Volunteer fire fighters...
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http://www.in.gov/dhs/files/driving_laws.pdf
These guys get pretty carried away with their vehicle lighting--plus they like lots of antennae. And, they often drive like crap. I mean, what's the point of the showing the lights if you have to drive the speed limit? I agree. I move over for them because they are off to do some public service. Truth is, though, by the time the volunteer fire dept shows up with their leaky 1960s pumper truck the conflagrating structure has been reduced to a romantic 18" bed of orange coals--suitable for roasting marshmallows and tingling the frosty toes.
What I've never seen, though, is the green lights for certified paramedics. Still don't have to give them the right-of-way though. Nobody would know what it meant if they saw a car spinning a green light on its roof. Maybe a meter reader or a pizza guy?