‘Metro 101’

Transit Walk Sheds and Ridership

August 11th, 2014 8 comments

Metro cares about transit walk sheds because more households accessible to transit by walking translates directly into more ridership.

We’ve been focusing a lot on transit walk sheds lately. We’ve shown that the size of a transit walk shed depends heavily on the roadway network and pedestrian infrastructure, and that these sizes vary dramatically by Metrorail station. We’ve also demonstrated that expanding the walkable area can make hundreds of households walkable to transit.

But why do we care so much about walk sheds? Because larger walk sheds mean more households in the walk shed, and that means ridership. For example, we’d be hard pressed to find many households in Landover’s small walk shed, so it’s no surprise that walk ridership at that station is low. On the other hand, thousands of households are within a reasonable walk to Takoma’s larger walk shed, and walk ridership there is much higher.

In other words, the more people can walk to transit, the more people do walk to transit – and data across Metrorail stations prove it:

Correlation between Households in the half-mile walk shed, and AM Peak ridership, by WMATA Metrorail station entrance

More households in the walkable area around a Metrorail station means higher ridership

Read more…

Eight-Car Trains on Metro is Equivalent to Widening I-66 in Arlington by Two Lanes

July 14th, 2014 8 comments

Adding two extra cars to a six-car Metrorail train might not seem like much, but it is equivalent to widening I-66 through Arlington by two lanes. Plus, it’d likely be cheaper and faster for commuters, too.

Sometimes it’s hard to wrap one’s head around how just many people Metrorail can move. But where Metrorail operates in heavily congested corridors, seemingly small improvements can yield big results. In fact, matching the capacity of all eight-car trains system-wide would require 16-18 lanes of freeway into downtown, each way.

Orange Line Metro train from I-66. (Photo by wfyurasko, click for original)

To match the capacity of eight-car trains on Metro, we’d have to widen I-66 in Arlington by at least two lanes. (Photo by wfyurasko, click for original)

In Arlington for instance, going to eight-car trains on the Orange Line as part of Metro 2025 is like widening I-66 by two lanes.  Let’s do the math:

  1. One lane of highway can move around 2,200 cars per hour, at its theoretical maximum.
  2. Today, every morning Metrorail runs about 18 trains per hour eastbound on the Orange Line through Arlington, and about a third are scheduled eight-car trains. That’s a train every three minutes, and equates to around 121 rail cars per hour, or 12,060 passengers per hour.
  3. By 2025 with eight-car trains, Metrorail will be able to run 21, eight-car trains per hour eastbound on the combined Orange and Silver Lines, which equates to 168 cars per hour.
  4. This means Metro 2025 will bring the line’s capacity to 16,800 riders per hour, or an increase of 4,740 passengers per hour.
  5. To accommodate 4,740 more people on I-66 at 2,200 cars per hour, 2 people per car, we’d need 4,740 / 2 / 2,200 = 1.1 highway lanes in each direction.

That means we’d need at least two new lanes on I-66 to match the capacity of Metro 2025. In addition, eight-car trains would be cheaper, and would likely move people faster through the corridor.

  • Eight-car trains on Metro would be over two times cheaper: the estimated cost to widen I-66 works out to about $3.50 per rush-hour trip over the life of the project, whereas Metro 2025 would be about $1.50.
  • Metrorail would likely move travelers faster than I-66 in the end.  Orange Line trains today normally run at around 35 miles per hour, while congested travel speeds on I-66 average around 18 miles per hour. While new highway lanes might move cars faster at first, the improvements would eventually be eroded by growing congestion.
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What’s the Ideal Size for a Transit Walkshed?

July 8th, 2014 2 comments

Large transit walksheds are great, but how big is big enough?

In other posts, we have described what a transit walkshed is, and how changes can be made to the pedestrian network to increase the walkshed area.  Here, we explore how big is big enough.

The diagram below shows a half-mile circle around a transit station.  If the station were located in a field of grass or on a massive parking lot, the walkable area of the circle would be the circle itself, 100% of the half-mile buffer around the station would be accessible by foot.  Unfortunately, that wouldn’t bode well for transit use, since there wouldn’t be any origins or destinations within that walking distance.

Ideal Walkshed DiagramNow, let’s lay a perfect grid of streets across that half-mile buffer.  The street area is where people can walk, and the remaining area contains houses, shops, mixed-use development, etc.  The resulting walkshed for the station begins to look like a diamond inscribed inside the circle.   The smaller the blocks (the closer the streets are to one another) the more the walkshed resembles a perfect diamond that has a diagonal distance equal to the diameter of the circle.  If you take the area of the diamond and that of the circle and compare them, you find the walkshed (square) covers 63.7% of the circular station area buffer.

So if you have a perfect grid and get 63.7% coverage, how can you get any better?  For one, diagonal streets can increase the coverage: if two diagonal streets were added to the grid, intersecting in the center of the circle at the transit station, the square walkshed would turn into an eight-pointed star, increasing coverage even more, but not by much.

An good example of a walkshed greater than 63.7% is that of the Takoma station.  Featured in a previous post, we recently calculated a 91% coverage for Takoma.

It is difficult to pick an ideal size for a transit walkshed.    A larger percentage could be beneficial, but the additional roadway network needed to expand the coverage beyond 63.7% may result in less area dedicated to potential transit origins and destinations.  (Remember the station in the parking lot?)

What Metrorail stations do you feel have good walkshed coverage?  In  your opinion, where can we improve?

 

 

We Had Bus Lanes a Half Century Ago and We Can Again

July 7th, 2014 7 comments

Despite having two million fewer people, our region used to have 60 miles of bus lanes.  It’s time to revive them.

Bus Lane on 14th Street in DC

Bus Lane on 14th Street next to the National Mall in the early 1970s

Did We Really Have That Many Bus Lanes?

Yes.  In the 1960s and 70s before Metrorail was built, Washington and its surrounding inner suburbs relied heavily on its bus system to get around, with very frequent service on a number of major streets.  According to our records (linked at the bottom of this post), the first bus-only lane was installed in 1962 on 16th Street NW in DC, generally between H Street NW and Florida Avenue NW [DDOT Fact Sheet, p. 6].  This was followed by dozens of miles of rush-hour and full-time installations, as shown in the map and table below.  Streets in red indicate bus lanes that were implemented as of 1976, while streets in black and blue represent bus lanes that were planned but, to our knowledge, never put in place.

Read more…

How Can The Coverage of Transit Walk Sheds Be Increased?

July 1st, 2014 2 comments

Pedestrian infrastructure can cost-effectively increase coverage of transit walk sheds.

The roadway networks of most station areas are mostly unchangeable.  Existing structures on private property create unmovable barriers and  usually prevent new roads from being added to the network.  However, there is still opportunity to add pedestrian facilities that would increase a station’s walk shed in a relatively cost-effective way.

Take the example of Southern Ave Metrorail station.  We previously noted how a large number of customers drive to the station from between one and three miles away.  We discussed several reasons for this tendency to drive to Southern Ave, including the proximity to parks on both sides of the station.  The map below shows the transit walk shed of Southern Ave station.

Current walkshed of Southern Ave station.  The area with the orange dotted border contains over 1,200 households that could be within a half mile of Metrorail if a direct pedestrian connection were built.

Current walkshed of Southern Ave station. The area with the orange dotted border contains over 1,200 households that could be within a half mile of Metrorail if a direct pedestrian connection were built.

 

But what if a pedestrian path could be built to connect the station to the neighborhood to the north?

If a well lit, safe pedestrian path were constructed between the station and the orange-dotted area on the map, it could expand the walkshed to include up to 1,200 additional households in DC.  This new connection would likely increase ridership at Southern Ave. and might even generate enough additional fare revenue to fund the construction of the trail.

Metro’s Office of Planning is currently evaluating the walk sheds of our rail transit stations.  What other opportunities do you see for cost-effectively increasing the walk sheds around Metrorail stations?

Silver and Blue Line Changes: Over a Decade in the Making

June 30th, 2014 6 comments

Recent and upcoming Metrorail service changes to accommodate the Silver Line have been in the works for over a decade, and are better for Blue Line riders than originally planned.

Metrorail Service Changes with the Silver Line Opening on July 26, 2014

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What’s a Transit “Walk Shed”?

June 10th, 2014 6 comments

Metro will soon be measuring how much growth happens in places that are walkable to transit. Here’s an in-depth look at how we define “walkable” to Metrorail stations and Metrobus stops.

Quarter-mile walk (by the network) for regional Metrobus stops and Metrorail stations

Areas reachable on foot from regional Metrobus stops and Metrorail stations

Metro’s new Connecting Communities metric will measure annual household growth in our region that occurs within the “transit shed” – the catchment area around transit service that generates walk ridership. And improving walkability can be an incredibly cost-effective way to reduce congestion and increase transit ridership.  Let’s take a closer look at how we defined what’s “walkable to transit.”

How Far is Walkable? First, we defined walking distance as a half-mile from Metrorail, and a quarter-mile from Metrobus, for a number of reasons:

  1. Of all the passengers who walk to Metrorail each morning, the median walking distance is just under a half-mile (0.35 miles, actually).  Riders walk farther to some stations than others, but the systemwide average is just shy of a half-mile.  Since rail riders are on average willing to walk a little under a half-mile today, it is reasonable to use a half-mile as an upper limit for walking in the future. (We don’t have similar survey data on Metrobus - yet.)
  2. The land use within a quarter- and half-mile is where we see the strongest effects on ridership on Metro today. More on this below.
  3. Academic literature supports the half-mile radius from rail transit as no better than any other distance, particularly for the link between households and ridership.
  4. Practically, setting the distance any farther than 0.50 and 0.25 miles increases overlap with other nearby stations and bus stops, which increases computational complexity. Read more…

Solving the Region’s Congestion Woes – One Step at a Time (Part 3 of 3)

March 31st, 2014 2 comments

Making every Metrorail station area walkable could reduce regional congestion without breaking the bank.

This is part three of a three-part series.

In the previous two posts we’ve laid out a case for making all transit stations walkable as quickly as possible.

  1. Increasing walkability and density at station areas has huge impacts on transit mode share and can take tens of thousands of cars of the road every single day.
  2. At a regional level, walkable station areas have an equivalent impact on congestion as a quarter trillion dollars in “last mile” infrastructure (see pages 37, 38, 43, 48).

Maximizing the capacity of the existing transit network while intelligently investing in station area connectivity would combat regional congestion just as effectively as trying to “build our way out of the problem”. And unlike many potential interventions, the market actually wants to do this for us.

Perhaps it is time to harness these market forces to make the areas around our transit network walkable and implement this low-cost congestion-busting paradigm. As for where to begin – well, we have a few suggestions…

Existing Walkability Near Metrorail Stations

The map below shows the range of existing walkability conditions near the Metrorail network and helps answer the question of how much of a half-mile radius of each station a person can walk to. The higher the percentage, the better the pedestrian network coverage. As shown, many of the station areas are under performing relative to their potential walkability. If walkability = connectivity and connectivity = mode share, then just imagine the impact on the region’s roads if we could focus on taking station areas with low accessibility and invest in some relatively easy, short-term solutions like sidewalks, pedestrian bridges, crosswalks, and smart, transit-oriented development to take maximum advantage of the existing Metrorail system and take tens of thousands of cars off the road each day.

How walkable are our region's Metrorail stations?

How much of the area within a half-mile of our Metrorail stations can you walk to?

Read more…

Solving the Region’s Congestion Woes – One Step at a Time (Part 2 of 3)

March 24th, 2014 2 comments

Improving pedestrian connectivity takes cars off the road at a formidable clip – rivaling the power of all of the region’s planned roadway additions and “last mile” transit connections.  Cheaply and quickly. 

This post is part two of a three-part series.

The data is finally in, and we now know that walkable station areas result in fewer motorized trips, fewer miles driven, fewer cars owned, and fewer hours spent traveling. And when we improve the pedestrian and bicycle access and connectivity to Metrorail station areas, ridership goes up, putting a major dent in congestion by taking trips off the roadways. Earlier, we discussed what it means to build walkable station areas and research shows the tremendous benefits to the region of making this a priority.

First, our data confirms that when walking access to transit is improved, transit ridership goes up – way up. In the 2040 Regional Transit System Plan (RTSP), we stress tested TPB’s transportation model to improve walkability to the transit network and saw huge increases in transit linked trips.  These trips go up by about 10% region-wide and we get an increase in transit mode share for all regional trips by 0.5%.  That’s over and above the roughly one percent increase in mode share we anticipate occurring as a result of building the entirety of the CLRP, an impact about half that of constructing all of that transit.

Source: Regional Transit System Plan

Source: Regional Transit System Plan

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Solving the Region’s Congestion Woes – One Step at a Time

March 17th, 2014 1 comment

One solution to the region’s crippling congestion could be right under our feet – literally.

This post is part one of a three-part series.

Illustration of possible walkability improvements that could occur in/around Tysons Corner. From Regional Transit System Plan

 

The region is abuzz with $220B of planned new transportation investments – the Purple Line, HOT Lanes, new streetcar lines, and additional roadways. Though there is not one dollar currently pledged to add capacity to Metro, these other investments may help the region chart a course away from leading the country in congestion (pdf).

However, for a quarter trillion dollars, one would expect that collectively these projects would have significant impacts on the region’s congestion. While there are some benefits – vehicle miles traveled (VMT) per capita are expected to decline and  transit mode share may increase by one percent – overall increases in VMT are expected to outpace road construction, leading to a 38% increase in the number of lane miles of congestion (pdf). But is there another way to get more bang for our buck?

Make station areas walkable. Every one of them. Now.

Read more…