In the US, they're supposed to be 10 feet! Surprised? You're not alone. A study led by Dennis Shaffer at Ohio State University sought to discover people’s perceptions about the white dashed lines on roads. More than 400 college students were asked about how long they thought the lines were. The results were surprising, the students consistently underestimated the length of the line. They, like many people assume, thought that the lines were only about 2 feet long.
The study also found that people generally assume that the distance between the lines are the same distance long as the lines themselves. Even when people stood near the road and saw the lines from a distance, they still guessed that the lines were about 2 feet long on average. The reality is that each line in 10 feet long and the space between lines is a full 30 feet long! The significance of this data is that the perception that the lines are smaller may result from speeding.
It also means people are passing each other on the roads and assuming that they aren’t spending as long in the other lane, giving them a false sense of security. Do you think this misperception is dangerous?