If Boston decided to set up a congestion zone, where would we put the boundaries? Boston could easily borrow from the successful models of both Stockholm and London. Stockholm is a city of islands, so it only needs camera gantries along bridges crossing its waterways. On its north side, Boston could replicate Stockholm by placing toll sensors on bridges over the Charles River from Cambridge, Charlestown, and East Boston.
The situation in Boston becomes more complicated to the west and the south, where drivers have myriad land entry points, such as along Soldiers Field Road, Commonwealth Avenue, Route 9, Columbus Avenue, Blue Hill Avenue, or Massachusetts Avenue.

Comments
What about those who MUST DRIVE in and out of Boston--all day--as I used to do when I was a field service technician? What about those who do not live near public transport, or whose working hours--especially on weekends--prohibit the use of public transportation? This is merely another elitist proposal that would have cascades of unintended, damaging consequences for people who can least afford to bear them.
This article is useless. It does nothing to explain the workings of a congestion zone.
For the first time the dysfunctional state of the T led me to give driving in from the North Shore a try. Wow, I expected there to be some congestion but no Blade Runner kind of nightmare scenario could have prepared me for how bad the choking gridlock really is in Boston. For me it became yet another example of how much insanity humans learn to accept as part of their daily lives. The first couple of times of hitting the wall of parking lot gridlock beginning some nine miles outside of the city on 93 was a real shocker: "Wow, these people do this every day, they're nuts!" Over the next few weeks the extent of this insanity became apparent: on my iPhone's traffic alert map app red lines of gridlock spread in every direction around Boston like varicose veins. I learned that these suffocating varicose veins clogged all major arteries going into Boston beginning well before 6 am and didn't subside until well after 9am. In the reverse direction the red veins of gridlock began at around 3:30pm and stayed a bulging red until at least 7pm. I thought of the countless thousands of cars burning oil and spewing out exhaust gases in these endless rivers of gridlock, meandering along at between 5 and 15 mph, with one person sitting in each vehicle. Think about it: we've devised a transport system in which some 4000 pounds of metal and plastic, along with the equivalent of thousands of kilojoules of energy per car, are required to move one person from home to work. A 20-pound bicycle would move that person more quickly! So, this is the height of human ingenuity, of human intelligence! And native Bostonians have since told me that this state of affairs has existed for decades now in Boston. Now knowing how bad things really are in this city, even more baffling than the insanity of this situation is that it's apparently not even an issue to the city's leadership, that's it's simply accepted as a normal part of life in Boston. Knowing this also puts much else in better perspective, like how ludicrous it was to spend $20 billion on something as ridiculous as the Big Dig! Just imagine how much better, in terms of solving *real* problems, that money would have been spent building out a much more extensive state-of-the-art public transportation system! Needless to say I returned to taking the T, it was the better of the two evils...