Believe it or not, optical illusion can cut highway crashes. Japan is case in point. It has reduced automobile crashes on 41 ______. some roads by nearly 75 percent using a simple optical illusion. Bending stripes, called chevrons (人字形), painted on the roads make 42 ______. drivers think that they are driving faster than they really are, and thus drivers slow down. Now the American Automobile Association Foundation for Traffic Safety in Washington D. C. is planning to repeat Japan’s success. Starting next year, the foundation will paint chevrons and other patterns of stripes on selected roads around the country to test how the patterns reduce 43 ______. highway crashes. Excess speed plays a major role in as much as one fifth of all 44 ______. fatal traffic accidents, according to the foundation. To help reduce those accidents, the foundation will conduct its tests in areas which speed-related 45 ______. hazards are the greatest -- curves, exit slopes, traffic circles, bridges. 46 ______. Some studies suggest that straight, horizontal bars painted across roads can initially cut the average speed of drivers in half. Then, 47 ______. traffic often returns to fast speed within months as drivers become used to 48 ______. seeing the painted bars. Chevrons, scientists say, not only give drivers the impression 49 ______. they are driving faster than they really are but also make a lane appears to 50 ______. be narrower. The result is a longer lasting reduction in highway speed and the number of traffic accidents.