<p>Planning ahead for getting across the border this weekend -- the traditional start of heavy summer cross-border travel  -- may spare motorists the unwanted angst of a traffic jam. That's the  advice from U.S. Customs &amp; Border Protection officials who are  gearing up for the upcoming Memorial Day weekend. "Travelers are  reminded that as of Jan. 31, 2008, CBP stopped accepting an oral  declaration of citizenship and now all individuals entering the country  have to present documentary proof of citizenship," said CBP Chief Ron  Smith in Detroit. Documents that can be used to gain entry into the U.S.  include official passports, passport cards, copies of birth  certificates along with government-issued photo identification, enhanced  driver's licenses, NEXUS or FAST cards. Those U.S. or Canadian citizens  who travel without the correct paperwork will have the requirements  explained to them, receive a tearsheet explaining how to become  compliant with the rules and then be able to proceed into the U.S. CBP  officers are still exercising discretion with those who fail to comply  with the enhanced requirements in order to ensure that everyone knows  what is required. Since the standards for entry were increased earlier  this year, the compliance rate among travelers crossing the border has  been in the 90 percent range, according to U.S. Department of Homeland  Security officials.</p>