Remember that tantrums are not naughtiness.
He is having emotions that he is having difficulty controlling (because he's only 17mo old!). Try to be empathetic to his emotions, and vocalise them.
For example, "It sounds like you feel really frustrated that you can't play with your push chair on the bus, and cross with mummy for stopping you." Give him big hugs, if he will let you.
If at home, isolating (for a minute or two) can work really well, if it's viewed as a chance for him to calm down, rather than a punishment for being naughty. This can be a good strategy for children as they get older, and even adults. Ie walking away from the situation to calm down.
DD2 had terrible tantrums well into her 3s, and l had an informal chat with a child psychotherapist that I know through work about her. (i was by this stage considering professional advice, as it was so bad.) She said that all behaviour is for a reason, and it helps to try to find the reason for the anger.
I feel so guilty now that I was not more accepting of the emotions raging within her. 