Cars and Safety

As I was driving home last night, I noticed the brake lights of the car in front of me. Something just did not look right. The car had only two rear brake lights; the third brake light in the center of rear window was missing!

The third brake light, also known as a "Center High Mounted Stop Lamp" (CHMSL), was implemented by the National Highway Transportation and Safety Administration (NHTSA) on all cars manufactured since 1986 and on light trucks since 1994. Did CHMSLs actually improve safety on the roads?

The NHTSA website contains long technical reports about the effectiveness of CHMSLs. It affirms that CHMSLs were most effective soon after the lights were required. In 1987 and 1988 CHMSLs reduced the number of rear collisions by 8.5% and 7.2%, respectively. Soon after, its effectiveness decreased. Between 1989 and 1995 there was a 4.3% reduction of rear collisions. Perhaps the average driver was accustomed to seeing the third brake light, failing to provide the extra caution that it did once before.

Maybe Red CHMSLs are not the best color. Research from Taiwan has indicated that those tested in driving simulators responded fastest to blue lights. Perhaps changing the color will further reduce rear collisions?