Friday, July 27, 2012

Conservative traffic studies are radical

I've been writing on the topic of traffic and models for a bit now, and the reason it's on my mind these days is the New Brighton Landing project which is being designed by New Balance. The Planned Development Area materials include an Exhibit E - Transportation Study, which has flagged my attention. New Brighton Landing will be built in three mostly vacant parcels on the edge of Allston and Brighton near Everett Street, on the south side of the Mass Pike. This spot is about half a mile from Allston's Union Square, which also happens to lie on the path to the Mass Pike ramps in Allston.

Union Square is a fairly active neighborhood, with the Jackson-Mann school on one side, the fire station on another, and a diverse set of restaurants, bars and other small shops scattered around the other edges. The key bus routes 57 and 66 connect here with the less frequent 64, making it a transit node. Union Square marks the intersection of Cambridge Street with the end of Brighton Avenue, and the beginning of North Beacon Street.

In an earlier iteration of the plans, there were plans afoot to widen Cambridge Street here from two to four travel lanes, and they were based upon projected volumes generated by the new development. For now, it seems like community input has caused them to shelve those plans, though nothing is certain.


What led them to consider such measures is the projected level-of-service for the intersection, after they applied certain traffic growth factors. The study is founded on the assumption that traffic levels grow 0.5% per year, every year. This assumption is baked into several places, e.g. page 17:

Based on discussion with the BTD, the study team developed Year 2012 traffic volumes for the New Brighton Landing’s transportation analysis by adopting the Year 2007 traffic data from the Lowe’s work and increasing the volumes by an annual growth factor. 
[...] The annual factor of 0.5% was applied to the Year 2007 counts to produce existing condition volumes for weekday a.m. peak hour (8-9 a.m.), weekday p.m. peak hour (5-6 p.m.) and Saturday Midday Peak hour (12:45-1:45 p.m.).

The trouble with this assumption is that regional and national trends have shown a peak in vehicle miles traveled that occurred sometime between 2005-2007, and a reduction ever since. As it happens, MassDOT offers an interactive map interface which can be used to query some of their actual traffic data. So I looked at locations around Union Square and Allston to see what historical data was available. As it happened, four appropriate readings were available, each having entries for 2002 and 2010, in terms of Annual Average Daily Traffic (AADT).



Location20022010Percent Change
Cambridge Street near Linden Street40,00037,797-5.5%
Cambridge Street near Union Square25,40023,971-5.6%
Brighton Avenue near Park Vale Avenue30,20028,547-5.4%
Harvard Avenue near Farrington Avenue17,20016,213-5.7%

It turns out that in the vicinity of Union Square, not only has traffic not increased by 0.5% a year, it has actually decreased by almost 0.7% per year. The following chart sums of the difference between the actual differences in traffic vs what the glib projections would have guessed.

Actual traffic levels decreased from 2002 to 2010.
The difference is nearly 10% of the total for all four and, crucially, straddles the zero line. That the BTD was going to consider roadway expansion in this area, on the basis of projections that were diametrically wrong, is extremely disturbing. The reasons behind the drop in vehicles are not clear. It could be the near depression, and perhaps counts will skyrocket again once prosperity returns. The problem with this hypothesis is that the national trend of downwards VMT was already being noted and written about prior to the financial crash.
While total driving in both rural and urban areas grew between January 1991 and September 2008, rural and urban VMT have been declining since 2004 and 2007, respectively. Amongst these collective driving declines, the nation shifted more of its VMT share to larger capacity, urban roadways.
And, notably, the data collector on the nearby Mass Pike indicates an upward slope over the same years that Union Square has a downward trend. So it seems more likely that there is a serious change in the way we are using these local roads.

The study claims that the New Brighton Landing development will bring additional traffic. They estimate 12,000 vehicle entries and exits a day. Most of that will be for the office space, some for the restaurants and retail, and also for the hotel being planned. The other major draw is the new sports complex, but presumably that will have its peaks at different times. The numbers are based on the Institute of Transportation Engineers' Traffic Generation handbook, which provides pat numbers for everything but the sports complex. While it is standard procedure to use such numbers, it seems wrong to base such estimates on studies generated outside of Boston, and outside of Massachusetts, in a completely different environment. Even worse, without any data, the study assumes that 100% of sports complex related trips will be made by automobile. Page 43:
To be conservative (highest impact), however, all ice rink and track and field facility trips have been assumed to arrive/depart by vehicle.
The chronic problem of traffic overestimation I debunked above is also referred to as a "conservative" approach. But the only "conservative" aspect is that it would lead to the destruction of the environment in the neighborhood. Such overestimation is actually quite radical if it leads to destructive road-widening.

A truly conservative approach would seek to mitigate traffic and preserve the quality of life in the neighborhood. That is why Transportation Demand Management, as deployed in Kendall Square, is likely the best way forward. Luckily, it seems that New Balance is on-board with this approach. They already sponsor Hubway, and are providing the funds for the new Commuter Rail station. They are also pouring a lot of resources into making the development area more friendly to walking, bicycling, and safe driving by fixing the decaying infrastructure and creating new, smaller blocks with street level retail.

Ultimately, I'm really happy about the project, and I'm glad they have decided to invest $500 million into the neighborhood. I just did not want to let the fallacies embedded in the transportation study slip by unnoticed, as they are pervasive problems that will likely need to be corrected in other, future plans as well.

Wednesday, July 25, 2012

Added traffic is not inevitable

The Boston Globe has a nice article by Eric Moskowitz posted today, Car-free commuting push pays off in Kendall Square:
Despite the rapid expansion in and around Kendall Square in the last ­decade — the neighborhood absorbed a 40 percent increase in commercial and institutional space, adding 4.6 million square feet of development — automobile traffic actually dropped on major streets, with vehicle counts falling as much as 14 percent.
Although more commuters are churning in and out of Kendall each day, many more than ever are going by T, bike, car pool, or foot. 
Compare that to quotes from a recent article in The Harvard Crimson, Architect Presents Details of Allston Residential and Retail Project:
When the same land parcel was discussed in 2006, a hockey rink was on the table, but nothing of that size was mentioned this time around. But members of the audience voiced some of the same concerns as six years ago, focusing mostly on parking and safe traffic flow. 
One member of the audience said that parking was hard to find as is and that he was worried it would only get harder after development. The current proposal includes two levels of parking to accommodate consumers and residents. 
Other residents expressed worries about the potential ramifications of putting a large development at an already-complicated intersection. “I think they have a major safety problem with traffic that conceivably could create a lot of traffic problems stretching all the way down North Harvard [Street] and Western [Ave.],” Allston resident Ed A. Kotomori said at the meeting.
Now, it is true that one major difference between North Allston and Kendall Square is that while Kendall has the Red Line, there are only buses running through North Allston: specifically the 66, the 70, and the 86 at this particular site. But there are a lot of similarities too. Not too long ago, Kendall was a largely empty area, like Western Avenue is today. Kendall's development is largely driven by the proximity of MIT. The Allston project is owned and being developed by Harvard University, which intends to make this a center for research. So, the intended demographic picture is pretty similar; and they will be of the younger generation that prefers to walk, bicycle and ride public transportation instead of dealing with the hassles of cars and traffic congestion.

Both Harvard and New Balance, which is peripherally involved, seem to be open to promoting non-car transportation options, and they both certainly have the political weight to see it through. But will Boston work with them, or lag behind? At the last New Brighton Landing meeting, the BTD showed up with a plan to widen Cambridge Street from two lanes of traffic to four, which will make the street leading up to Union Square (Allston) a much more dangerous place than it already is. This plan seems to be an echo of the old, discredited ways of dealing with future traffic projections. But, as the Kendall Square example shows, it is possible to have development and growth without creating more congestion. There is nothing inevitable about it; the transportation choices of the community today will ultimately shape what traffic is like tomorrow. If the community decides to promote wider roads and parking lots, then traffic will increase accordingly. If instead the community decides to promote non-car transportation, then traffic will not increase. It's in our hands.

Wednesday, July 18, 2012

Henny Penny in New Jersey

The sky is falling!
I was in New York last weekend and one of the big stories there was the partial closure of the Alexander Hamilton Bridge -- for much needed repairs -- which handles most of the traffic coming off the George Washington Bridge into New York City and headed east. The media was publishing frenzied articles about the oncoming traffic catastrophe. All the experts and elected officials were wringing their hands in worry.

The Record:
Predictions of hour-long delays and traffic jams extending for more than 5 miles have police in Bergen County towns along Route 95 on the lookout for spillover traffic. While some communities are taking a wait-and-see approach, others say they will stop through-traffic from turning local roads into parking lots.
The New York Post:
Beginning Saturday night, the construction will back up drivers for an average of five miles into New Jersey on three main routes:  
* On I-80, as far west as Hackensack.
* On the New Jersey Turnpike, as far south as the Vince Lombardi Service Area.
* On the Palisades Parkway, as far north as Route 4.
“It’s crazy. You can’t do this to people!” said Paul Constable, 54, of Beacon, a regular GWB user.
Fort Lee Patch:
This summer could be remembered as a traffic hell by the millions of people who travel east over the George Washington Bridge thanks to the closure of a lane on the oft-congested Cross Bronx Expressway from this Friday through Labor Day.
Funny story: it didn't happen. The New York Times:
As of Sunday afternoon, there were no signs of the traffic Armageddon that many predicted when an extensive construction project closed a lane of the Alexander Hamilton Bridge over the Harlem River.
But maybe the baseball game wasn't enough. Monday was the real test to come. NJ.com:
By 7:20 a.m., fears of a gridlocked George Washington Bridge had yet to materialize, with normal delays on the GWB and other Hudson River crossings into New York, said Bob Glantzberg, operations manager for TRANSCOM, the East Coast traffic information clearinghouse. Traffic on those crossings was on par with most Monday mornings, he said. 
Well, maybe everyone was fearing the worst on Monday and avoided the bridge, right? Fort Lee Patch:
For a second consecutive morning, Fort Lee Mayor Mark Sokolich surveyed the area near the George Washington Bridge, and once again he found, as most rush-hour commuters apparently did, that traffic was moving along normally Tuesday with only minimal delays at worst.
The latest excuse from the Very Serious People is that this is a lightly trafficked time of year, and we will have to wait until September for the disaster to begin. My question instead is: Can we hear a representative from the cult of Traffic "Engineering" come down and say that they were wrong? That they really don't understand how these complex systems work? And that using their so-called "modeling" to alarm the public is nothing more than a ploy to game more taxpayer dollars for needless road expansion and concrete pouring that destroys neighborhoods?

Tuesday, July 10, 2012

Why are we shackling our future to crude traffic models?

The Casey Overpass (project)
Potentially good news received: the Casey Arborway design may be reduced by two lanes. The at-grade intersections replace the failing Casey Overpass. Originally, MassDOT planners had pushed for an extra two lanes for the corridor that is being renovated, even though the Arborway on either side is only four lanes.
The “opening year” design, so called because it is aimed at accommodating 2016 levels of traffic, the projected opening date for the new Arborway, has fewer lanes than the full 2035 design, though it leaves space for the future lanes to be added when necessary. Combined with other changes to the total design, it is a reduction of up to 22 feet of pavement for pedestrians to cross.
The extra lanes had been something of a poison pill, leading to a questionable choice between a blighting overpass or a crummy intersection. It's not clear how they would have helped drivers either, since they would have to merge again once they passed through.

But I also want to draw attention to a few statements:
As the Gazette reported earlier this monthtwo different versions of analyses showed occasionally widely different levels of service (LOS). [...] One version of the analysis was presented to the advisory group last October. A newer version was released last month following a six-week delay after a Freedom of Information Act (FOIA) request. In the newer analysis, some intersections had much worse LOS scores while some fared better. According to the design team, as the design evolves—with traffic lanes being added, subtracted or moved—LOS will improve or worsen at impacted intersections. 
“As design progresses and is tweaked, the [LOS] results will change,” MassDOT Highway Administrator Frank DePaola told the Gazette in a prepared statement. “The good news is, by making even small changes in a sophisticated traffic modeling system, we are allowed to see the effects of those changes in relatively short order.”

It's completely backwards to attempt to project "level of service" grades for the intersection in 2035, and then design based upon that. That is a sure-fire way to overbuild the road. Since "level of service" contains no provision for walking or bicycling, basing a project on it will completely ignore any issue but pushing automobiles down the road as fast as possible. This might be appropriate for a highway in the middle of nowhere, but it is a completely inappropriate attitude towards a densely populated region where people live and work, and where they like to be able to walk and bicycle as well as drive.

It's clear that the models they are using are extremely crude and subject to wild variation. The 17% growth in traffic they are projecting "is a number not seen anywhere else in the city." That means it is a massive overestimation. Trying to build a road that accommodates so much traffic will only lead to more cars trying to use it, degrading quality of life for residents. A self-fulfilling prophecy of doom. Instead of this destructive path of attempting to pursue guesstimated "level of service" goals, MassDOT should first be working to provide a corridor which is appropriate to the neighborhood, and then working within those constraints to provide safe traffic flow. Not the other way around.

Thursday, July 5, 2012

Quincy Center takes an inadvertent step forward

The Quincy Center station parking garage, which saw approximately half of its 872 spaces used on a weekday basis, is now closed indefinitely due to unsafe conditions in its 41-year old crumbling structure. One stop down, at the Quincy Adams station garage, there is approximately 75% weekday utilization of its 2,538 spaces, so there should be plenty of room for Quincy Center garage users. The Quincy Adams T station is a relatively newer infill station along the Braintree branch of the Red Line.

On a broader note, Quincy Center is changing and attempting to reinvent itself as a more urban neighborhood, in a big way. The garage there clearly did not serve that goal. In addition, the Quincy Adams garage is placed near the intersection of I-93 and Route 3, which is a much better location for a park-n-ride that needs to be able to accommodate and discharge thousands of vehicles in a limited span of time. The Quincy Center station is further up along the Burgin Parkway, which is a smaller arterial road, and not nearly as convenient for cars coming from the south. That is probably why the garage has seen relatively light usage compared to the other park-n-rides along the Red Line, even when it was open. Although I believe this closure was serendipitous, hopefully it will fit right into the plans for the renovation of the Quincy Center area, which is well positioned for a revival.

Sunday, July 1, 2012

Happy New (Fiscal) Year


Can you hear the fireworks? The MBTA has brought you a brand new fare increase! Well, actually those fireworks are probably some overeager teenagers who just got back from NH. And you didn't want the fare increase. But how much will it discourage daily ridership, which has been booming lately? A CTPS study suggests between a -3.4% and -7.8% effect, based on past experience. The corresponding increase in overall private vehicle-miles traveled is projected at +289,244, or 0.28%, while the increase in vehicle-hours is +17,491 (0.55%).

Other research, recently pointed out to me by Alon, also found that while the relative cost of private vs public transportation seemed to affect car usage, the correlation was not significant. On the other hand, an increase in the absolute cost for the private mode was linked with high confidence to a decrease in automobile usage. This model seems to imply that car usage and corresponding public transportation ridership could only be affected a small amount when fares change within a reasonable margin. Another interesting thing they found was that two of the most significant variables linked to car usage are size of the rapid-transit network (urban rail) and average speed of the roadway network.

Although these data come from East Asian cities, this result seems to agree with the general feeling of most people that fare hikes are tolerable, but service cuts are not. For people who depend upon a route, a service cut is almost tantamount to an eviction from their residence, as they may be forced to move elsewhere in order to continue to use the system (assuming they do not have other options).

In related news, Acting General Manager Jonathan Davis is crediting the recent surge in ridership to the front door-only policy:
The MBTA launched a pilot program on the E branch of the Green Line in January requiring all riders to enter and exit only through a trolley’s front door except during rush hour periods. The policy was expanded to the C branch in February, the D in April and finally the B in May, the first month when the back door ban was in full effect across all four branches.
Acting T General Manager Jonathan Davis told the Herald that the policy likely contributed to ridership on the light rail system rising 9.1 percent last month over the same period last year.
It seems that the T is grasping for straws here to justify the policy which inconveniences riders, increases dwell-times and slows down operations. The problem with GM Davis's reasoning is that the front door-only policy was not strictly enforced on the "B" and "C" until June. I say that as a rider and someone who spent the latter half of May wondering when they were going to start forcing me to exit through the front door. It seems a little premature to be pointing to these statistics and claiming that they are evidence of effectiveness.