You’re on a bus or a train that is a little behind schedule. If only the light ahead would stay green for just a big longer, the operator could make it through and save some time. When it does, is it luck or technology?
Not to downplay luck, but on light rail trains and certain high-ridership Metro Transit bus routes, computer-guided transponders in the cab might have called ahead and asked for a “green extension” to let the vehicles glide on through. Such “transit signal priority” (TSP) is already used to keep some transit vehicles on time and, when combined with other ideas, make the trip for riders a bit faster and make the schedule more reliable.
Now a task force ordered by the Minnesota Legislature is asking Metro Transit, state and local governments and passenger advocates to work together to make these changes more common. The Transit Signal Priority System Planning working group is looking at signals as well as bus stop locations, bus stop spacing, bus lanes and curb extensions.
Each might shave just seconds off a trip. But combined, they can save several minutes, which can matter when riders make decisions about cars or transit.
“Something I hear really often is that slow travel time is a common barrier for people,” said Julie Johnson, a community organizer for Move Minnesota, a transit advocacy organization. “It hinders transit ridership.” Some riders who are transit dependent for work, school or health care can’t get where they need to go because “our buses are so slow.”
Johnson, therefore, is a big advocate for transit signal priority and wants it used at as many intersections as possible. Combined with bus lanes on high-frequency routes, they could save up to 20% in travel times. For a frequent transit user, that’s 40 hours a year and 780,000 hours of time for all riders system wide, she said.
“We’re really excited that this working group is getting going and we think transit signal priority is going to be the way to speed up the whole system,” said Johnson, who is a member. “It is, system wide, more affordable and faster to implement than some of the other ways. It is a very promising solution.”
“The main intervention we’re trying to do here is increase both speed and reliability,” said Eric Lind, a working group member and the director of the Accessibility Observatory at the University of Minnesota’s Center for Transportation Studies. While there are many reasons for delays – traffic, for example – one factor that can be affected is time spent at signals. While 30 seconds might seem trivial, “thinking about the people waiting at this delay makes it more significant. You’re impacting a lot of people with those 30 seconds,” he said.
“You’re trying to coordinate those small improvements to get a big improvement,” Lind said.
But it’s not all about speed. Making sure buses and trains arrive at stops and stations when the schedule says they will is the primary reason for signal priority and other interventions. If the bus or train is ahead of schedule, it is OK, if not better, to miss the light. Transit Signal Priority systems are sophisticated enough to know that and choose to not extend that green light coming up.
“We would like to have shorter trips from A to B but we also want to reliably meet those travel times. It’s what we call on-time performance,” said Adam Harrington, the director of service development for Metro Transit who is coordinating the working group
A route with an average trip time of 10 minutes but a range of times, say from eight minutes to 15 minutes, would have a low on-time performance, he said. If there are methods to help keep those trip times uniform using TSP and other strategies, that route might be a candidate for an engineering intervention.
Is it the traffic signal or do we have too many bus stops and you have to get in and out of traffic more often?” Harrington said. So far, Metro Transit has coordinated with the state and local governments to equip 146 intersections with signal prioritization systems. Dedicated bus lanes are also being tried, such as was placed on Hennepin Avenue in Uptown. While the trip times didn’t change much, the reliability of the service increased greatly, he said.
Lind said reliability of schedule is most important to a transit system and riders.
“But if you get reliability by slowing the schedule, then that doesn’t make for happy customers either,” Lind said. “The main advantage of transit signal priority is getting better reliability, squeezing those worst trips back toward your average. That’s what it can help you do, get rid of the worst delays.”
Metro Transit hasn’t been waiting for the working group to act. The Speed and Reliability program began in 2018 with a goal of using lots of different ideas to reduce what transit planners sometimes call “dwell time.” That’s when a vehicle is stopped with passengers loaded but isn’t moving, either because it is still at the stop or is stopped on the road.
Techniques include bus lanes like those on Hennepin Avenue in Minneapolis’ Uptown and on 7th Street downtown, eliminating stops used by only a few passengers and using transit signal priority at congested intersections on busy routes. Putting the stop or station after the light can make a big difference in transit times. An operator can get through the light and then stop. If there is a lot of traffic, the light behind them can provide a break that allows the bus to get back into traffic. Fewer stops, a rationale behind cutting some low-use bus stops, also saves time.
The so-called Better Bus Routes project has been used on 2, 3, 22 and 63 with Route 17 added this year and 4, 61 and 11 in the near future.
If Metro Transit is already moving ahead on certain routes to make changes on, why have a working group look at the same issue?
“It may be that there is validation of the routes we already planned to work on, it may be that we prioritize different routes to happen before others, and that’s fine,” Harrington said.
Routes that are slated for future conversion to bus rapid transit, even though they meet the criteria of high-frequency and high-use, will likely not be considered for these changes. That’s because BRT already employs many of them – along with ticketing at the platform, using both doors to board and exit buses and curb extensions so vehicles stay in the traffic lane while passengers board. Those are routes like bus route 21 that will become the B Line along Lake Street and Marshall Avenue and bus route 6 that will become the E Line between the University of Minnesota and Southdale Mall using Hennepin Avenue.
As with anything involving the confluence of cars and buses and trains and pedestrians, it’s complicated. Transit planners say it isn’t as easy as turning the lights along a light rail path or a high-capacity bus route green when they approach. Cross streets have their own needs, and often their own bus routes. Pedestrians need time to safely cross so a light cycle can’t be interrupted when they’re halfway across just because a bus or train is coming.
“Having enough time for a pedestrian to cross a street is an accessibility issue and signals are timed and constrained by that,” Lind said. “Even a busy main transit route and a cross street and it feels like the light is taking a long time and there’s not a lot of activity, some of that is we want to make sure any pedestrians who are there have enough time to get across the street. That can limit how much time is given to a transit vehicle.
“You can’t optimize signal progression in all directions simultaneously,” Lind said. “That might sound silly but sometimes people don’t go to that level.”
Said Harrington: “There are competing demands at every intersection. Imagine in downtown Minneapolis where the bus side of the organization says we really need an advantage at Nicollet to get through everything faster. We also want to make sure the Green and Blue lines on 5th get east and west faster. Which side is going to win that one?”
So far, one meeting has been held of the group that includes staff from Metro Transit, the state Department of Transportation, Minneapolis, St. Paul, Hennepin County, Ramsey County, someone from a city that is served by one of the other regional transit agencies, Move Minnesota and the Center for Transportation Studies at the University of Minnesota.
The reason for having multiple agencies is that nearly everything being looked at steps onto the turf of multiple governments. Metro Transit owns the buses and trains but it doesn’t own the stop lights or the sidewalks where stations and stops sit. Highways are the domain of MNDOT but many pass through cities. The same is true of county routes.
The legislation “does provide a reason and a motivation to get together a group of people who maybe would be hard to get together otherwise,” Lind said.
According to the omnibus transportation bill passed in May, the Met Council must provide a report to the Legislature on next steps by Feb. 15.