How come police swat teams do not use tanks?

Answer 1

Tanks are slow. Their swat vans get to the scene quicker. Plus, can you imagine the pandemonium if a tank came rolling down a public road? People would think WW3 started. Tanks are also more expensive to operate, it would be a bad financial decision for any police department to use them when they are not cost effective.

Answer

Also, tanks aren't effective in urban environments, which are the major area of operations for most SWAT-type teams. Armies, quite aside from police, have found armoured operations limited in urban and built-up areas. Armour is more suited to open countryside. It's worth noting too that tracked vehicles cause significant damage to tarmacadam and concrete roadways, and they generally need to be towed, usually behind a dedicated "tank transporter" to the required location- they are generally too slow, use too much fuel, and can suffer from mechanical problems if required to move long distances under their own power.

Answer 2

Police forces are tasked with maintaining the peace, which means apprehending suspects without large scale destruction of property or loss of life. Those results are difficult to avoid when using the kind of heavy weapons you specify. You've seen one too many action movies. My cousin is in the SWAT Team for Vancouver, B.C., and they do really try to talk the person(s) out of the situation, but always have a good aim on their target. They will use tear gas and also dogs. By using the weapons you mentioned that could injure innocent by-standers or shopkeepers and possibly blow out half a city block.