yes, but I don't think it allows that.

Home rule lets a town/city make certain rules of their own.

Wrong, Home Rule is not mentiuoned in 12-215 of the Illinois Vehicle Code.

Greg is correct, but in a "home-rule" city, CSOs can have red and blue. A good example of this is Wheaton PD. Their CSOs drive SUVs w/ red an blue. The car above had red and blue in the rear window too. W.C. just went "home rule", so I don't know if they will change it or not.
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Amber lights might also be a way for a smaller department to "police" their own CSOs and preventing them from biting off a little more than they can chew. It's been my experience that many (NOT ALL) CSOs are younger males under age 25 with a fixation on being the police. To them, being a CSO is like the ultimate wannabe gig until they get hired as a sworn PO. They yellow lights on the cars will just naturally keep them in check and help avoid potential problems with impersonating.

Just my thoughts on the subject.

Greg
copcar dot com

Mike, I'm a police officer in So. Cal. and was just curious about the amber lightbar. Is this particular vehicle assigned to a "Community Services" officer or do they run amber lightbars on thier D.A.R.E. cars? Just curious.
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In Illinois, community service officers are not sworn police officers and therefore don't have the lawful authority to operate a vehicle with red/blue lights. They are civilian employees of the police department. They can not make traffic stops, but they do often direct traffic at crashes and fires so many PDs have red and amber lights on their CSO vehicles.

Greg
Chicago PD and
copcar dot com