### An Optical Illusion May Cause Us to Speed and Not Even Know It

How long are those dashed lines that are painted on the middle of a highway, separating lanes? If you're like most people, you answered, “two feet,” but the real answer is – each one is 10 feet long! That’s the federal guideline for every road in the United States. How far is it between each line? Again, most people say two feet, but it’s actually 30 feet! Dennis Shaffer, a psychology professor at Ohio State University, thinks this discrepancy explains why we drive over the speed limit. Here are the details, courtesy of the science news website, Eureka-lert.org:

• When Shaffer asked hundreds of college students in three different states to estimate the length of the lines, almost all of them said two feet, and they weren’t answering from memory. They were actually riding in a car. When he asked about the distance between each line, he got the same answer - two feet.
• So, why do we all make the same mistake? Shafer believes it’s the result of an optical illusion. When we’re driving, we’re looking far ahead - so the lines appear smaller.

Now, we’ve all had moments when we looked at the speedometer and realized we were going too fast. Well, this study shows why that happens. Since we think we’re going four feet when we’re actually going 40, we underestimate our speed. Now, you might try passing this information along to the trooper if you get pulled over, but I wouldn’t count on it helping. If you really want to stay ticket-free, set your cruise control or check your speed every few miles.