PORTLAND – Maine law enforcement agencies are joining a nationwide effort to crack down on seat belt scofflaws later this month.

Police agencies say the coast-to-coast Click It or Ticket campaign will feature random safety roadblocks. It will run from May 19 to June 1.

The National Highway Traffic Safety Administration says nearly one in five motorists doesn’t buckle up, and seat belt use is even lower at night. A NHTSA study found that 64 percent of the passengers killed in nighttime traffic crashes were not wearing seat belts.

Maine started cracking down on seat belt violators by fining first-time offenders starting in April. Before that, first-time offenders received warnings.