I kind of do this already. Taking a visual "snapshot" and then a few quick recitations finding patterns in the numbers, chunking them into pairs and threes if necessary, and I can have it in short term memory pretty quickly. Okay, I do it enough so that I know at least ten of my friends' license plates - when I wave at them driving by, it's 'cause the license plate jumped at me, not their faces.
HOWEVER... priorities, please! Three of us were resting off the road once... but not quite far enough off the road... when this car careens around a corner at us. Yours Truly thinks "A-hole! Let me get your license number!" - fortunately, my friends were hauling their bikes and butts out of the way when the driver clipped off a wheel, went across the street and mowed down a mailbox, veered back, stopped and then started backing up ... *then*, (having seen one too many Rockford Files episodes) I started across the cornfield, sure he/she/it was coming back to finish us off. (She wasn't.)
I realized I should have MOVED first... then gotten license plates:o :o .
Fortunately, a week later when a truck started coming right at me making a left hand turn and cutting the corner across my position in *my* left hand lane, I MOVED and he only clipped my basket. (Oddly, before or since, I have not been struck.)

