The Maps and Figures Behind Transit Use Numbers

ARC’s most recent Regional Snapshot focuses on transit usage in the Atlanta region. Two images from that document offer valuable insight into why the transit use statistics bandied about for Atlanta may be misleading.      

 Transit critics frequently cite the Census Bureau’s American Community Survey to argue that Atlantans use transit at a low rate.  As discussed here before, this particular stat underestimates transit use because of the question’s phrasing.  ARC reached the same conclusion in the Regional Snapshot:  

The question on the American Community Survey only asks respondents how they “usually” got to work during the last week. The ridership figures would  be akin to the “Home-Based Trip” in Chart 4, which comprise 45 percent of all transit trips.  Thus,  the ridership figures reported in the American  Community Survey underestimate actual transit ridership because the survey only captures work trips.

The pie chart above shows the results of ARC’s On-Board Transit Survey, which polled actual transit users in Atlanta. This survey shows that only 45% of transit trips are for work.  The other 55% of trips are by students, retirees, shoppers, Falcons fans, tourists, or folks leaving the house for anything other than work.  Yet this 55% of trips would not result in a YES to the American Community Survey question.   ARC’s On-Board Transit Survey provides empirical proof that the Census numbers systematically under-report transit usage in metro Atlanta.

  The second figure shows the areas in metro Atlanta that are served by transit (bus service) and “high quality transit” (rail service).  The transit areas, shown in blue, cover about 36% of the region’s total population.  The brown areas, covering approximately 7% of Atlanta’s population, are the areas served by rail transit.  For 2/3 of Atlantans, taking transit isn’t a viable option where they live.  And rail transit isn’t availabile for 90% of Atlantans where they live.

Transit critics assert that Atlanta should not invest in transit because people won’t use it and use the  Census’ low-ball numbers to support this proposition.   But as the map shows, over half of Atlantans can’t use transit where they live.  And as the chart shows, those Atlantans served by transit use it at a higher rate than the Census data reports. 

Is the problem that Atlantans won’t use transit, or that they can’t?

Judged to Scale

With all the facts and opinions swirling around the TIA, Politifact Georgia has done a great job of fact checking many of the statements offered by supporters and opponents of the referendum.  A full listing of their “Transportation Tax: Truth, Lies and Gridlock” series is here

They recently reviewed the statement that the TIA would add 16 miles of road for every mile of rail and found the statement “mostly true.” (They calculate the ratio as 17.5 : 1).  But what does that ratio mean?  A mile of rail is obviously different than a mile of road; they have different costs, accommodate different numbers of travelers, and serve different needs.  So is a 17 : 1 ratio good or  bad? Beyond the fact checking, the ratio also requires a frame of reference.

According to the Georgia DOT, the ten county Atlanta region currently has 39,900 lane miles of road.  The latest entry in the National Transit Database reports that MARTA has 96 track miles of rail.  Including the under-construction Downtown Streetcar will add another 2.7 miles of rail, for a total of 98.7 track miles in the ten county region.  

Politifact reports that the TIA would fund 21 miles of new rail, a 21.3% increase from the baseline.  Adding 365 miles of road (also Politifact’s number) would increase metro Atlanta’s road mileage by 0.9%. 

Comparing the TIA ratio to the status quo is also an interesting exercise.  Politifact calculates the road to rail ratio for the TIA as 17 to 1.  Using the GDOT and National Transit Database numbers, the ratio for the existing system is 404 to 1. 

So back to the original question – what does 17 to 1 mean? 

It means that the TIA would build rail at a dramatically higher rate than metro Atlanta has historically.  It means that the TIA would fund a significant increase in Atlanta’s total rail mileage and a negligible increase in its total road mileage.  Atlanta’s historical focus on road construction certainly skews the baseline for any road/rail comparison heavily in favor of roads.  But how we have spent money in the past is a necessary reference point in deciding whether the TIA is a step in the right director or simply more of the same.

Shoulder Lane Update

Georgia DOT recently presented travel time data for the Georgia 400 shoulder lane project. Although it only contains the first three days’ worth of data, the presentation shows a clear day to day improvement.  By the third day, travel times had improved upon the average pre- shoulder lane travel times.  A larger verion of the chart is here.

It will be interesting to see how travel times compare over the coming months.

LaHood Weighs in With the Conference Committee

Members of the U.S. Senate and House of Representatives are now into their third week of conference committee, trying to hammer out a compromise surface transportation reauthorization bill.  

The Senate bill, although not perfect, represents a reasonable refinement of the government’s policy on transportation funding. And the Senate passed its bill in bipartisan fashion, an increasingly rare event in these polarized political times.  In contrast, the House was only able to pass a bill after a series of misfires and a divisive party line vote.  Many of the issues that split the House – and even the Republican caucus – have nothing to do with federal transportation funding.  How to regulate coal ash…  Whether to roll back federal environmental review under NEPA… Whether to approve the Keystone XL pipeline.

 Ray LaHood, formerly a Republican Congressman but now the Obama Administration’s Secretary of Transportation, weighed in last week with a number of reasonable recommendations.  LaHood argued that any bill coming out of conference committee should:   

  • Not adopt the radical changes to NEPA in the House bill, which “threaten[] the air we breathe and the water we drink;”
  • Support efforts to consolidate programs, focus on national goals, performance and accountability, and continue the ban on earmarks;
  • Continue the successful, merit-based grant programs such as the TIGER and high speed rail programs;
  • Maintain sufficient investment in the New Starts program to deliver the important projects in the pipeline;
  • Not eliminate the requirement that Congestion and Air Quality Mitigation funds actually improve air quality, as proposed in prior versions of the House bill;  and
  • Preserve the Senate provisions that maintain the flexibility for public transportation “operations,” allowing transit agencies of all sizes to maintain service during a fiscal crisis.

His giant, 100 point font signature on the letter underscores the fact that he got each of these points right.



When More Is Less

As the AJC , WSB, and Creative Loafing have reported, the GA 400 shoulder lanes got off to a less than auspicious start.  GDOT insists that travel conditions will improve once drivers become familiar with the new lanes.  But their colleagues at the North Carolina DOT may disagree.

The Raleigh News and Observer’s Cross Town Traffic blog reports on a curiously comparable situation in North Carolina.  NC DOT decided to add  a third lane for a short segment of I-40 near Clayton, North Carolina.  But their studies showed that traffic ran smoother and faster with two lanes than with three.

What happened?

[The lane addition] created a rush-hour bottleneck caused by drivers who move into the new lane as it opens up and then try to squeeze back into line in the other two lanes, when the third lane ends.

Their solution?

DOT closed one of three lanes on I-40 and one of two lanes on U.S. 70 as it merges with I-40. The lane slimming was called temporary in September, but DOT will install lane markings to make it semi-permanent on Wednesday. 

The problem here is that switching lanes creates “friction” in the flow of traffic.  One study estimated that removing a car from a lane saves 0.8  to 1.2 seconds but adding that car back into the lane loses 1.44 to 2.19 seconds.  So the net effect of switching out and then back into a lane is to slow down traffic by 0.6 to 1.2 seconds per car.   Add that up over thousands of cars and it becomes clear why two lanes moved faster than three in North Carolina, and why the shoulder lanes may not provide much of a solution for GA 400.

GDOT should try to maximize the performance out of our existing transportation system.  But new capacity isn’t always the answer and, in North Carolina and perhaps north Atlanta, more capacity sometimes means less performance.

People like Walking. And Biking Too.

 As Congressional debate continues over the fate of the next transportation reauthorization bill, America Bikes released a poll showing strong bipartisan support for funding bike/ped projects.  According to the America Bikes poll:

  • 83 percent of all respondents support maintaining or growing the federal funding streams that pay for sidewalks, bikeways, and bike paths.
  • 80 percent of Republican respondents and 88 percent of Democrat respondents think Congress should maintain or increase federal funds for biking and walking.
  • 84 percent of Southerners reported support for maintaining or increasing funding for sidewalks and bikeways.
  • 91 percent of respondents between the ages of 18 and 29 support continuing or increasing biking and walking funds.

Given that metro Atlanta’s current investment in bike/ped infrastructure is effectively a rounding error in the total budget, perhaps the more surprising conclusion is that anyone can imagine spending less.

Death of the Exurbs Part 2….

… this time as an “infographic.”

The site ArchDaily has a series of infographics on the various trends that are merging to undermine the economics of exurban growth.  Some of this data and the result have been discussed here before but Arch Daily elegantly presents this information in a simple and compelling fashion.

A picture is worth a thousand words.  And a good infographic is worth at least that many studies and reports.

What to Build in the Northwest Corridor?

Connect Cobb's Map of Potential Transit Corridor Alignments

 The escalating chatter in the TIA campaigns and the public meetings for its NEPA analysis have both raised an important question: what is the best transit project for Cobb County? 

The Saporta Report does an excellent job of outlining the questions facing the “high quality transit” project contemplated for Northwest Atlanta.  Light rail or bus rapid transit?  Should it be built along the interstate (to save money) or run along US 41 (to spur economic development)?  Two recently released publications  support the same conclusion: light rail line along US 41 is the best transit answer for the Northwest Corridor.

The Journal of Transport and Land Use published a special issue dedicated to exploring the concept of “value capture.” Value capture is a funding strategy where increases in private land values generated by public investments are “captured” or recouped by the public sector.   Various permutations on value capture have been used to fund rail investments from Union Station in Denver to the Atlanta Beltline’s tax allocation district.   

The Wall Street Journal  ran a lengthy article on the increasing demand for transit oriented development.  Even in suburban areas, residential and commercial real estate markets are increasingly treating transit access as an attractive and potentially lucrative amenity.  As a result, transit access can be a strong driver for the location and form of redevelopment.

Both from the perpectives of value capture and transit oriented development, light rail along the US 41 corridor is the best option for the Cobb County transit project.  Unlike the alignment along I-75, the real estate along US 41 is developable (and ripe for redevelopment).  And light rail is the right mode for this corridor because, unlike bus service, light rail has a proven track record of stimulating transit oriented development all around the country.  This redevelopment in turn opens the door to value capture as a funding mechanism for the underlying project.  

Suburban Atlanta is often held up as a (negative) case study on how transportation projects drive development.  The Cobb County transit project is an opportunity for metro Atlanta to chart a different course and provide a positive example of this phenomenon as well.

Same Projects, Many Different Pie Graphs

The Sierra Club of Georgia created a stir when they announced their opposition to this summer’s regional transportation referendum.  They believe that too much of the money would be used for new road capacity, furthering metro Atlanta’s reliance on automobile travel and its sprawling development patterns. 

The TIA projects are set and defined.  But that doesn’t mean people see these projects the same way or even agree on which projects are  “new road capacity.”  The following graphs – from the Sierra Club, ARC, and GDOT respectively – all look at the same project list but they reach very different conclusions about what is in the list. 

Sierra Club's Categorization of TIA Projects

Two key differences are how much funding would be used for new road capacity and how to account for the 15% of TIA funds that would be set aside for local governments to use for local projects.  

In the the Sierra Club‘s graph,  34% of the project list would be used for “new roadway capacity” and the 15% local set aside is included in the road column based on the “expectation … that the bulk will be devoted to road proejcts.”

Atlanta Regional Commission's Categorization of Road Projects

GDOT's Project Categorization of TIA Projects

 The Atlanta Regional Commission  looks at the same project list and comes up with different numbers.  They exclude the 15% local set aside under the theory this money has not yet been allocated for specific projects.  And they offer more project purposes, such as  “Freight,” “Safety and Operations,” and “Asset Managment.” Correcting for the exclusion of the local set aside, ARC believes that only 19% of the TIA money will go toward road capacity projects.

 GDOT  offers yet a third view of these same projects.  They believe that 41% of TIA funds will be used for road capacity projects, divided between  road expansion in activity centers (20%) and other road expansion projects (21%).  This percentage is larger than Sierra Club’s and double ARC’s estimate.  GDOT’s $8 billion total includes the 15% local set aside, suggesting that they have already assigned these to-be-determined projects into specific categories.

So what does this all mean?  There are a couple take-aways here.  

  1. Metro Atlanta’s transportation needs are many and varied: repairing aging infrastructure, improving safety,  removing bottlenecks, and providing multimodal options.  The TIA is intended to make progress on all of these fronts.  
  2. One project can serve different needs.  If an undersized and deteriorating bridge is replaced with a larger one that can accomodate transit vehicles and pedestrians, can any one category accurately capture the project’s purpose?
  3. Different groups can look at the same projects and come to different conclusions based on their perspective, biases, and priorities. Given the diversity of stakeholders involved in this process, the fact that the list can be spun in so many different directions might mean the list gets the project mix about right.   

Penny for Your Thoughts but 60¢ for a Mile

The AJC reports that AAA has raised the estimated cost of driving to 60 cents per mile for an average sedan.  The complete study is here. This 2% increase from last year reflects several factors including “relatively large increases in fuel and tire costs.”

The AAA data shows that drivers of larger vehicles are hit even harder by the increasing price of gas, and the long distances Atlantans drive exacerbate these changes.  The following table illustrates the annual cost of owning and operating different vehicles based on the driving assumptions from the AJC (35 miles per day, 250 work days per year).

 But those numbers are averages; in the real world your annual transportation cost varies depending on where you live and work.  Some will commute longer than 35 miles and others will drive less.   But long distance commuters from exurban areas will be hit particularly hard by increases in the cost of driving, further eroding the viability of future growth in these areas.

Exurban growth has long been driven by the notion that these communities provide a more affordable housing option.  The saying was that you “drive until you qualify” for the house you want.  But this development pattern treats the cost of transportation as an externality – the cost of gasoline doesn’t count because it isn’t on your mortgage statement.  When you factor in the cost of transportation these far-flung homes look increasingly un-economical.

The Center for Neighborhood Technology’s Housing + Transportation Affordability Index addresses this problem by calculating the percent of household income spent on housing plus transportation.  They found that residents on the exurban fringe may spend less of their income on housing than their peers but these savings are more than offset by the larger amount spent on transportation.  The Housing and Transportation Affordability map of Atlanta can be found here.

And the fact that these are the same people that “drove until they qualified” may mean they are less equipped to deal with increasing transportation costs.  A 2% annual increase may not seem like a lot but if your budget is already streched thin and you are facing a long commute, increasing the cost of driving can be a real challenge.   

Taking this larger view, the AAA study represents another data point supporting the same conclusion: we need to rethink our model for growth and  invest in affordable transportation options throughout metro Atlanta.