Category Archives: Accessibility

Access Across America Pooled Fund Webinar

Access Across America is a state-of-the-art multimodal accessibility evaluation for transportation system performance management and planning. The webinar (recorded August 6, 2014) featured an overview of the Access Across America project and examples of accessibility calculation results, information about the request for participation in the Access Across America Pooled Fund project, and a question and answer session.

(Pooled Funds are the “Kickstarter” for transportation research, where participants are usually, but not only, state DOTs – notably this process was developed in transportation some 20 years ago, much earlier than Kickstarter formed … yet another example of transportation exporting technologies to other sectors).

Watch webinar


Pooled Fund Proposal Draft

Accessibility and the Allocation of Time: Changes in Travel Behavior 1990-2010

Recent working paper:

Brosnan, M and Levinson, D. (2014)  Accessibility and the Allocation of Time: Changes in Travel Behavior 1990-2010

Network Distance to CBD
Network Distance to CBD
  • Using detailed travel surveys conducted by the Metropolitan Council of the Minneapolis-St. Paul (Twin Cities) Region in Minnesota for 1990, 2000-2001, and 2010-2011, this paper conducts a detailed analysis of journey-to-work times, activity allocation and accessibility.  This study corroborates previous studies showing that accessibility is a significant factor in commute durations. Adjusting land use patterns to increase  the number of workers in job-rich areas and the number of jobs in labor-rich areas is a reliable way of reducing auto commute durations. The finding that accessibility and commute duration have a large affect on the amount of time spent at work shows that activity patterns are influenced by transportation and the urban environment in very impactful ways. The descriptive results of this analysis show a measurable decline in the time people spend outside of their homes as well as the amount of time people spend in travel over the past decade. Although trip distances per trip are not getting any shorter, the willingness to make those trip is declining, and as a result fewer kilometers are being traveled and less time on average is being allocated to travel.

Accessibility and the choice of network investments in the London Underground

Recent working paper:

Levinson, D., Giacomin, D., and Badsey-Ellis, A. (2014) Accessibility and the choice of network investments in the London Underground. Presented at the World Symposium on Transport and Land Use Research, June 2014, at Delft.

Accessibility in London in 1881
Accessibility in London in 1881



  • Abstract: In 1863, the Metropolitan Railway of what came to be known as the London Underground successfully opened as the world’s first subway. Its high ridership spawned interest in additional links. Entrepreneurs secured funding and then proposed new lines to Parliament for approval, though only a portion were actually approved. While putative rail barons may have conducted some economic analysis, the final decision lay with Parliament, which did not have available modern transportation economic or geographic analysis tools. How good were the decisions that Parliament made in approving Underground Lines? This paper explores the role accessibility played on the decision to approve or reject proposed early London Tube Schemes. It finds that maximizing accessibility to population (highly correlated with revenue and ridership) largely explains Parliamentary approvals and rejections.
    Keywords: Accessibility, Network Growth, Subways, Public Transport, Travel Behavior, Networks

Developing a Comprehensive US Transit Accessibility Database

Recent working paper:

Transit Accessibility in Minneapolis
Transit Accessibility in Minneapolis

Owen, A. and Levinson, D. (2014) Developing a Comprehensive US Transit Accessibility Database

  • This paper discusses the development of a national public transit accessibility evaluation framework, focusing on lessons learned, data source evaluation and selection, calculation methodology, and examples of accessibility evaluation results. In both practice and in research, accessibility evaluation remains experimental and methodologically fragmented. This heightens the “first mover” risk for agencies seeking to implement accessibility-based planning practices, as they must select a method which might produce results that can only be interpreted locally. Development of a common baseline accessibility metric could advance the use of accessibility- based planning. The accessibility evaluation framework described here builds on methods developed in earlier project, extended for use on a national scale and at the Census block level. Application on a national scale involves assembling and processing a comprehensive national database of public transit network topology and travel times. This database incorporates the significant computational advancement of calculating accessibility continuously for every minute within a departure time window of interest. Values for contiguous departure time spans can then be averaged or analyzed for variance over time. This significantly increases computational complexity, but provides a very robust representation of the interaction between transit service frequency and accessibility at multiple departure times.

Chicago Transit Accessibility 7–9 AM (Video)

Accessibility to jobs by transit for every Census block in the Chicago metropolitan area, between 7 and 9 AM. Based on CTA, Metra, and Pace schedules from January 2014.

Lighter colors indicate few jobs can be reached within 30 minutes; darker colors indicate more jobs can be reached within 30 minutes. At the highest levels, millions of jobs are accessibility by transit within 30 minutes. Travel times include walking, waiting, riding, and transfers.

Data sources: US Census Bureau, Chicago Transit Authority, Regional Transportation Authority, OpenStreetMap.

This is work of the University of Minnesota Accessibility Observatory.

Measuring Access

Big Data Week at Mississippi State University
Big Data Week at Mississippi State University

I visited Mississippi State University earlier this week as part of the Social Science Research Center‘s Big Data Week. I talked about Measuring Access, and our research as part of the Access to Destinations project and the new Accessibility Observatory.

The presentation can be viewed here (Keynote for iCloud).

I will be writing more about the Town of Starkville, Mississippi later.

Women work closer to home

Shomik  Mehndiratta and Tatiana Peralta Quiros from the World Bank write about Buenos Aires:
“[M]en and women’s average commuting times may be roughly the same, but men actually travel at significantly faster speeds and, as a consequence, cover larger distances. In general, trips made by women, particularly women with children were made at significantly lower travel speeds. (see table below: women with children, for instance, travel an average distance of 7.92km at an average speed of 9.98km/hr, as opposed to an average distance of 9.96km for men with children, which translates into a speed of 12.27km/hr).

Table 1
: Travel times, distances and speeds for work trips for men and women.
Work Trips. ENMODO 2009. Expanded Survey
Average Time (min) Average Distance (km) Average Speed (km/hr)
Women without Children 45.3 7.50 9.92
Men without Children 43.3 8.67 12.01
Women with Children 47.7 7.92 9.98
Men with Children 48.7 9.96 12.27

How can we explain those differences? Our hypothesis is that women’s travel choices are limited in part by household maintenance activities, which force them to rely on comparatively slower modes: the survey finds that women walk more than men and take buses, while men are using cars and trains more.

If women are indeed constrained to smaller commutes, it also means they have access to fewer employment opportunities – with inevitable consequences on their wage rates and related labor market outcomes. The map below highlights the stark contrast in job accessibility between men and women in the Buenos Aires Metropolitan Area: in parts of the city, men with children have access to over 80% more jobs than their female counterparts.”



This Map Wants to Change How You Think About Your Commute – Atlantic Cities

Our Accessibility Observatory is featured in nice, detailed article in Atlantic Cities by Emily Badger: This Map Wants to Change How You Think About Your Commute

Transit Accessibility for the Minneapolis St. Paul region from the Accessibility Observatory
Transit Accessibility for the Minneapolis St. Paul region from the Accessibility Observatory

“When we think about this as economists, we know that every trip that is made is worth it – the value outweighs the cost of taking it – or it wouldn’t have happened,” says Andrew Owen, the director of the recently created Accessibility Observatory at the University of Minnesota. “It’s a little bit disingenuous to use metrics that only talk about the cost of travel.”

Read the article for details. More maps coming soon.

Basic Employment vs. Sectors with Spillovers

Standard urban economics discusses Economic Base Theory. A nice definition is via Tim Chapin:

The economic base technique is grounded in the assumption that the local economy can be divided into two very general sectors: 1) a basic (or non-local) sector or 2) a non-basic (or local) sector.

Basic Sector: This sector is made up of local businesses (firms) that are entirely dependent upon external factors. For example, Boeing builds and sells large airplanes to companies and countries located throughout the world. Their business is dependent almost entirely upon non-local firms. Boeing does not sell planes to families or households locally, so their business is very much dependent upon exporting their goods. Manufacturing and local resource-oriented firms (like logging or mining) are usually considered to be basic sector firms because their fortunes depend largely upon non-local factors, they usually export their goods.

Non-basic Sector:The non-basic sector, in contrast, is composed of those firms that depend largely upon local business conditions. For example, a local grocery store sells its goods to local households, businesses, and individuals. Its clientele is locally based and, therefore, its products are consumed locally. Almost all local services (like drycleaners, restaurants, and drug stores) are identified as non-basic because they depend almost entirely on local factors.

Economic development practice is to entice/enhance “basic” industry. The example of Boeing is especially timely, given the recent issue of Boeing potentially moving airframe production if it didn’t get labor givebacks. I don’t imagine most of the places that Boeing was considering moving to have an airframe sector, or upstream or downstream vendors or customers, or a workforce skilled in airframe manufacturing, which would generate benefits beyond “jobs, jobs, jobs”. Similarly, ED advocates often argue for new infrastructure , despite at best weak evidence that in a mature (roadrailtransit) network there will be much accessibility gain, and thus little resulting economic development.

But the key point to remember from welfare economics is that everything is non-basic at a global level, and everything is basic at the household level. While it might be locally preferred to have more basic employment (we get money in exchange for stuff), that makes no difference on the global scale. Economic development practice is parochial (which is no surprise as it is funded by place-based local and state governments).

Yet that is not to say that local development is neither good nor bad. The reason it might actually be better to have local concentrations is because of various types of economies: in particular economies of scale of various kinds (including economies of agglomeration, which in places with very large employers, may all be internalized), and network economies. These economies produce spillovers, not just for the firm, but also for upstream and downstream supplies and customers, and potentially for competitors as well. I will call these Spillover Sectors.

Economies of scale mean that the cost goes down the more that is produced, (economies of scale are within firm, economies of agglomeration are within place, but between firms), so we can lower global costs if we specialize. The core reasons for this include large fixed costs associated with plants.

Reasons for Economies of agglomeration are also plentiful (from the Transportation Economics Wikibook):

Type of scale economy Example
Internal 1. Pecuniary Being able to purchase intermediate inputs at volume discounts
Technological 2. Static technological Falling average costs because of fixed costs of operating a plant
3. Dynamic technological Learning to operate a plant more efficiently over time
External or Agglomeration Localization Static 4. Shopping Shoppers are attracted to places where there are many sellers
5. Adam Smith Specialization Outsourcing allows both the upstream input suppliers and downstream firms to profit from productivity gains because of specialization
6. Marshall labor pooling Workers with industry-specific skills are attracted to a location where there is a greater concentration.a
Dynamic 7. Marshall-Arrow-Romer Learning-by-doing Reductions in costs that arise from repeated and continuous production activity over time and which spill over between firms in the same place
Urbanization Static 8. Jane Jacobs innovation The more that different things are done locally, the more opportunity there is for observing and adapting ideas from others
9. Marshall labor pooling Workers in an industry bring innovations to firms in other industries; similar to no. 6 above, but the benefit arises from the diversity of industries in one location.
10. Adam Smith division of labor Similar to no. 5 above, the main difference being that the division of labor is made possible by the existence of many different buying industries in the same place
Dynamic 11. Romer endogenous growth. The larger the market, the higher the profit; the more attractive the location to firms, the more jobs there are; the more labor pools there, the larger the market—and so on
12. Pure agglomeration Spreading fixed costs of infrastructure over more taxpayers; diseconomies arise from congestion and pollution

Source: World development report 2009: reshaping economic geography By World Bank, Adapted from Kilkenny, Maureen (1998) “Economies of Scale” Lecture for Economics 376, Rural, Urban, and Regional Economics, Iowa State University, Ames Iowa

Economies of scale are so pervasive we don’t notice them. Every road is an instance of economies of scale, we walk/ride/drive along roads because it is faster than going across unimproved space, even though it is less direct, but we individually could not afford to build the road, so we share the fixed costs with lots of people. The cost per person for roads is lower the more persons we spread the cost over. Economies of scale may also be played out (exhausted) at the margins we observe. Just because we had economies of scale in the roads we have built to date does not mean there are still economies of scale waiting to be picked up off the street like the proverbial $10 bill.

Two economists are walking down the street when one points to the ground and says, “Look, a ten dollar bill!”

The second economist replies, “That’s crazy. If that was a ten dollar bill someone would have picked it up already.”

In fact, most of the easy things have been done. Not to be as pessimistic as Tyler Cowan, but it is true that we pick the the projects with the highest Benefit/Cost ratios (low-hanging fruit) first, and work our way down-the list (up the tree), until the cost of building the project outweighs the benefits (the cost of getting the fruit outweighs the pleasures of consuming it). Clearly new projects are often on the low B/C side of the equation.

Network economies mean that the value of something increases the more people who use it. These are also so pervasive we don’t always notice them. The more people who use MSP airport, the better the airport is for me, because it will have more flights. Roads are also examples of network economies, as the more people who use the road, the higher quality road we will build and the more accessibility (by auto) I will have. Thus we have interstate highways because we have hundreds of millions of drivers. If there were only one driver, even Bill Gates, we would not have an interstate system.

So to get back to types of employment. When doing economic development we should not be thinking about Basic vs. Non-basic. We should be thinking about employment that has benefits from concentration, either economies of scale and agglomeration, or network externalities, or both, and then working toward establishing concentrations of those sectors to maximize the benefits to society.  This usually means considering where local strengths already are, rather than starting from scratch. Complement the existing rather than dropping in an alien business.  The job multiplier from two jobs paying $75,000 may be the same, but the one in a spillover sector will lower costs for others in the sector and/or improve benefits.  It means not going after projects just because they generate jobs, but encouraging firms to relocate into specialist concentrations where there are spillover benefits from those concentrations.

In contrast, sectors which have losses with concentration (think natural monopolies, where competitors split the market so that no firm can recover fixed costs), should be encouraged to remain dispersed.

RTA Transit Innovations Series

I will be talking, over the Internet, in Raleigh-Durham on January 8 about accessibility and transit at the RTA Transit Innovations Series.

The Regional Transportation Alliance has launched a new RTA Transit Innovations Series to support and advance current discussions on transit in Wake County.

The sessions include in person and/or videoconference presentations from experts on bus rapid transit and related innovations and research including express lanes, freeway caps, land use, circulators, and periodic comparisons with various rail transit options such as commuter rail, streetcars, and light rail.

    (Download pdf overview of the RTA Transit Innovations Series here).

With the exploration of new and emerging transit innovations, the development of a bus rapid transit-based alternative(s) as a basis for comparison with the current draft plan, and the clarification and prioritization of goals and objectives, our community can evaluate the potential mobility and economic benefits of transit for our community and make an informed decision on our enhanced regional transit future in Wake County.

There will be no cost to attend any of the events in the RTA Transit Innovations Series.  Scroll down or click here if you are interested in sponsoring either an individual session or the entire RTA Transit Innovations Series.

Detailed schedule of all past and future RTA Transit Innovations Series events.

Next Session
RTA Transit Innovations Series
Session 2:  Research on land use and tradeoffs

Wednesday, January 8, 2014, 3:30 pm EST
Greater Raleigh Chamber of Commerce


Presenters, via Cisco WebEx videoconference:                        

  • David Levinson, Ph.D., University of Minnesota
    –  Editor of the Journal of Transport and Land Use and Director of the NEXUS research group
  • Stephanie Lotshaw, Manager, U.S. and Africa, Institute for Transportation and Development Policy
    –  Author of More Development for your Transit Dollar 

RSVP online or contact by Monday, Jan. 6

Join the Conversation on Twitter @RTATriangle, and use the following tag:  #RTATransitSeries.