Public transit in Boston is already choked at rush hour, and badly in need of repairs (including complete fleet replacements for two subway lines, now scheduled to start in a couple of years) -- witness the total breakdowns last winter, which had some lines out of service for weeks.

And witness the repercussions. On the third day of the crisis, the Red and Orange lines were out, and a lot of people who normally came on them, drove instead. The result was that Cambridge was utterly crippled with traffic. On my way back from Kendall to Medford, I walked, and I got home earlier than anyone I know.