It’s Friday afternoon, and people are waiting in front of MIT’s Infinite Corridor on Massachusetts Avenue for the northbound No. 1 bus.
According to the schedule on the MBTA website, buses on the No. 1 line toward Harvard Square are supposed to stop at 3:06, 3:18, and 3:20 p.m.
But on this day, just after 3 p.m., two No. 1s arrive. Five minutes later, another one arrives.
Then the flow of buses stops. At 3:30, retired researcher Ray Ausrotas, 71, sits on a bench at the stop, watching the traffic make its way over the bridge from Boston, checking if he can spot a bus.
“They seem to come in bunches,” he said. “It’s probably impossible for them to come on a regular schedule.”
Austoras is soon joined by French astronomer Cecilia Cecconelli, 48, who is working at the Smithsonian Astrophysical Observatory at Harvard, and her two daughters.
“They are irregular, they don’t come often enough, and I’m talking about rush hour,” Cecconelli said of the No. 1 buses. “We live in France. We are used to a good public transportation system.”
The next No. 1 bus arrives at about 3:40, and it’s so crowded that most of the passengers who board at the MIT stop have to stand.
The No. 1, which runs, mostly on Mass. Ave., between Harvard Square in Cambridge and Dudley Square in Roxbury, hits its 40th anniversary this year, but nobody is celebrating the milestone.
It’s one of the lines that generates the most complaints in the MBTA system, said spokeswoman Lydia Rivera. The No. 1 racked up the highest number of complaints of any line in May, 42, and the second highest in June, 34, she said. In the latter month, there were 49 complaints about the No. 66 route, which also runs from Harvard to Dudley squares, but through Brookline.
Conversations with No. 1 bus riders reveal that the most common complaint is that buses often travel in bunches, creating long gaps in service and rendering schedules entirely unreliable.
MIT student Cassandra Gibbs, 20, says she gets on the bus mostly for the air conditioning. Because she never knows when the bus will show up, Gibbs says, walking is usually faster than taking it.
“I remember once I was sitting in front of the Hynes/ICA waiting for a bus to go across the river,” she said, “and I was waiting for maybe 45 minutes and there were six No. 1 buses going from Cambridge to Boston. I counted them because I was so upset.” She added that she often sees two or sometimes three buses right after each other. “It’s like a caravan of No. 1s. Maybe it’s the traffic, but it doesn’t account for the fact that there are three buses right after each other.”
Financial analyst Nalini Babooram, 26, of Boston, who takes the No. 1 bus to work in Cambridge each morning, had a similar complaint, and said she would be very interested to hear the MBTA’s explanation.
“I’d like to know what they say, seriously,” she said.
What the MBTA says, through James Folk, its transporation chief, is that the T supervises departures at the two endpoints of the route – Harvard and Dudley squares – daily, but does not monitor the line regularly anywhere in its middle.
“There’s a lot of traffic lights and a lot of construction on Mass. Ave,” Folk said. “It’s a difficult route because of the length of the route.”
A more elaborate analysis comes from Yossi Sheffi, an MIT engineering professor who is also director of the MIT Center for Transportation and Logistics. According to Sheffi, a bus that for whatever reason is running a few minutes late will tend to get more and more off-schedule as it progresses along a route.
This happens because when it arrives at a stop late, it will have to pick up more passengers, who will take more time to board. At the following stop, the bus will be even later and have even more people to pick up. Meanwhile, the bus behind it will have fewer people to pick up and will accelerate, allowing it to catch up.
Any system that moves under random conditions will experience bunching, Sheffi said. Random conditions that contribute to the bunching of buses include traffic congestion, stoplights, and the number of passengers at a stop.
“The traffic lights are just one aspect of randomness, because you don’t know if you’re going to hit green or red. It’s one aspect of uncertainty, it’s the uncertainty that creates the bunching,” said Sheffi. “The longer the route is, the more pronounced this effect is, and the lack of any control mechanism exacerbates it.”
An MBTA official in the middle of the route who could hold up a bus if it is running too close behind another could prevent bunching, Sheffi said. He said other control mechanisms could also work, such as a global positioning system (GPS) on buses connected to a dispatcher’s screen, allowing him or her to see the locations of other buses on the route and to communicate with drivers.
A solution may not be as far off as it may seem. Already, all MBTA buses have a GPS on them, Rivera said, but the system is used to announce stops for passengers, not to prevent buses from bunching.
Only the Silver Line, as well as the No. 39 and the 32 bus lines, have a GPS that allows dispatchers to see the locations of buses and communicate with drivers, but Folk said the MBTA is running a pilot program to implement a GPS-based dispatch system on all routes.
“Right now, the pilot program is running well. We’re hoping by next spring it will be fully operational,” he said, adding that the system might be installed even sooner on the No. 1 route, possibly as soon as Jan. 1. He said he “can’t commit to that because it’s a pilot program.”
Sheffi said a control system to prevent bunching doesn’t have to use a GPS, and the GPS by itself isn’t going to solve the problem. Taxis, for example, simply use voice communication when a dispatcher asks for a driver’s location, he said.
For now, MBTA customers will just have to keep complaining – which is exactly what library assistant Richard Pendleton, 64, has been doing. Pendleton, who volunteers at the US China Peoples Friendship Association in Central Square on Friday and Saturday nights, was so dissatisfied with the service that he came to a recent MBTA public meeting in Cambridge with a handout on which he chronicled how long he waited for the bus and how many passed him going the other way. On one night, he said, he waited near Cambridge City Hall for 52 minutes, or until 1:02 a.m., for a bus to Boston, while four passed the other way between 12:50 and 12:55 a.m. By the time he arrived at his Newbury Street stop, though, there was another No. 1 bus just a block behind.
“Clearly there is a problem and something needs to be done,” Pendleton said. “There is no need for three or four buses to move in the same direction at the same time and there are gaps traveling in the other direction. The schedule is lopsided.”