According to the publication "A Guide to Naturalization", M-476 on page 25:
"If you have been arrested or convicted of a
crime, you must send a certified copy of the
arrest report, court disposition, sentencing,
and any other relevant documents, including
any countervailing evidence concerning
the circumstances of your arrest and/or
conviction that you would like USCIS to
consider. Note that unless a traffic incident
was alcohol or drug related, you do not need
to submit documentation for traffic fines and
incidents that did not involve an actual arrest
if the only penalty was a fine of less than
$500 and/or points on your driver’s license."
It won't let me post the link..