If a police officer wishes to search your vehicle, inquire as to why. If you don’t want the search to proceed, clearly state that you do not consent to the search. Denying a search is not an admission of guilt. Usually the officer is only allowed to conduct the search of your vehicle if you offer consent; the officer has probable cause that the vehicle contains incriminating evidence; of if the officer believes they must search the car for their own protection.
If you are stopped for a traffic offense, such as speeding, the police officer usually does not have the right to search your car. However, if your violation requires you to be taken into custody, the search is usually allowed.