Serious bummer . . .there are several GPS-based tracking products that can be concealed in your car and activated - - issues are size, battery life, satellite or cellphone text band triangulation and finally, the permissable laws in your state.
I understand that some states may have privacy issues with such devices--presumably, the car is in your name, it's a spouse or child not a business intelligence effort, etc. So be sure and do some research before taking action. You might even talk to your local police and position it as a child-safety move - - -same principle.
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