MONTGOMERY — A new study shows that overseas military voters from 16 states and the District of Columbia are not given enough time to cast their ballots.

The study by the Pew Center says these states depend too heavily on slow mail systems to deliver ballots to voters and often don’t send out ballots early enough.

The study released Tuesday also says some states, like Alabama, require voters to have ballots witnessed or notarized. A researcher for Pew, David Becker, said that requirement can add several days to the process.

The study recommends that states streamline the process by sending the ballot to overseas voters electronically.