Teenager Alerts Police That They Left Their Brights on -- 5 Minutes Later They Shoot Him Dead

[Xithras]

148. Here ya go...

Bottom half of this article discusses it.
http://www.mlive.com/news/index.ssf/2011/05/traffic_talk_should_you_turn_o.html

Or, if you want the actual law. Michigan Vehicle Code 257.700:
“Whenever the driver of a vehicle approaches an oncoming vehicle within 500 feet, such driver shall use a distribution of light or composite beam so aimed that the glaring rays are not projected into the eyes of the oncoming driver.”

The law goes on to say that the lowest light setting is excepted from the law, even if it actually causes glare. In other words, unless you have high beams that are so dim they don't cause glare, Michigan law requires you to turn your headlights to their lowest setting within 500 feet of another vehicle. And it doesn't contain any exceptions for "flashing".
http://www.legislature.mi.gov/(S(bug4bd2oikdkjjvlyms44bf3))/mileg.aspx?page=getObject&objectName=mcl-257-700

For what it's worth, I think the killing was entirely unjustified, but the original traffic stop was legal.