GMATPrep错误题目请教

Many small roads do not have painted markings along their edges. Clear edge markings would make it easier for drivers to see upcoming curves and to judge the car's position on the road, particularly when visibility is poor, and would therefore seems to be a useful contribution to road safety. However, after Greatwater County painted edge markings on all its narrow, winding roads, the annual accident rate along those roads actually increased slightly.
Which of the following, if true, most helps to explain the increase in accident rate?
A.Great water County has an unusually high proportion of narrow, winding roads
B.In bad weather it can be nearly as difficult for drivers to see the road as it is at night
C.Prior to the painting of the edge markings, Greatwater County's narrow, winding roads already had a somewhat higher accident rate than other Greatwater county roads.
D.Many of the accidents on narrow, winding roads involve a single vehicle veeriing of the road, rather than the collision of two vehicles
E.After the markings were painted on the roads, many drivers who had gone out of their way to avoid driving on those roads at night no longer did so.

Answer:E. I don't understand

E says that after the markings were painted, many drivers thought that it was safe to come back and drive at night. That was what they did. That's the reason why more accidents happened.

Hence E is correct.