Recently, many traffic lights and street markings were temporarily removed from a heavily traveled street in a major metropolitan area. Given that this street experiences significant volumes of automobile traffic, the number of accidents on the street was expected to increase. However, even though the street experienced no reduction in traffic, the number of accidents was greatly reduced. Which one of the following, if true, most helps to resolve the apparent conflict described above? ['Traffic lights and street markings are intended to have benefits in addition to those related to safety.', 'Most drivers were not aware that traffic lights and street markings had been removed.', 'Drivers were given advance notice that the traffic lights and street markings would be removed.', 'The lack of traffic lights and street markings caused drivers to drive more cautiously.']