Legal Question in Traffic Law in Missouri

Re: passenger in a vehicle

An officer can ask you whatever he or she wants...it is not against the law to attempt to solicit information... if a person voluntarily offers information, they cannot claim they were coerced unless you have flagrant conduct. Just because the officer asked for your license does not mean you necessarily have to provide it. However, to the extent the officer has a "reasonable belief that criminal activity may be afoot," he or she may be able to ask for ID or frisk someone down for a weapons check without a warrant where reasonable suspicion warrants the intrusion.

So my answer is "it depends." If the officer has reasonable suspicion to believe you had committed some offense separate from the driver's speeding violation, it may justify a search.