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Can you tell me how old your son is please.
Thank you for the information.
I am sorry to hear about the problems you are experiencing with your son. At this age he is beginning to be more interested in the outside world, for instance what is coming next and the routes to get places. This may mean that when he is faced with something different from what he expected it may cause him to feel uncomfortable or a bit out of control. You may be able to understand it if you consider how you might feel if when you made a turn onto a street that you normally turn on you found it barricaded closed. It might cause you to feel surprised and perhaps irritated or angry.
One way that you can deal with this is to, when possible, give your son a "heads up" about the plans shortly before they happen. For instance, when driving to the pizza shop you might casually say, "We're going to go a different way today." This may allow him to understand that this is not an accident or anything frightening. If this is not effective then you can work on responding to his behaviors in a therapeutic way. Keep in mind that any behavior that gets attention is likely to continue happening. It has been called the law of the soggy potato chip in that if a child thinks that he has a choice between a soggy potato chip or no chip at all, he will choose the soggy chip. If your son gets attention for having these tantrums or outbursts, he will choose the negative attention and so he will act out until he gets it. The only way for this pattern to stop is to begin to catch the good behaviors and reward them with attention, and to calmly and matter of factly give consequences for the negative behaviors with as little attention as possible. A very good book on this subject is Win the Whining War & Other Skirmishes: A Family Peace Plan by Cynthia Whitham MSW. The more consistent you become with this positive parenting, the more secure your son will begin to feel and the more his behavior should improve. I hope this answer is helpful. Please let me know if I can clarify further.