Wellness and the Purple Line/CCT

The Purple Line/CCT project is nearing completion of its Preliminary Design Phase. On March February 28 MTA Purple Line staff and M-NCPPC planners briefed the Montgomery County Planning Board on the current status of several remaining design issues. Much of the briefing presented issues already presented at the recent MTA Neighborhood Work Groups, but there were some new renderings of the Silver Spring station, and also a new (at least to me) discusion of the Silver Spring Green Trail. The briefing is available at M-NCPPC 02/28/2013 Purple Line Briefing (PDF). Uncertainty still hung over the future of the project at the briefing because of the continued failure of the state legislature to address adequate funding for the state Transportation Trust Fund.

Written testimony was submitted to the Planning Board from a Bethesda resident and “Friends of the Trail” advocate Mary Rivkin requesting a Health Impact Assessment (HIA) be conducted by MTA. From the testimony submitted:

Need for Health Impact Assessment (HIA). While the requirement for an EIS is well understood, the equally pertinent HIA is not yet equally considered. The CDC points out that a “major benefit—is that it brings public health issues to the attention of persons who make decisions about areas that fall outside traditional public health arenas, such as transportation land use.” When we consider that the de facto park offers many health benefits to residents, changing the park to train tracks with a little trail running alongside should entail a formal analysis of the health impacts of the project. …

The full public testimony is on the record here (PDF), see the second of the two letters submitted.

Ms. Rivkin requests a full assessment of the health impacts of the transportation project, but her comments address only the issues associated with the Georgetown Branch Trail in her immediate neighborhood and are biased against the Purple Line. If an HIA assessment is done it would follow CDC Health Impact Assessment Toolkit guidelines which support the CDC Transportation Recommendations. Those CDC recommendations strongly support using transportation design to improve public health, including expanding public transit, promoting “active transportation” with transit, and healthy community design with access to affordable transportation. Further, an HIA would measure health impacts of the Purple Line on neighborhoods over the entire 16-mile project length, not just the Bethesda neighborhood that is of focus of concern to Ms. Rivkin.

One does not need to be a health science professional to get a good sense of whether an HIA would support Ms. Rivkin’s opposition to the Purple Line. I take a brief look here at several of the major issues, grouped in catagories roughly similar to those suggested by CDC guidelines and Ms. Rivkin’s request:

  • The health benefit from trail use
  • The health benefit from transit “active transportation”
  • Trail safety and neighborhood connectivity
  • Tree cover, and public access to green space

I only look at the Bethesda-Silver Spring area, but that is enough to get the gist of what an HIA of the entire project would find.

1 – The health benefit from trail use:

The public health benefit of getting people more active to combat obesity and other disorders is well known, and I’ll not belabor the issue here. Trail users will enjoy Lenny Bernsteins’ observations on how the Capital Crescent Trail supports physical activities of walking, running and cycling, which appeared in the Wellness section of the Washington Post on this February 26: In praise of a reliable workout buddy. Mr. Bernstein withholds judgement about whether the changes to the CCT east of Bethesda (a.k.a. Georgetown Branch Trail) that the Purple Line will bring would be for good or bad.

More people will benefit from physical activity on the trail if the Purple Line/CCT is built as proposed than benefit from the trail as it exists today. This is often counter-intuitive to Bethesda residents like Ms. Rivkin, but strong evidence for this can be found in the 2006 CCCT Trail Traffic Survey:


Trail use at Elm Street Park is less than 1/2 the trail use at Bethesda Avenue only a few hundred feet to the west. And trail use near the eastern end of the trail, at the Grubb Road access, is barely more than 1/10 that at Bethesda Avenue. Clearly the Georgetown Branch Trail east of Bethesda is very underused compared to the CCT. This data led to this major conclusion in the trail traffic survey report (emphasis mine):
“Trail use at Grubb Road peaks at 80 uses/hr on weekends, and the projected weekly use is 2500+. This is a very respectable use compared to many local neighborhood trails, but falls far short of the potential the CCT has to be a regional trail connecting downtown Bethesda with downtown Silver Spring. The stark contrast between observed trail use at Grubb Road and elsewhere on the CCT invites a public discussion about what is needed to complete the CCT to better serve Silver Spring and its neighborhoods.”

The major reason that the Georgetown Branch Trail is underused is shown here:


East terminus of the off-road Georgetown Branch Trail,
in an industrial park at Lyttonsville

The off-road Georgetown Branch Trail ends ubruptly over 1-1/2 miles from downtown Silver Spring, in an obscure industrial park at Stewart Avenue. The trail continues from there into Silver Spring in traffic as an on-road bicycle route, with many turns, numerous stop signs and traffic signals, and with at-grade crossings of several busy highways including two six-lane state highways.

Another reason for the Geogetown Branch Trail being underused is pictured here:


Georgetown Branch Trail near Stewart Avenue

While some trail users, mostly joggers, like the crushed stone trail surface on the Georgetown Branch off-road section, many find that the uneven and often muddy conditions are not good for cycling. It is also not well suited for the mobility impaired who need walkers or wheelchairs, or for parents with baby strollers.

The length of the Georgetown Branch Trail east of Rock Creek, from Rock Creek to downtown Silver Spring, is equal to the length of the trail west of Rock Creek, from Rock Creek to downtown Bethesda. The population of Silver Spring and its neighborhoods is comparible to that of Bethesda. The business and employment activities of the two urban centers are about equal. Both have very active transit centers. If the CCT (a.k.a. Georgetown Branch Trail) were to be extended as a paved, good quality off-road trail into downtown Silver Spring, then the number of people with easy access to the off-road trail between Bethesda and Silver Spring would be approximately doubled from what it is today. The completed trail would have about twice the number of useful destinations for all users than does the existing incomplete trail. Important regional trail connections with the Metropolitan Branch Trail and the Silver Spring Green Trail would be completed.

The Purple Line will change the nature of the trail in Chevy Chase, to have less shade and less of the character of a park. But for every trail user who might stop using the trail as often because it feels less like a park in Chevy Chase, there would be several new trail users happy to use the trail because it is would be more accessible from their home in Silver Spring or would better reach a Silver Spring destination.

2 – The health benefit from rail transit “active transportation”:

It is easy to focus only on biking and walking on the trail when we look at getting people to be more physically active in their daily lives. But using transit instead of driving a car has been shown by numerous studies to bring very substantial health benefits from more physical activity. Here are just two:

  • Science Daily described a study published in the American Journal of Preventive Medicine by the University of Pennsylvania, Drexel University and the RAND Corporation. The study found that construction of a light-rail system (LRT) resulted in increased physical activity (walking) and subsequent weight loss by people served by the LRT.

    “Using two surveys, one collecting data prior to the completion of an LRT in Charlotte, North Carolina, the second after completion, investigators found that using light rail for commuting was associated with reductions in body mass index (BMI) over time. Specifically, LRT reduced BMI by an average of 1.18 kg/m2 compared to non-LRT users in the same area over a 12-18 month follow-up period. This is equivalent to a relative weight loss of 6.45 lbs for a person who is 5′5. LRT users were also 81% less likely to become obese over time.”

  • The CDC Health Impact Assessment Toolkit lists several studies of active transportation under “Resources”. The first study cited is from the American Journal of Preventive Medicine:
    Besser, L. M. and A. L. Dannenberg (2005). “Walking to public transit: steps to help meet physical activity recommendations.” Am J Prev Med 29(4): 273-280.

    This national study found that Americans obtain daily bouts of physical activity by walking to and from transit. The median amount of time spent in commuting to transit on foot is 19 minutes, but people of lower socio-economic status and minorities walked further to transit stops. Rail users walked further than bus commuters.

    The CDC clearly recognizes the important benefit that walking to transit can bring to public health, and highlights it in its HIA toolkit. Its CDC Transportation Fact Sheet (PDF) lists expanding public transportation among its major recommendations for improving public health through good transportation policy.

We can draw a point of comparison on the potential public health benefit from walking to transit with the benefit on the existing Georgetown Branch Trail from walking and biking. An early MTA estimate of the transit use at the Bethesda Purple Line platform is 11,500 boardings each day, from MTA Purple Line station ridership table (PDF). Since approx. 4/5 of future Purple Line riders are estimated to convert from riding buses, I’ll be conservative and not count that 4/5 even though the studies show users will walk further to rail transit stations than to bus stops. This still leaves us with 2,300 “new” transit riders boarding at the Bethesda Purple Line station each day, or approx. 16,100 each week. And this is only counting boardings, i.e. those who leave the station and travel east, and not those who are alighting, i.e. those who arrive on the Purple Line from stations to the east. Even under these extremely conservative assumptions, the estimated 16,000+ people getting a health benefit from walking to Purple Line transit at Bethesda will exceed the number of people who now use the Georgetown Branch Trail for walking or biking, 10,000+ weekly as counted at Elm Street Park. And this point of comparison is only for the Bethesda station. When you consider that the Purple Line is projected to have 69,500 daily boardings at 22 stations, it is clear the public health benefit of the 16 mile long Purple Line for active transportation will eclipse that realized today by walkers and cyclists on the 3 mile long off-road Georgetown Branch Trail.

An HIA will show that a Georgetown Branch Trail that will be completed into Silver Spring with the Purple Line would serve more walkers and cyclists than does today’s badly underused trail. It will also easily show that the number of transit users who will get a significant active transportation health benefit by using the Purple Line would eclipse the number of trail users. The public health implication is clear – to increase physical activity benefits for the largest number of people, building the Purple Line/CCT project is a far better choice than would be “no build”.

3 – Trail safety and neighborhood connectivity.

Ms. Rivkin’s request for a full HIA of the Purple Line asserts that building the Purple Line on top of the existing trail will make the trail less safe, and will destroy safe pedestrian connectivity between neighborhoods. But the request only mentions neighborhoods and street crossings in Chevy Chase. The request makes little mention of neighborhoods along 1/2 of the length of the Georgetown Branch Trail, the part that lies east of Jones Mill Road.

The existing Georgetown Branch Trail looks like this in Silver Spring neighborhoods:
Georgetown Branch Trail crossing of 16th Street

Georgetown Branch Trail crossing of 16th Street

The Georgetown Branch Trail is now only an on-road cycling route through the neighborhoods of Lyttonsville, Rosemary Hills, North Woodside, Woodside and the Silver Spring Urban District. These neighborhoods are separated from each other by the CSX railroad tracks, the 16th Street six-lane State Highway (pictured above), Spring Street, and Colesville Road which is yet another six-lane State Highway.


Neighborhoods are divided by six-lane highways and a railroad.
(The existing on-road Georgetown Branch “trail” is the green line.)
Source: www.cctrail.org

The Purple Line/CCT project proposes to build a completely off-road, 12′ wide shared use trail, with grade-separated bridges and underpasses of the railroad tracks and all major roadways, complete into the Silver Spring Transit Center. This is far from being the “little trail” Ms. Rivkin describes in her request.

The trail in the Chevy Chase neighborhoods would be rebuilt to maintain the connectivity between Chevy Chase neighborhoods similar to what they enjoy now. The loss of the grade-separated crossing of Wisconsin Avenue would be compensated for by new grade-separated crossings of Connecticut Avenue and Jones Mill Road. Trail users would be separated from transit tracks by a landscaped buffer and fence throughout the length of the trail. There is extensive experience nationwide with Rails-with-Trails, and they have been shown to be very safe.

A systematic survey of trail safety and neighborhood connectivity issues would conclude that building the Purple Line and extending the CCT into Silver Spring would improve trail safety and neighborhood connectivity.

4 – Tree cover, and public access to green space

Opponents of the Purple Line make the claim that Montgomery County has declared the lower county area to be deficient of parks and green space. To remedy that, they ask that the Georgetown Branch Corridor be declared a park, and that transit uses be excluded.

It may be true that parts of lower Montgomery County are deficient of parks for uses such as ballfields, dog parks and play lots. But lower Montgomery County has a higher percentage of tree cover now than does the rest of the county:


Existing tree cover density in Montgomery County
(click on the image for the full map with legend)
Source: A report on Montgomery County’s
existing and possible tree cover

The project that produced the map above applied the USDA Forest Service’s TC assessment protocols to Montgomery County. The analysis was conducted based on year 2009 data by the University of Vermont Spatial Analysis Laboratory.

The Chevy Chase Lake sector plan has a more detailed map of the tree cover at the central section of the off-road Georgetown Branch Trail:


Existing tree cover in the Chevy Chase Lake area
source: Chevy Chase Lake Sector Plan – Appendix 8, Environment (PDF)

The Chevy Chase Lake sector now has a tree cover of 52%. The source document for the sketch above states that the desired minimum tree cover is 30%. The source document notes that the majority of tree cover in this sector is from the Coquelin Run stream valley. As can be seen by the separation distance between Coquelin Run and the Georgetown Branch Corridor, the Coquelin Run tree cover would not be impacted by changes in the Georgetown Branch corridor. It is also evident that the residential areas throughout the sector contribute significant amounts to the total tree cover in this area.

The tree cover along the Georgetown Branch is evident in the Chevy Chase Lake Sector Plan map above, but a significant proportion of that is from adjacent private properties. A significant number of trees will also remain within the 100′ wide r.o.w. in the Chevy Chase Lake sector after Purple Line construction since the expected limit of construction is only 60′ wide. There will be some restoration of green space within that 60′ as small trees and large shrubs from the project’s landscaping become established.

The most important contribution of tree cover in this area is not from the Georgetown Branch corridor, nor from Coquelin Run. It is from Rock Creek Park. The Rock Creek Stream Valley Unit #2, the portion of Rock Creek Park between Connecticut Avenue and East-West Highway, has 277 acres, most of it in deep woodland. See the Rock Creek SVU2 map (PDF). This dwarfs the patchy, thin line of tree cover that is contributed by the approx. 17 acres along the Georgetown Branch corridor.

Public access to park land is an issue to be considered. It is argued that children in Chevy Chase will lose easy access to green space if the Purple Line were to displace the existing trail. But children who live in Rosemary Hills, Lyttonsville, and the Silver Spring urban district live in areas that need access to green space at least as much as those from Chevy Chase neighborhoods. For them, Rock Creek Park is now relatively inaccessible. Completion of the Capital Crescent Trail through their neighborhoods together with completion of the trail ramp between the CCT and the Rock Creek Trail will give them safe off-road access to a regional park.

Proposed CCT connection to Rock Creek Trail
Source: MTA Lyttonsville Area Map

The loss of any tree will be felt by trail users if it is a tree that provides shade. But a fair assessment of tree cover within the Purple Line/CCT service area will show that the loss of tree cover from Purple Line construction would have a very minimal impact on the total tree cover in lower Montgomery County. Access to Rock Creek Park will be greatly improved for neighborhoods east of the park.

Do we need yet another big study?

The strong contribution that good public transit and urban trails can bring to public health by increasing physical activity is well recognized by the CDC in its CDC Health Impact Assessment Toolkit and CDC Transportation Recommendations. Clearly any Purple Line/CCT HIA performed under CDC guidelines would return a report that favors the project. So why would “Save the Trail” advocates push for an HIA this late?

Opponents of a project will often ask for more study, regardless of how late it is in the project development or how many studies have come before. If refused, than the opponents will assert that the project is being rushed forward without “due process”. If the study is done and the result favors the project, then the opponents will ignore the results. They will have harmed the project’s chances to succeed by adding more cost and delay.

The Purple Line/CCT project has undergone a thorough design and review process. It must comply with a comprehensive and demanding study and reporting process set by the US DOT to compete for federal funding. The process includes a very comprehensive EIS, and a rigorous public review proceedure. An HIA is not required for this project.

We do not need this obstruction and delay – we do not need the HIA.

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4 Responses to “Wellness and the Purple Line/CCT”

  1. Dan says:

    Thank you for a thorough response and your counterarguments. The sections on tree cover, access to recreation, and the condition of the trail from the perspective of the Lyttonsville end give a needed balance to the objections from some on the Chevy Chase side.

  2. Woodsider says:

    Agree with Dan…excellent post. As my old pal Mr. Spock says: “the needs of the many outweight the needs of the few”.

  3. Brian says:

    Thank you for the discussion. Your analysis assumes that the only way we can have a better trail connecting Bethesda and Silver Spring is if we build the Purple Line. An improved trail, however, can easily be built without the Purple Line at a fraction of the cost. With that in mind, I don’t believe that an HIA will so “clearly” return a report favorable to the project.

  4. admin says:

    Brian:

    I think you are wrong on two counts:

    1) The health benefit from a higher level of physical activity from Purple Line users will always overwhelm the health benefits from the physical activity from using the trail, whether the trail is extended or not. That is because the transit users will always outnumber the trail users by an order of magnitude.

    2) You say an improved trail can easily be built without the Purple Line. Not true! The largest single improvement to get more benefit out of the trail would be to extend it into downtown Silver Spring as a direct off-road trail. How do you propose to “easily” obtain the crucial CSX r.o.w. to make that possible? Or do you have another route in mind? What is it? Many people have been wanting to find an easy alternative to building the trail into Silver Spring along the CSX corridor, with no success.

    Wayne Phyillaier

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