...in the parking lot of Alewife Station!
Every work day, between the hours of 5-7pm, commuters not only sit in their cars on the roads around Greater Boston, but also in parking lots. Alewife's main parking lot offers 4 levels of parking, on most days, the queue to pay & exit extends to the 3rd level. In this pic, you can see the headlights of the cars waiting on the first 2 levels.
The road on the far right is where Route 2, 3 and 16 meets in Cambridge.