State Needs to Focus on Getting Drivers to Take the T (or carpool, bike, or walk) as Well As Bridge Repair

Except for the Mass Ave bridge, every bridge in the lower Charles River basin is going to get repaired over the next five years or so. Hopefully, the end result will be structurally sound structures within a transportation system finally able to serve pedestrians, bicyclists, and transit vehicles as well as cars, which will also provide improved access to the region's river bank parklands. However, the construction period will cause a massive reduction in the system’s car-carrying capacity.

We already know, from bitter experience around the country and the world, that building more roads to relieve congestion will only attract more drivers until the new roads are over crowded as well. It seems that, in most transportation systems, if you build it they will come.

But the same "potential capacity causes actual volume" dynamic works in reverse. As shown by much research and Boston’s own Big Dig experience, traffic tends to shrink along with the road system’s carrying capacity – meaning that the fewer roads there are the fewer cars try to use them. The proven reality of this "shrinkage" dynamic is one of the keys to solving many of our region's transportation problems.

But no matter how much traffic shrinks, there will still be a lot of people trying to drive across the Charles River over the next five years. It is vital that state and municipal governments immediately start making it easier for people to switch from single-occupancy vehicles to car pools, or transit, or bikes BEFORE the bridge repair work brings the whole region to a gridlock. Success requires a significant and immediate expansion of commuter rail and bus service -- both of which are currently hostage to the MBTA's funding crisis.

Fortunately, the "if you build it, they will come" dynamic also works for bike lanes and cycle tracks. So while the primary mode shift of commuters away from Single Occupancy Vehicles (SOV) will have to be into trains and buses, it is vital that the Department of Conservation and Recreation (DCR) and Mass Highway Department (MHD) aggressively prioritize the inclusion of cycling and walking facilities in their bridge plans, both for the final design of the renovated structures and for the fast-approaching construction period.