Yes, if the officer has a reasonable suspicion you are armed and dangerous, she can frisk (pat down) you when you are pulled over for a traffic violation. Similarly, if the officer reasonably suspects that you are involved in criminal activity she can also perform a pat down. Assuming the police have probable cause -- a reasonable basis or justification to believe that you or your passengers are involved in criminal activity -- they can search your car and objects belonging to passengers.
Proof & Defenses in Criminal Cases
Getting a Lawyer for your Criminal Case
Steps in a Criminal Defense Case
Arraignment: Your First Court Appearance
Plea Bargains (Deals) in a Criminal Case
Legal Elements of Common Crimes
Expungement & Criminal Records
Should I just plead guilty and avoid a trial?
Is the public defender a real lawyer?
Can I change defense lawyers after I've hired one?
How long after arrest do I find out what the charges are?
Does it matter whether a suspect is given the Miranda warning?