From MBTA.com's Red Line service alert page:

Subway Red Line - Alewife Station parking garage improvements will begin on Wednesday May 2, 2007 and these necessary repairs are expected to take approximately one year. Work will be performed between 10:00 p.m. and 6:00 a.m. to minimize the inconvenience to our parking customers. Portions of the garage may be closed to traffic or overnight parking will be prohibited in effected [sic] work areas.