Article on police lights, very informative

[CHPwannaBE]

http://www.policedriving.com/article145.htm

[PapaBear]

Years ago the department put out a safety memo to turn off all warning lights while on traffic stops as long as there was no immediate hazard. The department was experiencing too many rearend and sideswipe incidents when officers were on stops. Surprize! The accident rate went down! Slowly there has been a trend back to using warning lights by units on stops.

The flash rate creates what someone identified as the "Moth effect" and that causes motorists to become fixated on the light and inadvertently drive into the rear of the unit.

[Mac]

I worked a crash several years ago involving an allied agency unit on a stop on the freeway. The officer, after making the enforcement stop on the right shoulder, left all of his overhead emergency lights on. A DUI driver who had been driving in the #1 lane of the freeway succumbed to the "moth effect" that PapaBear alluded to, and crossed all four lanes of the freeway, drove onto the right shoulder and rear-ended the patrol car. It burst into flames and was burned to the ground. The officer was out of the car and uninjured, but had to return to the car to pull his civilian ride-along out of the burning car.

The DUI driver said the last thing he remembered before impact was seeing the police car's lights.

[NWTSCL]

Along this same line, I will often see CHP patrol units that are using flashing blue lights while using the directional stick in the left or right position in an attempt to direct traffic. The flashing blue lights create a powerful halo that distracts from the visual effect of the directional arrow, making it nearly impossible to see, especially at night.

Caltrans has a policy that all other rear-facing warning lights (other than required taillamps) must be turned off when using a directional arrow to prevent the blurring halo effect. Has the CHP considered this?