The Stoughton (Mass.) Police Department is affixing QR codes on each front fender of its police cruisers, according to the department's website. QR codes are black and white images that users can scan with a smartphone.
Once scanned, a smartphone user will then be taken directly to a website on their smartphone's web browser, in this case the police department's website. The department said the goal of the program is to allow citizens to offer tips or comments.
You can see images of the QR codes on the vehicles in this article on the Patch.com local news website for the city.