I would be willing to bet these police computers are using 802.11 MHz of 2.4, the same frequency that 802.11b and 802.11a use. I heard recently police can use 4.9MHz. Maybe the Keene IT guys don’t know?

Police Computers Clash With Dunkin’ Donuts System

For Keene, New Hampshire police officers, getting through the drive-through at Dunkin’ Donuts can be quite a nuisance.
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It turns out the officers’ in-car computers interfere with Dunkin’ Donuts computer system. Police using the drive-through have to disconnect their computer modems to avoid clashing with the restaurants’ system.