We released Access Across America a little over a month ago. The following summarizes some discussion of the report.
Price Roads | Accessibility map:
"Excellent accessibility ranking by Dr. David Levinson (the Transportationist) and the Nexus Research Group at University of Minnesota:
California has the #1 and #2 most accessible cities, and they provide an interesting contrast in two ways to get accessibility. Accessibility can come from density (everything is close together so it doesn’t take long to go from one place to another) or mobility (everything is far apart but there are huge highways so you can traverse long distances).
I’m excited to see academics using visual media to put across point about public policy."
David Levinson, a transportation economist at the University of Minnesota, has emphasized that one of the key issues in infrastructure investment is improving accessibility, or the ease of reaching valued destinations. One way to improve accessibility is make it easier to traverse long distances, so you can reach a larger number of jobs and consumption opportunities, etc., in a given amount of travel time from home. Another way to improve accessibility is to bunch up jobs and consumption opportunities and homes, i.e., by increasing density. Levinson finds that while accessibility has deteriorated relative to 1990, it has improved relative to 2000. My sense is that the best way to increase accessibility is to focus on implementing peak road-user fees and using the resulting revenue stream to carefully add capacity at bottlenecks, and also to ease local land use regulations that have proven a barrier to increased density in high-productivity regions. These strategies ought to be pursued in tandem. One crude way of putting this is that while we tend to fixate on the “hardware” layer of infrastructure, we should devote more attention to the “software” layer, i.e., the systems governing the allocation of infrastructure resources. Focusing on accessibility rather than infrastructure spending levels as such will get us much closer to tackling the frustrations that plague commuters.
Robert Poole, Surface Transportation Newsletter #115: New Study Ranks Access to Jobs via Auto Commuting
New Study Ranks Access to Jobs via Auto Commuting
Transportation is not an end in itself; it's a means to other ends, such as getting to and from work. Taking this point to heart, a growing number of researchers in recent years have promoted the concept of "access" as being more important than speed or travel time, per se. One of the leaders in this field, David Levinson of the University of Minnesota, defines accessibility as "the number of destinations reachable within a given travel time" by a particular mode of transportation. He is the author of a new study called "Access Across America," released last month by U of M's Center for Transportation Studies.
In this study, Levinson estimated the accessibility to jobs by car for the 51 largest U.S. metro areas. His data are for 1990, 2000, and 2010, so in addition to providing a snapshot of conditions as of 2010, the data also allow him to document trends over the past two decades. The results may surprise many of those concerned about traffic congestion in the largest metro areas, because Levinson finds that the 10 metro areas that provide the greatest accessibility to jobs via auto commuting are, in order: Los Angeles, San Francisco, New York, Chicago, Minneapolis, San Jose, Washington, Dallas, Boston, and Houston. And over the past two decades, the places with the largest increases in accessibility by car are Las Vegas, Jacksonville, Austin, Orlando, and Phoenix. Those with the largest decreases are Cleveland, Detroit, Honolulu, and Los Angeles.
What accounts for these findings? Although Levinson doesn't really get into the details, I think one of the most important factors is the ongoing suburbanization of jobs. Remember, Levinson's data are for entire metro areas, and there has been a huge dispersion of jobs throughout these metros over the past 50 years. A good summary of the data was provided last month by Wendell Cox in "Job Dispersion in Major US Metropolitan Areas, 1960-2010." (www.newgeography.com/content/003663-job-dispersion-major-us-metropolitan-areas-1960-2010) For example, in 1960 54% of employment in 35 major metro areas was in the historical core municipalities—but by 2010, that figure had dropped to 30%, with 70% in suburban and exurban areas. The suburbanization of jobs has made huge numbers of workplaces more accessible by car than before, leading to shorter average work-trip travel times than in Canada or Europe.
Levinson's data show that in 31of the 51 metro areas, all the jobs can be reached by car in 30 minutes or less; upping the limit to 40 minutes brings the total to 39 of the 51, and at 60 minutes, almost everyone can reach nearly every job in every one of the 51 metro areas. That's pretty outstanding performance by the highway system, despite the existence of serious congestion.
It's instructive to contrast Levinson's auto accessibility figures with the findings of a Brookings Institution study from 2011 on accessibility to jobs via transit ("Missed Opportunity: Transit and Jobs in Metropolitan America"). Using a 45-minute transit commute time, that study found that only 7% of jobs could be reached, in the 100 largest metro areas. Even at 60 minutes, transit could get people to only 13% of the area's jobs. To reach 30% of the jobs, you need an average travel time of 90 minutes, which is more than three times the duration of the average U.S. auto commute.
Knowing this, some advocates of Smart Growth therefore disparage the suburbanization of employment as "jobs sprawl" and seek to promote public policies that would reverse it, so that transit could do a better job. But that confuses means with ends. If the purpose of an urban transportation system is accessibility, we should work to make the system serve that goal, not engage in a utopian quest to massively reshape the urban landscape. And, as I have written in previous issues of this newsletter, the implication for transit is to develop more flexible systems that can link more people cost-effectively to jobs. That argues for grid-based bus systems as opposed to radial bus and rail systems focused on what used to be the "central business district."
Angie Schmitt: A Better Way to Grade City Transportation Systems
A study recently released by the University of Minnesota presents an interesting alternative to the TTI’s metrics. UMN Transportation Engineering Professor David Levinson recently analyzed metropolitan commuting according to a very different criterion: accessibility, or “the ease of reaching desired destinations.”
Levinson attempted to improve on the TTI report by tracking the time it takes for people in the 51 largest U.S. metro areas to reach jobs. His findings stand in stark contrast to the TTI’s report. Large metros like Los Angeles, San Francisco, New York and Chicago offered the greatest number of jobs within a 10-minute car commute, Levinson found.
While TTI’s methodology penalizes cities for locating homes and businesses close together, because that increases congestion, in Levinson’s analysis, higher concentrations of destinations are rewarded for helping to reduce travel times.
“There are two ways for cities to improve accessibility—by making transportation faster and more direct or increasing the density of activities, such as locating jobs closer together and closer to workers,” Levinson writes.
“Accessibility is not a new idea,” he adds. But his is the first study that uses it to systematically attempts to measure how different metro areas compare. The report focuses only on auto access, but the same concepts could be applied to walking, biking, or transit access, he says.
To measure accessibility, Levinson factored in average job density, the average speed of car traffic in the transportation network (from the TTI analysis), and the circuity of trips (how indirect they are). The analysis also looked at the number of destinations within 10-, 20-, 30-, and 40-minute “donuts” around the city.
Levinson found that his measure of “accessibility” is linked to a number of positive economic indicators. For example, he found that home prices in a metro area increase 0.23 percent with every 1 percent increase in accessibility. He also found that doubling accessibility leads to a 6.5 percent increase in real average wages.
There are environmental and quality-of-life connections, as well. Levinson found that a 1 percent increase in accessibility is linked to a 0.06 percent reduction in the share of commuters who drive. He also found that accessibility tends to be linked to shorter overall commute times. A 1 percent increase in “accessibility,” he found, is correlated to a 90-second reduction in average commute time each way.
All of this suggests that prioritizing “accessibility” in transportation investment — rather than alleviating congestion – might be more economically beneficial for metro regions.
Levinson found that accessibility, or the ease of reaching important destinations, has declined in the United States over the past two decades. Image: University of Minnesota
Levinson also measured how accessibility has changed in metro areas over time, finding that it has worsened in American regions overall, both since 1990 and since 2000.
Some additional blog discussion below
Atlanta: JunctionATL Opening Our Eyes to Accessibility
Charlotte: PlanCharlotte: Easy access to work? Charlotte’s not atop list
Los Angeles: CurbedLA Real Study Found That LA is Best in the US For Car Commuting - The Commute
Los Angeles: Crikey Is Los Angeles the best US city for commuting?
NRDC Switchboard: 'Accessibility' trumps traffic:
Some other briefer mentions below
Los Angeles Transportation Headlines : LAX Transit Link, ONT Airport, LA2050, Access Across America, LA Bike Wars, LA Light Syncing, Port Railyard,
The Direct Transfer: Accessibility Ranked in 51 Metro Areas
reprinted at Sustainable Cities Collective
Minnesota Public Radio Study ranks Minneapolis-St. Paul #5 in accessibility to jobs by car in 2010
Drew Kerr Five for Five