Urban Mobility Report, Beyond the Executive Summary

Although its “Most Congested Cities” ranking garners all the press, the Urban Mobility Report contains a wealth of other transportation data.  Its numbers and methodology may differ slightly from those used by ARC or other planning entities but the duration of UMR‘s data – spanning over two decades – provides a unique opportunity for analyzing long term trends in the region.

Below are an assortment of graphs of the UMR data and observations about what it might be telling us.

Population to Drivers

Graph of Atlanta’s Growth in Population, Peak Period Drivers, and Commuters Over Time,

  • The growth in commuters has increased at a similar rate as the population at large.  The majority of peak period drivers are commuters but roughly half of the population are neither commuters nor peak period drivers.  In other words, only half of Atlantans are driving at rush hour.
VMT v Population

Growth in Atlanta’s Freeway and Arterial Driving Compared to its Population Growth

  • Unlike the number of drivers, the distance driven by Atlantans has not tracked population growth.  Instead, the distance driven has at times been greater and at other times been less than population growth. This ebb and flow is likely a result of many factors, including economy activity and the geographic location of growth during that particular period of time.
Congestion Costs

Change in Atlanta’s Total and Per Commuter Congestion Costs Over Time

  • Atlanta’s congestion costs, both total and per person, have dropped since their peak in the mid 2000s and prior to the recession in 2008.
  • Total congestions costs have begun to rebound recently but per commuter costs have remained flat.  This difference may suggest that the region’s population has grown more than its congestion costs over the past several years, spreading the congestion cost increase over a larger population base.
Percentage Experiencing Congestion

Change in the Percentage of Atlanta’s Roadways Experiencing Peak Period Congestion Over Time

  •  Although metro Atlanta’s population has continued to grow the percentage of its roadways experiencing rush hour congestion has remained relatively flat over the past decade.  This could demonstrate the existence of some maximum level of system congestion, where population growth leads to certain roads becoming more congested rather than more roads reaching the same level of congestion.
Atlanta's Transit Usage in Miles and Trips

Atlanta’s Transit Usage in Pasenger Miles and Trips

  • The distance Atlantans have traveled by transit has increased over time but the total number of trips has remained roughly the same. One possible explanation is that MARTA use has been reduced by several service cuts and fare increases over this period but commuter bus service through GRTA and other providers has increased to offset these reductions.  Trips by GRTA and other commuter services are longer in distance than those by MARTA, so this tradeoff would increase the distance traveled by transit but maintain a similar number of trips.

The UMR has a smaller data set related to the congestion costs and delay avoided due to transit service and operational improvements.  This information illustrates the role of transit and operation improvements in ameliorating travel conditions in the region.

Delay and Reductions by CategoryCost and Savings By Category

  • Compared to the total figures, transit and operational improvements may seem ineffective in avoiding costs and reducing delay.
  • However, these numbers must be understood in the context of the region’s modest transit service and vast roadway network.  The oft-cited (but problematic) statistic is that 4% of metro Atlantans use transit.  The UMR data shows that transit reduces the regional delay and congestion costs by 7-8%.  Rather than a one-to-one exchange of transit trips for delay and congestion costs, every transit trip has double the impact on regional congestion costs and delay.
  • It would be difficult to perform a similar comparison for the operational improvements but the percentage of the road network containing such improvements is likely far smaller than its impact in reducing delay and congestion costs.





Where the Artists Are (the Remix)

In a post on the Atlantic Cities blog, urban scholar Richard Florida uses data from the American Community Survey to explore the geography of class within metro Atlanta.

Naturally the “class” of particular interest to him is the so-called “creative class” (a term he coined) relative to the region’s service and working classes.  Florida defines the creative class as “people who work in science and technology, business and management, arts, culture, media, and entertainment, law and healthcare professions.”  This category covers “36.3 percent of the metro’s workers (above the national average of 32.6 percent).”

Florida’s blog post provides a compliment to ARC’s July 2012 Regional Snapshot on the same subject.  The two studies differ slightly in their granularity and definition of creative class (as well as their relationship with the north/south axis), but they reach similar conclusions about the geographic distribution of different types of jobs in the region.

Richard Florida’s Mapping of Metro Atlanta’s Creative Class

ARC's Mapping of Metro Atlanta's Creative Class

ARC’s Mapping of Metro Atlanta’s Creative Class

HSR in the General Assembly

The proposed amendment to the MARTA Act has received much of the attention this session, but two other bills have been introduced in the General Assembly that also could influence future passenger rail service in Georgia.

HB 306 would create and empower a new state entity, the Piedmont Altamaha Rail Authority, to provide higher-speed rail and other transit service between Bibb, Butts, Clayton, Henry and Monroe Counties.

HR 174 would create a House Study Committee on Atlanta-Savannah High Speed Rail to examine “the conditions, needs, and issues” related to high speed rail between the cities and recommend any necessary action or legislation.

Both bills have their shortcomings.  The rail entity created by HB 306 is too limited in funding and geographic scope, and its failure to connect to the urban core of metro Atlanta is glaring.  The study committee created by HR 174 appears to duplicate Georgia DOT’s work on the feasibility of a high speed rail between Atlanta to Savannah.

Whether from Atlanta to Macon, Savannah or anywhere else, the General Assembly will need to be on board for Georgia to make a meaningful investment in high speed rail.  Perhaps these bills are the first steps in that direction.

The Problem With Congestion (Rankings)

This week the Texas Transportation Institute released its annual transportation assessment, the Urban Mobility Report.  The study compares transportation data for urban areas around the country, focusing in particular on roadway congestion and the negative consequences that flow from it (lost time, increased cost, wasted gasoline, additional CO2 emitted).  The AJC ran their annual article discussing how metro Atlanta fared, highlighting the UMR‘s new trip reliability ranking and Georgia’s use of technology to improve its performance in this respect. WABEWSB and others also covered the rankings.

Criticism of the UMR, its rankings and its methodology are nothing new.  This most recent version was covered and criticized by Slate, Transportation Nation, the Atlantic, and Streetsblog.  But the group CEOs for Cities has undertaken the most comprehensive examination of the UMR, publishing an entire report in 2010 examining the study and its singular focus on congestion.  They also take the UMR to task for failing to account for travel distance in its analysis.  Ignoring distance, CEOs for Cities argues, “universally rewards cities that are spread out as opposed to compact urban areas.”

Larger, urban cities have traditionally fare poorly in the UMR and this year is no different, with Washington, DC, Los Angeles, San Francisco, New York and Boston topping the list.  Where trips are long and the automobile is the predominant means of travel, congested roads might be legitimately equated with poor transportation performance.  But in cities like Washington DC, New York, Boston and Chicago, where trips are often shorter and non-driving options are available, UMR’s congestion analysis is a poor reflection of actual transportation performance.

To illustrate this point, CEOs for Cities offers the infographic below comparing Charlotte and Chicago.  Although Chicago may have a worse travel time index (the UMR‘s measure of congestion),  Charlotte’s longer trip lengths mean its citizens spend more time traveling.

CEOs for Cities Comparison of Travel in Chicago and Charlotte.

CEOs for Cities’ Comparison of Travel in Chicago and Charlotte.

Matthew Yglesias’s article on Slate uses an economist’s lens to further elaborate on the shortcomings of the UMR‘s congestion focus.  First, congested roadways are a byproduct of economic activity and urban vitality.  The UMR‘s most congested cities are all growing, thriving, economically vibrant cities. Stagnant cities suffer from many problems, but usually not traffic jams. (Despite its large population and auto-centric culture, Detroit came in 40th in the rankings).

Second, congestion is necessary for supply and demand forces to calibrate the optimal use of our roadway resources.  The majority of our roads are free, which allows for drivers to “overconsume” until some “cost” imposed on their driving.  This cost often comes in the form of congestion.  Congestion forces drivers to evaluate when, where and how much they need to drive, reducing overconsumption and achieving a more optimal use of our roads.

UMR is a valuable tool for assessing transportation performance, particularly because of its city to city and year to year comparisons. But it also guilty of oversimplification and treating congestion as the problem, rather than a symptom. As the report itself admits, “there is no single performance measure that experts agree ‘says it all.’”