PEABODY -- State Senate majority leader Frederick E. Berry of Peabody filed a bill Monday to have a special commission weigh the impact of the Massachusetts Port Authority's decision to stop the Logan Express bus service from Peabody on April 30.

Berry said he hopes the bill forces Massport to explain itself. ''I think people want to know how they came to their decision," Berry said. ''I've heard from many, many constituents on this who think Massport is not treating them fairly."

Danny Levy, a Massport spokeswoman, said the agency will ''await the outcome" of the Senate bill but noted the board is not likely to reconsider.

''We did all that we could to enable the Peabody service to continue," she said. ''It's unfortunate the numbers just didn't work out in our favor."

The 10-member commission would have until July 1 to report back to the Senate on the economic and environmental impact of stopping the bus service, which last year carried 87,500 passengers to Logan International Airport from a terminal on Route 1 south.

The commission, which would include the chief executive officer of Massport or a designee, would also review alternatives to closing the service, such as operating it on a limited schedule or contracting with a private company to keep the service going.

The bill, which must be scheduled for a public hearing before the Senate's Transportation Committee, also would prevent Massport from selling the land on which Logan Express is located until at least 60 days after the Senate receives the report. ''It's very valuable land," Berry said.

The legislation comes just a week after he and Peabody state Representatives Theodore Speliotis and Joyce Spiliotis sent a letter urging Massport to restore the service. The representatives have cosponsored the bill in the House.

The Peabody-to-Logan bus generally carried about one-third to one-fifth fewer passengers than Logan Express routes from Braintree, Framingham, and Woburn.

The Peabody route lost $1.5 million last year and has lost a total of $5 million since opening in 2001, according to Massport.

A round-trip ticket costs $22 for adults and $18 for senior citizens. Children younger than 12 ride for free. It costs $11 per day, or $66 per week, to park a vehicle at the lot.

Berry said the bus service also is key to reducing traffic and addressing parking issues at Logan.

''They're always talking about the need to take cars off the road," said Berry, who pushed to develop the Peabody bus route five years ago. ''And now they're taking away a bus service that does exactly that. It doesn't make sense."