David Levinson, a professor of Transportation Engineering in the University of Minnesota’s Department of Civil, Environmental and Geo-engineering, says St. Paul had plenty of time to perfect Green Line traffic signals during six months of test trips.
He suspects the decision not to give the Green Line nearly as much priority at traffic signals as the Blue Line is mostly political. When the Blue Line debuted in 2004, cars queued up for lengthy wait times on Minneapolis cross streets. City engineers in St. Paul feared a repeat.
“I think the city could do more,” Levinson said. “I think the city knew about this for a very long time. I think the city was scared of the very long signal times on Hiawatha Avenue. … They were reluctant to give as much priority.”
Kari Spreeman, a spokeswoman with St. Paul Public Works, said the city is committed to making sure bicyclists and pedestrians can cross the avenue, cars can make left turns, and the light rail can go by. It’s a lot to balance.
“We have a team of traffic engineers working on the system every day and are continuing to work closely with Metro Transit to tweak the system,” Spreeman said. “Our goal is the same as it has been from the beginning — to strike a balance.”
Greg Hull, an assistant vice president with the American Public Transportation Association, said he’s seen other cities wade through similar questions about how to balance major transit investments with competing traffic demands.
“The challenges you’re facing in Minneapolis-St. Paul are not unusual for what you’ll find in most cities,” Hull said. “They become political decisions, and it becomes a matter of local jurisdictions needing to determine what’s in their best interest.”
Some transit engineers say the conflicts between cross-traffic and public transit aren’t always as significant as they are perceived to be. A 2003 study based in Fairfax County, northern Virginia, found that giving buses priority at intersections through extended green lights improved their reliability without significant impacts on traffic at cross-streets. In fact, the traffic queue on the side streets increased by one vehicle.
“It’s important to recognize there’s a trade-off,” Levinson said. “That said, there’s going to be a lot more people in a train than in a car at any time, so the trade-off should favor the train.”
Nate Khaliq, a former firefighter and neighborhood activist who lives in the Summit-University neighborhood, said he was surprised that the train doesn’t already get priority at traffic lights.
“I would have thought they’d have all this stuff together, when you put $1 billion into a public transportation project,” Khaliq said. “It certainly wouldn’t bother me to wait a little longer at stop lights.”
Comment: I did the interview over the phone while riding on the Green Line. We (the east-bound train, with me aboard) made the lights until we entered St. Paul. We were stopped at a Red Light at Berry Avenue, a street with very little traffic, the first light wholly inside St. Paul.
Publication date: September 2014 Source:Transportation Research Part F: Traffic Psychology and Behaviour, Volume 26, Part A
Author(s): Evelyne St-Louis , Kevin Manaugh , Dea van Lierop , Ahmed El-Geneidy (preprint)
Abstract: Understanding how levels of satisfaction differ across transportation modes can be helpful to encourage the use of active as well as public modes of transportation over the use of the automobile. This study uses a large-scale travel survey to compare commuter satisfaction across six modes of transportation (walking, bicycle, automobile, bus, metro, commuter train) and investigates how the determinants of commuter satisfaction differ across modes. The framework guiding this research assumes that external and internal factors influence satisfaction: personal, social, and attitudinal variables must be considered in addition to objective trip characteristics. Using ordinary least square regression technique, we develop six mode-specific models of trip satisfaction that include the same independent variables (trip and travel characteristics, personal characteristics, and travel and mode preferences). We find that pedestrians, train commuters and cyclists are significantly more satisfied than drivers, metro and bus users. We also establish that determinants of satisfaction vary considerably by mode, with modes that are more affected by external factors generally displaying lower levels of satisfaction. Mode preference (need/desire to use other modes) affects satisfaction, particularly for transit users. Perceptions that the commute has value other than arriving at a destination significantly increases satisfaction for all modes. Findings from this study provide a better understanding of determinants of trip satisfaction to transport professionals who are interested in this topic and working on increasing satisfaction among different mode users.
Jim Pethokoukis at AEI writes about what Republican transportation policy should look like. I am glad my ideas are being embraced by both AEI and the Obama administration.
University of Minnesota Transportation expert and must-follow blogger David Levinson was recently asked what he would do to help low-income residents if given $1 billion to spend. Now the context here is the opening of $1 billion light-rail line between downtown Minneapolis and St. Paul. Levinson:
Why are buses treated as second-class transportation options? One reason, this Next City story suggests, is that middle-class (and above) citizens are kind of snooty about buses. They view them as transportation purely for poor people. “Only losers ride the bus.” Of course, this is a cultural and financial choice. Buses could be cooler and, more importantly, provide better service. And one group they could provide better services for is … lower-income people who have limited commuting options. …
Transportation policies and plans encourage non-motorized transportation and the establishment of performance measures to assess progress towards multi-modal system goals. Challenges in fostering walking and bicycling include the lack of data for measuring rates of walking and bicycling over time and differences in pedestrians and bicyclists and the trips they make. This paper analyzes travel behavior inventories conducted by the Metropolitan Council in the Minneapolis-St. Paul Metropolitan Area in 2001 and 2010 to illuminate differences walking and bicycling over time and illustrate the implications for performance measurement. We focus on the who, what, where, when, and why of non-motorized transportation: who pedestrians and bicyclists are, where they go and why, when they travel, and what factors are associated with the trips they make. Measured by summer mode share, walking and bicycling both increased during the decade, but the differences between the modes overshadow their similarities. Using descriptive statistics, hypothesis testing, and multinomial logistic models, we show that walkers are different than bicyclists, that walking trips are shorter and made for different purposes, that walking and bicycling trips differ seasonally, and that different factors are associated with the likelihoods of walking or bicycling. While the increase in mode share was greater for walking than bicycling, the percentage increase relative to 2001 share was greater for bicycling than walking. Both walking and bicycling remain mainly urban transportation options. Older age reduces the likelihood of biking trips more than walking trips, and biking remains gendered while walking is not. These differences call into question the common practice of treating nonmotorized transportation as a single mode. Managers can use these results to develop performance measures for tracking progress towards system goals in a way that addresses the unique and different needs of pedestrians and bicyclists.
Excelsior, Minnesota is home to Minnesota’s second operating streetcar line (part of the Minnesota Streetcar Museum). Being good transportationists, we visited a few weeks ago. Excelsior is legally a city, though really a town, with about 2400 people. Excelsior is coated about 20 miles southwest of Minneapolis (map), connected directly by Mn 7, and more circuitously by Excelsior Boulevard (County 3). Though the town’s population is small, it possesses a main street (Water Street) that serves a larger market area, though the businesses are clearly appealing to those with some accumulated capital (flickr).
The area was developed in part by Twin City Rapid Transit, back in the day, when it extended its line here as a terminus, aiming for both weekday and weekend service, the latter to try to attract reverse direction (outbound) weekend flows for people seeking a summer holiday in this lakeside town. Lake Minnetonka is a huge attraction, and TCRT constructed Big Island Amusement park nearby, connected by TCRT ferry. Unfortunately for Tom Lowry and company, this venture only lasted from 1906-1911. Another entrepreneur, Fred Pearce, was more successful on a mainland site, as the Excelsior Amusement Park lasted from 1925-1973, before the owners migrated southward to Valleyfair.
Today Water Street retains the common features of late 19th/early 20th century streetcar nodes and main streets, a good frontage of retail activity for several blocks. There is on-street parking, with far more parking around the back. Water Street naturally enough leads to the Lake, which is pleasant to look at, and I am sure pleasant to boat on. (I don’t really have much to say about maritime transportation). It is well-maintained and fixed up, with the all important streetlights, but more importantly, fully occupied, which is more than can be said for some main streets in Greater Minnesota. The main downside is that the developed area is fairly small, which is a shame, for there is far more retail activity in and around Lake Minnetonka in much less pleasant designs.
The Streetcar Museum (which is basically a trolley ride plus the shops) is well worth the $2 admission. My favorite part are the ads on the interior of the streetcar (among them, promoting Ludefisk).
High Occupancy/Toll (HOT) Lanes typically charge a varying to single occupant vehicles (SOVs), with the toll increasing during more congested periods. The toll is usually tied to time of day or to the density of vehicles in the HOT lane. The purpose of raising the toll with congestion is to discourage demand enough to maintain a high level of service (LOS) in the HOT lane. Janson and Levinson (2014) demonstrated that the HOT toll may act as a signal of downstream congestion (in both general purpose (GP) and HOT lanes), causing an increase in demand for the HOT lane, at least at lower prices. This paper builds off that research and explores alternative HOT lane pricing strategies, including the use of GP density as a factor in price to more accurately reflect the value of the HOT lane. In addition, the paper explores the potential effect these strategies would have on the HOT lane vehicle share through a partial equilibrium analysis. This analysis demonstrates the change in demand elasticity with price, showing the point at which drivers switch from a positive to negative elasticity.
A producer for Real Money with Ali Velshi sent along five questions that Velshi might have asked during the interview about the Green Line. My talking points are below. Clearly this is too complicated for a three and a half minute interview.
1. So we often talk about investment in public transit as way to stimulate private development, make certain regions more attractive for businesses and residents. But is there a growing awareness that these projects don’t always improve life for all income classes? That they spur on gentrification can actually push out lower-income, working class residents?
Certainly gentrification is possible, however the case of the Green Line won’t see too much gentrification at first because there is so much vacant land in the corridor: parking lots and abandoned car dealerships, that can be redeveloped. Once the vacant land is consumed, this becomes a much more significant issue. The City and Metropolitan Council have a number of programs that have subsidized “affordable” housing in the corridor – most projects along the corridor in St. Paul have some public financial support.
It is important to remember that in Minnesota people don’t have a property right in low rents, and rent control is a bad idea that discourages investment.
2. As we just saw in the piece, the Twin Cities implemented a multi-faceted plan to help low-income residents and businesses along the Green Line. But there’s already been a hike in property taxes and 25% increase in median rental rates along the Green Line corridor. Did the city do enough?
Any accessibility increase will result in appreciations in property values. However, average prices have risen in the corridor in large part to the new housing (that is, new housing is more expensive (and nicer) on average than existing housing, pulling up average rents), along with improvements in the economy in general.
New housing in the city will keep prices lower than they otherwise would have been in the absence of new housing, as it pushes out the supply curve. And if there were more housing supply added here, near rail stations, there is less elsewhere in the region than there would have been in the absence of the Green Line.
3. You worked before in transportation planning – if you had a billion dollars and were really setting out to help low-income residents, how would you have spent the money?
I would improve the bus system. Buses are more adaptable and flexible than rail. This matters because land use patterns change over time, and this kind of flexibility allows the transportation services to follow their customers. Buses also have the advantage that they can “free ride” on existing roads, and so have much lower infrastructure costs. In just about all US cities buses serve more riders than rail system do, yet rail attracts the bulk of funding.
There are a number of improvements that can be made to buses, arterial Bus Rapid Transit systems provide higher quality, higher frequency, more reliable, and faster service, and that network should be built out and extended.
To be clear, the Green Line is the best rail project in the Twin Cities region, connecting two existing downtowns and the University along a relatively high-density urban corridor. The remaining extensions are more problematic, serving primarily suburban commuters.
Certainly for transit users, some investment is better than no investment, but that doesn’t mean we should support any investment that comes down the pike, instead we should try to design systems that best serve existing good transit markets – usually areas built before 1930, where the existing land uses are conducive to transit, rather than hoping to transform suburban green fields subject to the vagaries of speculative development.
4. If expanding bus systems would provide the most benefit for less money, why are so many cities focusing on building light rail systems? We’ve seen in cities like Portland, which has spent some $4 billion on light rail, street car, or commuter rail lines, spending on bus systems has actually dropped some 10 percent…
The people making and lobbying for rail investment decisions are generally not transit riders. They live in the suburbs and work downtown in offices and their mental model is everyone else does as well. Most trips are not work trips. Most people don’t work. Most people who work, don’t work downtown. Most people who work don’t work in conventional office buildings. The decision-makers can’t imagine themselves riding on local buses (for a variety of reasons) and so design services for people like themselves rather than people who already use transit.
5. Did the Twin Cities really need to build a light rail? And can it really have the dramatic economic effects across all income levels that city officials hope for?
“Need” is a strong word. Given the federal government pays for half of transit capital investments, it was locally rational to build the Green Line. It serves users on the corridor better than previous buses because it has a higher frequency, but that is a property of the frequency, not a property of it being a train. It is important to note that much of the local funding for the lines comes from local sales taxes (which are regressive, that is the poor pay a greater share of their income for this than the wealthy), as well as a motor vehicle sales tax.
Suppose you have a train moving along (parallel to) an East-West (EW) signalized arterial.
Case 1: If the signals are pre-timed, and the timings are known in advance, the train should never have to stop for the signals (aside from emergency signal pre-emptions and other edge cases). Instead, the train should be able to adjust its speed so that it doesn’t have to stop. It might go at an average speed of say 10, 20, 30, or 40 MPH in order to ensure it hits a green light or better a green wave from whenever it departs a station. The train driver can be apprised of the optimal time to leave the previous (upstream) station, and the speed to travel to hit “green” lights.
Green waves have been around since the 1920s (See Henry Barnes’s autobiography: The Man with the Red and Green Eyes. Dutton. 1965. OCLC522406). Static signs to tell travelers the speed of the green wave has been in standard use in some places (e.g. Connecticut Avenue in Washington, DC) for almost as long. Dynamic real-time signs which tell travelers what speed to adjust to to make the green wave has been recently patented and tested in simulation for automobiles: Always Green Traffic Control. The time is ripe for some carefully controlled field experimentation.
Still, pre-timing with information certainly doesn’t guarantee the fastest speed possible for the train, but it does guarantee no stops except at stations, which is good for a variety of reasons, including both travel time (avoid acceleration/deceleration loss), traveler comfort, energy use, and train wear and tear.
Case 2: If the signals are actuated, that is, their phase and perhaps cycle timings depend on traffic levels, and traffic “actuates” the signal, usually through an in-ground loop detector, transit signal priority from a fixed upstream distance should be sufficient to ensure the train doesn’t stop at a “red” light. The traffic light controller would know that a train was coming, and either keep the lights in the direction of the train green (if they are green), or change them to green and hold them, if it is currently red and the green is coming up. The train, knowing when the green will be on, should be able to adjust its speed (faster or slower) to make the green without stopping.
The distance that trains can currently notify a downstream signal controller is when they depart the upstream station, which is up to 1/2 mile or so (the spacing between stations). 1/2 mile at 30 mph takes 1 minute. With a cycle time of 2 minutes, and at least half the green time (1 minute) for the signalized arterial, a green can be guaranteed. If the light is currently red, it will be green within a minute. If it is currently green, it can be kept green for up to a minute. The worst case is it was just about to turn red and instead the green is extended for an additional minute. Alternatively, if it is currently green, a shorter than usual red phase can be inserted to clear the crossing traffic, before the light is turned back to green.
For traffic signals less than 1/2 mile downstream (say 1/4 mile) the warning time is only 30 seconds at 30 MPH. The same logic applies, but it is potentially more problematic as there is less lead time to adjust the timings, so the phase shortenings might be more severe. On the other hand, if more than 50% of the green time goes to the EW movement (say 75%) you aren’t really any worse off.
At 1/10 of a mile the warning time is less, but train departure from the station should be able to be coordinated with the light directly.
Case 3: But let’s say your traffic engineers are incapable of making this work. Should the train and its passengers suffer? This is where traffic signal pre-emption comes in. Most widely used for emergency vehicles, this potentially changes the sequence of phases, so maybe a phase is dropped (it doesn’t occur within the cycle, or within the usual place in the cycle).
This system does ensure that the vehicle requesting the pre-emption gets a green light as quickly as possible (safely turning the conflicting movements to a red phase) and thus can drive at as high a speed as possible. While trains should not need to stop at traffic lights with priority and speed adjustments, with pre-emption, they neither need to stop nor adjust their speed.
What could go wrong?
Pedestrians. Thus far we have been talking about a system with cars and trains. Pedestrians too can actuate signals, though “beg buttons“. These may function similar to vehicle actuators, in telling the traffic signal there is someone who wants to cross. The difficulty for priority or pre-emption is that a pedestrian phase may need to be longer since pedestrians take longer to cross the street than a vehicle does, especially if the street is very wide. So a pedestrian actuator may also extend the green time, in addition to calling for green time. This makes it more difficult to quickly change lights from red to green, since for safety reasons you can’t strand a pedestrian. This makes the ability to adjust train speeds in concert with the traffic signals more important.
Emergency vehicles. Emergency vehicle on emergency vehicle crashes are a known problem, and pre-emption may make it worse as firetrucks approaching a scene from two directions may both demand a green light, but only one gets it. The driver of one vehicle, not realizing he didn’t get the green (especially if he had the green as he was approaching), fails to yield. There are solutions to these problems.
Any of this will likely lead to additional delays for conflicting vehicle movements (cars making left turns or North-South traffic crossing our East-West arterial). With priority, this may even lead to extra delay for some vehicles on the parallel arterial who have been given a short green so the conflicting traffic can also get a short green before the EW arterial returns to green.
However the train usually has more people on it than are queued up at the other directions, so total *person* delay will generally be reduced.
For a variety of reasons, delay is bad (unless your goal is punishing drivers and air-breathers), we want to minimize total person time (or weighted total person time – recognizing long weights are more onerous than short weights) in the system (because time is money), and minimize pollution outcomes as well.
In short, the Green Line not getting green lights on University Avenue is a solvable problem. It should have been solved already. It eventually will be solved.
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