Also, collecting a 64GB i<device> over USB will take at least 24 minutes. (You don't really just want the photos, do you.) That makes for a long traffic stop.
Also, what the hell are you doing turning over your phone to police officers during traffic stops......
There are several reasons that one might turn over one's phone, all well documented in the media. The primary two are:
1) Voluntary cooperation with a request 2) Search incident to arrest
(Obligatory WTF on downvoting: I point out reasonable information and a technical challenge with doing this in the field based on personal experience as a forensic examiner, and I get downvoted?)
(I didn't downvote you)