Those orange stickers on abandoned cars on Indiana freeways...

[Gfactor]

Apparently, Philadelphia doesn’t use the stickers anymore:

If, following the eleven day waiting period, the owner has not brought their vehicle into compliance with the law, the Police Department will make arrangements to have the vehicle removed. Please note that we no longer affix blaze orange “Abandoned Vehicle” stickers to reported abandoned automobiles.

http://www.ppdonline.org/rpts/rpts_abanauto.php

The rest of the link gives the details of the procedure for reporting and reclaiming an abandoned vehicle and notes:

Lacking resources or a means of properly disposing an unwanted automobile, some people elect to abandon them on city streets or dump them in other off-road venues. Doing so is against the law.

Vehicle owners of record may be held liable for towing, disposal and other fees related to removing their automobile. In addition to these fees, vehicle owners receive tickets for this violation that must be paid.

From the Oakland, CA police website:

The vehicle may have a Courtesy Warning Sticker applied to the windshield giving notice that the vehicle must be driven at least one mile within the next 72 hours. The Police Service Technician records the vehicle’s odometer reading and marks a tire for recheck after the 72 hours have passed. If the vehicle has not been driven one mile after 72 hours have passed, the vehicle will be towed.

http://www.oaklandpolice.com/geninfo/abauto.html

Foster City:

If the vehicle has not moved 1/10th of a mile after 72 hours has elapsed from the time the vehicle was first marked, it will be subject to citation, and a red warning sticker will be placed on the vehicle. The warning sticker informs the owner of the vehicle that it is in violation of a City Ordinance, and is subject to towing if it is not moved within an additional 72 hours.

http://www.fostercity.org/Services/safety/police/Abandonedvehicle.cfm