I work for a municipality as well, and all the buildings are tobacco free (no smokeless tobacco either); as are the vehicles. There are individuals that work for the city that smoke cigarettes so they're expected to smoke on their designated union breaks/lunch; however, the city isn't so strict that if the person sneaks in a quick cigarette break here or there they're going to be in trouble unless it became a problem affecting their performance.
With that said, I work for the Police Dept. as an Animal Control Officer, so I have no scheduled breaks or lunch. I take breaks and lunch between calls. I have in the past carried a small pouch with some cigarillo's or a cob with some aromatic tobacco for those times between calls if I felt the need for a pipe or mini cigar. One of my Police Sgt. used to smoke cigars, so on those rare quiet days we would smoke a cigar together outside the station. Those days were few and far between though. Without knowing when the next call would be it makes it hard to smoke, so I usually only do it on the days I work nights when it's typically more quiet, and I felt I wouldn't be interrupted. I rarely smoke at work and typically only do so when I've been buried by a long report and need to escape the office and take a break from my computer.