Most motorists did not 'ditch the drive' during Sumner Tunnel closure

State transportation officials issued stark warnings in the months leading up to a Sumner Tunnel closure: traffic will be a mess, so motorists should "ditch the drive" whenever possible.

Most people did not heed that advice.

About three-quarters of motorists who typically used the Sumner Tunnel continued to travel by car while the major thoroughfare was shuttered, choosing different congested roadways rather than opting for public transit, according to new data released by the MBTA.

Roughly 40,000 vehicles typically drove through the 89-year-old tunnel per day before it shut down for eight continuous weeks in July and August. During the closure, 77% of those trips continued in cars, split almost evenly between the Ted Williams Tunnel, the Tobin Bridge and other roadways.

"People are fickle, and trying to get them to change is hard," said Lynsey Heffernan, the MBTA's assistant general manager for policy and strategic planning, at a board meeting on Tuesday. "We know service matters, we know communication matters a lot, and the mitigations, I think, is an open question about how much did that help us."

Close to 15% of drivers "disappear[ed] out of the measurable roadway network," said MBTA senior policy analyst Martha Koch. Those people either opted against taking trips they normally would have, or they were part of a typical reduction in travel in July and August.

Only about one in 10 Sumner Tunnel drivers changed their commute in that span to rely on the MBTA, which has been marred in recent years by a steady stream of service disruptions.

The impacts on MBTA ridership as a result were mixed.

On weekdays, Orange Line ridership for State Street and points north grew about 4%, while the Blue Line — which ran free of fares for the entirety of the shutdown — saw about 7% more passengers.

"That is significantly lower than we thought it would be," Heffernan said about weekday Blue Line ridership. "When we've looked at other free fare options that we've had — for instance, on the [Route] 28, we would see growth of 20%. So 7% is low."

But on weekends, the ridership gains were "pretty significant," Heffernan said. The Blue Line gained about 13% more riders, Orange Line ridership jumped 23% and crowds on the Newburyport/Rockport Line swelled 41%.

Officials are still unpacking the data and trying to figure out why traditional Sumner Tunnel drivers were more willing to hop on the T on the weekend than during the week.

"That was surprising to us, and so [it's] notable to think about and think about why is it that, maybe for your traditional trips, we weren't as much of an option as we hoped for," Heffernan said.

Public transit options that served areas affected by the Sumner Tunnel closure, like East Boston and the North Shore, saw more significant ridership increases than the rest of the T. The East Boston ferry — which MBTA officials recently decided to keep running until Nov. 30 due to its popularity — added about 350 passengers per typical weekday, a growth of 72%, MBTA data show.

In addition to eliminating Blue Line fares, the MBTA also increased train trip frequency on the Orange and Blue Lines during the shutdown. That boost combined with the tunnel closure made the subway a far more competitive option, according to MBTA data.

During the final weekdays that the tunnel was closed, it took about 28 minutes to drive from Maverick Square in East Boston to Downtown Crossing starting at 8 a.m. Roughly the same trip using the Blue Line — which goes to nearby stops but not Downtown Crossing itself — took about 14 minutes, or half as long, the data show.

But as soon as the tunnel reopened, the driving time to get from Maverick to Downtown Crossing plummeted to be roughly equal with the length of a subway trip.

MBTA officials projected early in the summer the agency would lose about $6.1 million in fare revenue by lowering or eliminating costs during the tunnel shutdown.

Although the tunnel reopened to motorists on Sept. 1, the work is not yet complete. Officials plan more weekend closures before the year's end, and another two-month shutdown is on the horizon next summer to allow for repairs on the driving deck.