City of Lowell issued the following announcement on Oct. 9.
Between October 15 and February 15, the leaf vacuum truck is in operation and you may stack your leaves, grass, shrub clippings in a neat row no more than 3 feet from the edge of the roadway. Please try to keep all sticks and rocks out of yard waste to be vacuumed.
Original source can be found here.
Source: City of Lowell