Call for Papers: Special Issue of Economics of Transportation in Honor of Herbert Mohring

Call for Papers
Special Issue of Economics of Transportation
in Honor of Herbert Mohring
Economics of Transportation, the journal of the International Transportation Economics Association, invites papers for a special issue in honor of Herbert Mohring, who passed away on June 4, 2012. All submissions will go through a regular peer review process. Papers submitted to the special issue can be on any topic in transportation economics. Papers on topics related to Mohring’s work are especially desirable. Mohring is best known for his work on transportation economics themes such as efficient pricing and capacity provision and the resulting implications for self-financing, and scale economies in public transport.
The special issue will be guest-edited by Marvin Kraus of Boston College ( To submit a paper, visit and indicate that your submission is for the Special Issue in Honor of Herbert Mohring. Any questions or problems should be directed to the guest editor.
Timetable for Submissions
* Deadline for initial submission of papers: February 1, 2013
* First-round referee reports returned to authors by May 15, 2013
* Deadline for submitting revised papers: September 1, 2013
* Second-round referee reports returned to authors by December 1, 2013.
* Deadline for submitting final drafts of papers: December 31, 2013
* Expected publication: Early 2014

Call of Papers: Spatial and Land Use Implications of Taxis, Jitneys, Paratransit and Flexible Transportation

David King of Getting from here to there will be editing a Special Issue of JTLU on “Spatial and Land Use Implications of Taxis, Jitneys, Paratransit and Flexible Transportation”. If you are doing research in the field, contact him.

Positions: Shanjiang Zhu -> George Mason

Nexus alumnus, Shanjiang Zhu was just appointed to an assistant professor position at the Civil, Environmental, and Infrastructure Engineering Department in the Volgenau School of Engineering at George Mason University.

CEIE Welcomes Dr. Shanjiang Zhu | GMU CEIE:

The CEIE Department is pleased to welcome Dr. Shanjiang Zhu to the CEIE Department in August 2012. Dr. Zhu obtained his doctorate from the Department of Civil Engineering, University of Minnesota, in 2010, and extended his research in transportation planning and engineering as a research scientist at University of Maryland for two years. His research interests include agent-based travel demand models, integrated models of micro-simulation and macroscopic demand models, applications of GIS/GPS in transportation modeling, sustainable transportation, and transportation economics. He enhances the current curricula by integrating problem-oriented teaching philosophy with his research experience in various transportation-related projects, especially those with immediate applications in addressing local transportation problems. Dr. Zhu is currently teaching the Introduction to Transportation Engineering (CEIE 360). He looks forward to working with CEIE students both in the classroom and on transportation-related research projects.”

The Fall and Rise of the I-35W Mississippi River Bridge – Part 7: Replacement |

Cross-posted from The Fall and Rise of the I-35W Mississippi River Bridge – Part 7: Replacement


The Fall and Rise of the I-35W Mississippi River Bridge – Part 7: Replacement


The replacement bridge cost $251 million, funded almost entirely by federal government. We can debate whether the federal government should have paid for it (it was originally built with 90 percent federal contributions, 10 percent state, but matches recently are much more balanced), since most traffic using the Bridge both originated in and is destined for Minnesota. With Minnesota Congressman James Oberstar then Chair of the House Transportation Committee, there was plenty of political support behind this.

The replacement bridge was hurried, completed by September 2008, several months ahead of the original schedule. This is good, a lack of a bridge costs the economy. (Xie and Levinson estimated between $127,000 and $170,000 per day, MnDOT estimated $400,000 per day). The contractor received $200,000 per day bonus for early completion. So perhaps in an economic sense, too much was paid to complete it a few months early.

Rebuilding a collapsed bridge is of course a crisis, but it is also an opportunity to do something interesting. Rushing designs may mean that ideas are missed. What was built is a functional bridge, and there are state-of-the-art real-time structural health monitoring systems installed, so I have no fear driving over it. It was also ensured that the Bridge would be compatible with any future light-rail transit lines, though none are planned for this bridge (and how they would transition from the center of the Bridge to any reasonable destination is extremely unclear). But could more have been done?

The snow removal and icing problem was not considered. Minnesota is famous for its winters. The previous I-35W bridge had installed a de-icing system (in response to earlier crashes), which had been speculated to be responsible for corrosion of the structure. While the NTSB did not find that, de-icing chemicals do have environmental consequences.

A solution not considered was air rights. A bridge over the Mississippi is expensive. But imagine having a 2 or 3 story office building hanging from below, and/or built above the highway. The views from the River are fantastic. It will not impair other views of the river especially much, and would generate a significant amount of revenue to pay for reconstruction. One example would be the historic London Bridge, which had houses and stores along the side, encroaching on travelways. There are better ways to combine transportation arteries with development opportunities, and creative design can show the way.

Why did we not build a habitable structure above the road deck, so that offices, residences, hotels, etc. could share the view? It would have increased the profile of the Bridge by two stories, but created an enormous amount of leasable space, leases which could have paid for themselves and the Bridge. Obviously it would increase the initial construction cost, and perhaps time, but that would be amply repaid over the long-term. That structure would further have shielded the roadway from ice and snow, reducing road snow clearance costs and crashes.

The bridge opened in the early darkness of September 18, 2008. A parade of first responders, and then a bulge of traffic all hoping to be the first (and none succeeding) went across. Soon the Bridge was attracting 120,000 vehicles per day, measurably off the pre-collapse levels.


Other Parts in Series: Part 1 – IntroductionPart 2 – StructurePart 3 – CommunicationPart 4 – PoliticsPart 5 – EconomicsPart 6 – TrafficPart 7 – ReplacementPart 8 – Policy Implications

Positions: Nebiyou Tilahun -> University of Illinois at Chicago

Nexus alumnus, and new father, Nebiyou Tilahun was recently appointed to an assistant professor position at the University of Illinois at Chicago:

Dr. Tilahun is currently an Assistant Professor in the Department of Urban Planning and Policy at the University of Illinois at Chicago. He received his Ph.D. from the University of Minnesota in 2010. His research interests are in transportation planning, travel behavior, the study of travel for social activities, and the use of agent based models for transportation planning applications. His dissertation, Matching Home and Work: Job Search, Contacts and Travel, developed a framework for work trip distribution from the perspective of the job search process. Between May 2009 and December 2011, he successively held postdoctoral researcher positions at the Urban Transportation Center (UIC) and the Hubert Humphrey School of Public Affairs (UMN) working on issues related to Job Access and Reverse Commute and Human Services Transportation (at UIC), and linking transit accessibility to the regional economy in the Twin Cities (at UMN). As a graduate student he was a member of the NeXuS research group. Previously he also worked as a Transportation Engineer at the Washington State Department of Transportation (2001-2002). Dr. Tilahun’s Civil Engineering studies started in Ethiopia at Addis Ababa University’s Faculty of Technology. During the Fall of 2012 he will be teaching UPP 502 Planning Skills: Computers, Methods and Communications and UPP 562: Urban Transportation III: Laboratory.

The Fall and Rise of the I-35W Mississippi River Bridge – Part 6: Traffic |

Cross-posted from The Fall and Rise of the I-35W Mississippi River Bridge – Part 6: Traffic

The Fall and Rise of the I-35W Mississippi River Bridge – Part 6: Traffic


Travel behavior changes after network disruption as well as after the replacement of disrupted links are not well-understood. The first table shows the number of river crossing trips by type of facility before and after the collapse and the reopening.

We discover 46,000 lost trips daily after the collapse (nearly a third of what the I-35W Bridge had carried), and 20,000 found trips after the new bridge opened. Those lost trips may not have been made, or more likely, found different destinations not requiring a river crossing. This provides additional evidence to the phenomenon of induced demand.

Bridge Collapses: 1-Aug-2007 Bridge Reopens: 18-Sep-2008
Bridge Before After Change Before Reopen After Reopen Change
I-35W 140000 0 -100.00% 0 120349
Arterial total 152311 197566 29.70% 169983 95895 -43.60%
Freeway total 572274 481040 -15.90% 488717 583127 19.30%
Total 724585 678606 -6.30% 658700 679022 3.10%


Gains from the Bridge for three peak periods re-estimated with accurate (observed) travel times (but fixed and not-observed OD matrix), shown in the second Table, were on the order of $70,000 per day (somewhat below our initial low all-day estimates ($127,000), far below Mn/DOT’s, and also below the contractor early completion bonus). Much of that gain is lost once the I-94 bridge lane disappears, as consistent with the original results. $42,000 annualizes to about $15 million in benefit, for a $250 million dollar bridge (which pays off in about 23 years at 3% interest). The I-94 lane restriping paid off in a matter of a month.


Other Parts in Series: Part 1 – IntroductionPart 2 – StructurePart 3 – CommunicationPart 4 – PoliticsPart 5 – EconomicsPart 6 – TrafficPart 7 – ReplacementPart 8 – Policy Implications

The Fall and Rise of the I-35W Mississippi River Bridge – Part 5: Economics |

Cross-posted from The Fall and Rise of the I-35W Mississippi River Bridge – Part 5: Economics

The Fall and Rise of the I-35W Mississippi River Bridge – Part 5: Economics


At the request of Mn/DOT, shortly after the collapse, Feng Xie and I estimated the Twin Cities 7-county region daily vehicle hours of travel with and without the Bridge using a planning model under two assumptions. The first kept the trip table fixed. This means that people did not change the number of trips, or destinations, in response to the Bridge failure. This should give an upper bound to the effects of the Bridge failure. The second allowed trip destinations to vary (though keeping the number of trips fixed). This provides more of a lower bound of the effects. Clearly some people can switch destinations, or avoid trips altogether, if the cost of their previous destinations are now too high. On the other hand, not everyone can do so. The exact number of people who change destinations is not something we can easily know.

Note, these are direct model outputs, so while the precision is high, the accuracy is not nearly as high as implied by the precision. We monetize these numbers using values of time from MnDOT (The current MnDOT values of time can be found here, a the time the values given were Auto $12.63/hour and Truck $20.41 and we assumed 80 percent auto and 20 percent truck giving a composite value of time of $14.19).

I believe the OIM Value of Time for Trucks is very low, our estimates (Smalkoski, Brian, and David Levinson (2005) Value of Time for Commercial Vehicle OperatorsJournal of the Transportation Research Forum. 44:1 89-102.) put the number at closer to $50 per hour. If we used that, we would get a composite value of time of $20.14.

The results in Table below are of course estimates. However, the number is large and positive, which we expect. And the numbers lead us to conclude that letting bridges fall down is bad public policy. Which most of us already knew. The number does have uses aside from (rhetorically) beating people over the head, it tells us, for instance, how much we should reward contractors for early completion.

The problem is that those who benefit from the Bridge (or lose from the absence of the Bridge) differ from those who pay for it, and are responsible for maintaining it. If presented with the choice of paying and keeping the Bridge up and not paying and letting it fall, most users would have gladly paid more than was required to keep the Bridge up.

Scenario Time Trip Table Planning Network
0 (Base) Before N.A. Complete network
1 After Variable Crippled network
2 After Fixed Crippled network
3 After Variable Crippled network with upgrades
4 After Fixed Crippled network with upgrades


VHT Fixed Trip Table Variable Trip Table
with 1,122,342
without 1,134,355 1,131,322
loss 12,013 8,980
Value $/day $170,425 $127,390

We conducted a more thorough analysis later (Xie, Feng and David Levinson (2008)Evaluating the Effects of I-35W Bridge Collapse on Road-Users in the Twin Cities Metropolitan RegionTransportation Planning and Technology 34(7) pp. 691-703.), considering upgrades to alternative routes, such as restriping I-94 to add a lane and upgrading Mn280, with somewhat lower results.

Scenario 0 Scenario 1 Scenario 2 Scenario 3 Scenario 4
Daily VHT (10^6 veh.hrs) 1.427 1.432 (0.35%) 1.442 (1.09%) 1.431 (0.31%) 1.441 (1.00%)
Daily VKT (10^6 veh.kms) 86.53 86.27 (-0.31%) 86.58 (0.05%) 86.27 (-0.30%) 86.58 (0.06%)
Daily Economic loss ($) N.A. 71,466 220,198 62,408 203,409
Ave trip length (kms) 18.82 18.76 (-0.31%) 18.83 (0.05%) 18.76 (-0.30%) 18.83 (0.06%)
Ave trip time (mins) 18.61 18.68 (0.35%) 18.82 (1.09%) 18.67 (0.31%) 18.8 (1.00%)


Other Parts in Series: Part 1 – IntroductionPart 2 – StructurePart 3 – CommunicationPart 4 – PoliticsPart 5 – EconomicsPart 6 – TrafficPart 7 – ReplacementPart 8 – Policy Implications

The Fall and Rise of the I-35W Mississippi River Bridge – Part 4: Politics

Cross-posted from The Fall and Rise of the I-35W Mississippi River Bridge – Part 4: Politics


The Fall and Rise of the I-35W Mississippi River Bridge – Part 4: Politics


Some will say the Bridge collapse was not about money. Throwing money at the Bridge would not have kept it from falling. Others note money could have bought:

  • more inspections,
  • a structural (e.g. finite-element) model of the Bridge,
  • better, faster repairs,
  • the ability to replace the Bridge sooner.

Money could have been spent more wisely. More importantly, money is always a constraint on decision-making at MnDOT. As was noted in the Star Tribune: “Phone call put brakes on bridge repair: Plans to reinforce the Bridge were well underway when the project came to a screeching halt in January amid concerns about safety and cost.” (Article by Tony Kennedy and Paul McEnroe, Star Tribune staff writers Last update: August 18, 2007 – 4:36 PM)

Tim Pawlenty had already vetoed a legislature-passed increase in the gas tax that could have raised money to repair bridges like this one. The latest vetoed gas tax would not have solved this problem, but previous taxes that were not passed (due in part to Pawlenty’s previous veto threat) may have, had the money been spent on this kind of thing. The gas tax had not been raised in Minnesota since 1988, and thus its purchasing power had diminished significantly, while the network was expanded and aged, and traffic levels increased. Pawlenty’s campaign took pride in this veto, posting a clipping from the Star Tribune on their website:

“WEDNESDAY, MAY 16, 2007
STAR TRIBUNE: Pawlenty vetoes gas tax, income tax bills

By Patricia Lopez, Star Tribune — Gov. Tim Pawlenty struck swiftly and with strong language Tuesday to veto a gasoline tax increase and an income-tax-for-property-tax swap that were at the heart of the DFL’s agenda for the session. — DFLers accused him of protecting the state’s richest 1 percent — those who would have borne most of the income tax increase, which would pay for the proposed property tax relief — at the expense of everyone else. But they conceded that some of their top objectives are fast sliding out of reach.”

PO BOX 21887 – EAGAN, MN 55121. (This article can still be accessed. Accessed April 19, 2012)

Gas Taxes in the United States and Minnesota are dedicated to transportation (and in some cases just to roads). The 2008 Minnesota gas tax bill phased in an increase of the gas tax by 8 1/2 cents a gallon by 2014. Of that, 3 1/2 cents of the gas tax increase was dedicated to paying the debt service on $2 billion in road and bridge bonds. The bill borrowed $1 billion from 2009-2010, with $600 million earmarked for repairing or replacing the state’s 13 most dangerous bridges. In addition, the bill increased the sales tax in the seven-county metro area by 0.25 percent for transit. It also increased license tab fees on newly purchased cars and trucks (1.25 percent on sale of new cars, drops 10 percent per year).

The bill was passed by the legislature, but vetoed by Governor Tim Pawlenty. The Governor had run on a “no new taxes” pledge, and clearly had political aspirations. He was frequently mentioned as a possible Vice Presidential running mate for the 2008 GOP Presidential Nominee, John McCain, and was hosting the GOP convention in St. Paul, Minnesota that year. While in the event, the Governor of Alaska, who had more foreign policy experience, got the nod as the VP candidate, Pawlenty continued to look towards higher office, and was for a time, a candidate in the 2012 GOP party nominating process, before dropping out for lack of support and will.

The Override Six are Republicans who voted with DFL to override Gov. Pawlenty’s veto of the gas tax bill. Four of them lost their seats due to Primary challenges, while the Republicans lost two of those seats to the DFL in the 2008 General Election. This leads to the rule that voting in favor of a gas tax increase can be dangerous to your political health, if you are a Republican.

  • Representative (District) – Party Endorsement? – Primary Victor – General Election Victor
  • Bud Heidgerken (13A-Freeport) – retired – – Paul Anderson (R)
  • Rod Hamilton (22B-Mountain Lake) – Rod Hamilton – Rod Hamilton – Rod Hamilton (R)
  • Ron Erhardt (41A-Edina) – Keith Downley – Keith Downley – Keith Downley (R)
  • Neil Peterson (41B-Bloomington) – Jan Schneider – Jan Schneider – Paul Rosenthal (DFL)
  • Jim Abeler (48B-Anoka)- no endorsement – Jim Abeler – Jim Abeler (R)
  • Kathy Tingelstad (49B-Andover) – retired – – Jerry Newton (DFL)

Carol Molnau was the state’s Lieutenant Governor and the MnDOT Commissioner. While she had been confirmed in the first Pawlenty Administration, when she was reappointed, the DFL legislature did not confirm her, and her appointment expired in February 2008. That can be directly tied with dissatisfaction with her and the Governor’s performance dealing with the Bridge. Notably she was not the Department’s point person with the media in days, weeks, and months following the collapse. She was replaced by Tom Sorel, a federal civil servant who had worked on the Bridge replacement process.

The political problem is deeper than just the fate of a few politicians though. It is a classic problem in transportation funding. Ribbon cuttings on new projects are much more attractive to politicians (and newspapers and TV news) than maintaining what we have. People are also more interested in road surface than the underlying structure. Yet pavement failure, while bad, is not nearly as bad as structural failure. “Failure” in the traffic level of service sense (LOS “F”), while economically costly and personally annoying, and perhaps leading to more (or at least different) crashes, does not have anywhere near the same connotation as structural collapse.

The competing uses of funds are ultimately political decisions. Should money be spent for bread and circuses (er. football and baseball stadiums) rather than genuinely productive infrastructure? Five years later, should money be spent on new bridges with added capacity (e.g. the Saint Croix River Crossing in Stillwater) while over 1000 structurally deficient bridges remain in Minnesota (Kimball, Joe (2011) MinnPost, Report says 1,149 Minnesota bridges are deficient)?


Other Parts in Series: Part 1 – IntroductionPart 2 – StructurePart 3 – CommunicationPart 4 – PoliticsPart 5 – EconomicsPart 6 – TrafficPart 7 – ReplacementPart 8 – Policy Implications

The Fall and Rise of the I-35W Mississippi River Bridge – Part 3: Communication |

Cross-posted from The Fall and Rise of the I-35W Mississippi River Bridge – Part 3: Communication


The Fall and Rise of the I-35W Mississippi River Bridge – Part 3: Communication

The I-35W Bridge collapse occurred before the advent of Twitter, when there were only 50 million users of Facebook (as February 2012 there were 845 million users, and growth in user numbers seems to be leveling off). [I joined Facebook on November 13, 2004, so they tell me, when Facebook had fewer than 1 million users (Facebook User Growth Chart by Ben Foster)], but it was pretty much useless to me until late 2008 when enough people I knew were on to make it interesting to check in. And though I added 24 “friends” in 2007, I never posted. It did not even occur to me to update my Facebook status, which would likely be the first place many Twin Citians would go today in such an event. I did update my blog the next day.

Yet the news traveled fast. TV, radio, on-road variable message signs, phone calls, emails, all helped transmit this knowledge. We have evidence on how the news traveled by looking at traffic counts. The figure below shows the difference in counts between August 1 and a week earlier, July 25, which are otherwise similar days. As noted, behavior changed quickly that night, traffic counts were lower systemwide, but especially upstream and downstream of the collapse. In contrast the best long distance alternatives (Mn100 and I-35E saw upticks in traffic).



Other Parts in Series: Part 1 – IntroductionPart 2 – StructurePart 3 – CommunicationPart 4 – PoliticsPart 5 – EconomicsPart 6 – TrafficPart 7 – ReplacementPart 8 – Policy Implications