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.

Cross-posted from streets.mn: 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

by David Levinson on July 30, 2012 in Bridges

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 – Introduction, Part 2 – Structure, Part 3 – Communication, Part 4 – Politics, Part 5 – Economics, Part 6 – Traffic, Part 7 – Replacement, Part 8 – Policy Implications