Since last July, community members unhappy with traffic, pollution and too few jobs in Somerville have been working to extend the Green Line to Union Square. Last summer, more than 300 Somerville residents sent in letters to ask for better transportation.

Ironically, just as the community has begun to demand better service, the transportation system is about to get worse. As part of the MBTA's work to upgrade North Station, starting June 19 the Green Line will be closed from Government Center to Lechmere. The closure will last at least 12 months.

The closing of the Lechmere stop will affect everyone who rides the 80, 87 or 88 bus to Lechmere and then takes the train into Boston. The closure will also mean more pollution in our lungs, since the MBTA intends to replace train service with heavy-duty diesel buses.

For Green Line riders, the bus substitutions will add 40 minutes or more to their daily commute. The buses will have to wade their way through busy traffic along the Museum of Science bridge and through downtown Boston to Haymarket and then Government Center, where riders can get off or transfer onto the still-working parts of the Green Line.

Faced with long bus rides, many riders will choose to travel in other ways. Some will take the 85 bus to the Kendall MBTA. Others may make use of the Orange Line. A good number will also choose to use their cars, adding to the already difficult traffic situation.

Unfortunately, that's not all. Because of a separate project, the Orange Line will soon be shut down five nights a week after 9 p.m., also with bus service replacements. Simultaneous ongoing roadwork at Leverett Circle, where Storrow Drive meets the Big Dig, makes the overall situation still worse.

The reality is that Somerville and Cambridge deserve better. The MBTA reports to the governor and the state legislature. The state has been legally required to extend the Green Line since 1990. While the first planning study is finally beginning, no one at the state level has stepped forward to make sure the project is fully funded. Now, Somerville faces a near "perfect storm" of new transportation headaches.

While we press for the extension to go forward - and for other improvements to Somerville's transportation system as well, like an Orange Line stop at Assembly Square - we must also demand better treatment from the MBTA during the Green Line shutdown. The community deserves good transportation, including: