[verytrivial]

Blocking the view of other roads that also converge on an intersection can have the perhaps surprising effect of reducing accidents, or at least the severity of them. Removing the view of other cars forces drivers to slow down and check when much closer to the intersection. I'm guessing it also reduces lead-foot hubris, but won't stop outright intersection-gamblers. Not all taxes are bad.

(I can't find a reference after an admittedly lame search attempt, sorry!)