewhere. Basically, if there’s a patch of congestion, it’s detected by sensors, and a new, slower speed limit is announced back “upstream.” That way, rather than having everyone drive at full speed into a traffic jam, which is neither good for safety nor traffic flow itself, the congestion shock wave is “damped.” Of course, people being people, you tend to have to have things like speed limit cameras there to make sure people go the suggested speed.