Crescent Street starts moving before six, and after a night of snow that traffic depends on a lot of people having already done their part. JB LANDSCAPING AND PLOWING SERVICES is one of them — plow down, driveways opened, walks shoveled, so nobody in Brockton is left standing in the road behind a bank of slush. In the green months those same trucks carry mowers, and the routine becomes weekly cutting, trimmed edges and the clearing that opens and closes the year. It is the same instinct in either season: get there early, leave it clean. That is a fair definition of looking after a street.