why doesnt this bus stop

yesterday my friend, Mr WW, had to go down to udupi(a town 20mins away from manipal) to have his bike repaired. after leaving his bike at the mechanic with a host of instruction,half of it the mechanic doesnt understand, he decided to take the public bus back to manipal. now Mr WW has never use the public transport before. not here. not in malaysia as well. so this is the first time for him. so his first instinct was to locate a bus stop which he managed quite succesfully. after waiting for 15 minutes or so, he saw a bus approaching. he immediately stood up. he noticed that the bus had no windows and had iron grills on the front windscreen. he felt a bit weird that a bus should be windowless but he brushed aside the feeling and tried flagging the bus. as the bus approaches, it showed no sign of slowing down. so he waved his hand even more frantically. as the bus approached even nearer, he saw two men in uniform laughing at him from inside the bus. and as the bus passed him he saw the words written on the side of it "Karnataka State Prison."