Cycle tracks, beginning and end of

In a previous post on cycle tracks (segregated cycling lanes set back from the general motor vehicular traffic, sometimes protected by parked vehicles)  –illustrated with pictures from the Cambridge MA cycle track installed a number of years ago — a reader inquired for more details on how the track segments begin and end.

Ever mindful of faithful readers, here are two ends, alpha and omega:

And just for completeness, the middle:

the lane configuation is the same on the other side of the street, which in addition has curbside parking