Ridership on the Logan Express bus route from Back Bay Station to Logan Airport doubled in June compared with the same month in 2018, following fare reductions and the introduction of an incentive that allows riders to bypass conventional security lines.

That’s according to the Massachusetts Port Authority, which dropped the Back Bay-airport fare to $3 from $7.50 on May 1, and made the airport-Back Bay run free. The agency also on May 1 introduced vouchers for riders that allow them to use a dedicated security line. The move was thought to be the first of its kind in the U.S.

Because of the bounce in ridership, Massport is now mulling over Logan Express locations, including near North Station, per the Globe’s Jon Chesto. It’s unclear if the agency would offer riders the same incentives as those for Back Bay Station. (We also have an email out about exact ridership figures for the Back Bay-airport route.)

Related The ultimate guide to Logan Airport

The Back Bay-airport route itself was a change—for better T and commuter-rail connection—as Logan Express used to pick up from Copley Square.

The changes and the possible changes are all part of a Massport effort to mitigate and publicize worsening construction-related congestion at Logan Airport. New England’s largest transportation hub is undergoing numerous infrastructural changes, including an expansion of Terminal E and roadwork between terminals B and C.

It’s all in anticipation of a drastic jump in passengers: Some 47.6 million a year are expected to pass through Logan by 2024, Massport says, a 17 percent increase from 2018.