MassDOT just released an in-depth study of traffic congestion in Massachusetts. The study quantifies the increasing unreliability of driving as a result of congestion. While the report offers no quick fixes, it adds urgency to many ongoing projects and discussions.
The real issue is unreliability. Average commute times measured by the census bureau drifted up by 2.5 minutes in the Boston area between 2008 and 2017. That is an annoyance.
What is unacceptable, is that every week or two, when something goes wrong, the trip can take twice as long. That means that people have to plan for the possibility of longer trip times and need to leave much earlier. For example, the trip from Burlington to Kendall Square via Route 2 most commonly takes about 30 minutes, but on 1 in 10 days takes over 56 minutes and can take up to 90 minutes.
Route 2 eastbound to Alewife emerges as one of the 5 most severely congested route segments in the state, with travel times at rush hour almost 4 times longer than free flow travel times. Fresh Pond Parkway, continuing Route 2 through Alewife to the Charles is one of the most consistently congested segments in the state — it is congested for 14 hours out of the average day.
The available data do not include driving travel times on local roads, but congestion on local roads is reflected in planned speeds for MBTA buses which have declined from 12.7 miles per hour in 2009 to 11.5 miles per hour currently.
There are a few good news items. The trip time of the 501 bus from Brighton to Boston has actually dropped a little with the introduction of automatic tolling on the MassPike. The median trip time is now running just over 35 minutes. However, 10% of the time the trip takes over 45 minutes.
The study highlights the improvements for the 71 and 73 buses due to the new bus lane on Mount Auburn Street between Belmont Street and Mount Auburn hospital. Median trip times on that stretch are down by 3 minutes. Bus reliability has improved even more, with the 90th percentile trip-time dropping 5 minutes.
The study finds that the fundamental cause of congestion is prosperity. Rising population and employment have crowded the roadways, especially in the Boston area. High housing prices close to Boston push people further and further out, putting more cars on the major inbound routes.
As to solutions, the study is realistic. It re-emphasizes the importance of a number of long-term projects that are already under way, including increasing MBTA capacity and ridership.
For me, the most sobering chart in the report compares the traffic volume on major commuter corridors with the commuter rail lines that parallel them. On the major corridors, the drivers outnumber train riders by 5 to 10 fold. On the one hand, these data highlight the availability of more potential train riders. On the other hand, given parking and other constraints, the work of the Rail Vision Study suggests that it will be difficult to raise commuter rail ridership into Boston by much more than 50%. Ridership increases of this hopeful scale would mean relatively little reduction in vehicular volume, given the expectation of continued trip increases.
These data suggest an eventual hard limit on central Boston employment growth unless more housing can be accommodated within the core. And, of course, housing development is already generating local concerns about crowding. The report recommends that, in addition to striving to reduce Boston congestion, we need to encourage growth in less congested gateway cities.
The report does discuss the concept of congestion pricing. It concludes that we cannot meaningfully or fairly introduce congestion pricing using the toll structures now in operation on the MassPike and regional bridges and tunnels. But it does cautiously open the conversation about the possibility of new tolling locations, preferring the approach of tolling only added “hot” lanes as opposed to tolling everyone. We will have much more discussion about congestion pricing in the months to come.