Kara M. Kockelman, Ph.D., P.E.

EDUCATIONAL BACKGROUND

• Ph.D., 1998, The University of California at Berkeley, Civil Engineering
• M.S., 1996, The University of California at Berkeley, Civil Engineering
• M.C.P., 1996, The University of California at Berkeley, City and Regional Planning
• B.S., 1991, The University of California at Berkeley, Civil Engineering

GENERAL

Curriculum Vitae

          My Terrific Graduate Students

 

RESEARCH PAPERS (pre-prints & conference copies)

Roadway Pricing (including credit-based congestion pricing, welfare estimates & land use effects)

Land Use-Transportation-Trade Models (spatial econometrics, multiregional models, home choice, uncertainty propagation)

Travel Demand (Roy's Identity, land use relationships, long-distance travel)

Property Valuation (homes & businesses, vis-a-vis locational accessibility)

Traffic Safety (crash analysis: count, severity, frequency models)

Vehicle Distinctions (light-duty trucks, SUVs, ownership, external costs)

Traffic Flow (flow-density relationships by vehicle type, approximate dynamic traffic assignment)

Other Research (carbon emissions, economic impacts of bypasses, state-local coordination, sidewalk cross-sloping)

Go Top

• Credit-Based Congestion Pricing: A Dallas-Fort Worth Application

Transport Policy 15 (1): 23-32 (2008), and Proceedings of the 85th Annual Meeting of the Transportation Research Board (2006). With Pradeep Gulipalli. (Also, see UT News Story.)

 

• Congestion Pricing under Operational, Supply-Side Uncertainty

Under review for presentation at the 88th Annual Meeting of the Transportation Research Board and for publication in Transportation Research Part C. (2008) With Stephen Boyles and Travis Waller.

 

• Road Pricing Simulations: Traffic, Land Use and Welfare Impacts for Austin, Texas

Transportation Planning & Technology 29 (1): 1-23 (2006) With Surabhi Gupta and Sukumar Kalmanje. 

 

• The Financing of New Highways: Opportunities for Welfare Analysis and Credit-Based Congestion Pricing

  Under review for publication in Transportation Research Part B & presentation at the 88th Annual Meeting of the Transportation Research Board (2009). With Jason Lemp.

   

• Credit-Based Congestion Pricing: Expert Expectations and Guidelines for Application

Proceedings of the 84th Annual Meeting of the Transportation Research Board (2005) and forthcoming in J of the Transportation Research Forum. With Pradeep Gulipalli and Sukumar Kalmanje. 

 

• Congestion Pricing Technologies: Synthesis and an Evaluation Framework

Proceedings of the 84th Annual Meeting of the Transportation Research Board (2005), and Chapter 4 in New Transportation Research Progress (pp. 121-142), Filip Gustavsson (Ed.), Nova Publishers (2007). With Satish Ukkusuri, Ampol Karoonsoontawong, and S. Travis Waller. 

 

• Credit-Based Congestion Pricing: Travel, Land Value, & Welfare Impacts

Transportation Research Record No. 1864: 45-53 (2004). With Sukumar Kalmanje.

 

• Credit-Based Congestion Pricing: A Proposed Policy and the Public's Response

Transportation Research 39A: 671-690 (2005). With Sukumar Kalmanje. Also: Presentation to City of Austin & TxDOT Turnpike Authority & copy of On-line Survey.

 

• On-Line Marginal Cost Pricing across Networks: Incorporating Heterogeneous Users & Stochastic Equilibrium

Transportation Research 40B (5): 424-435 (2006). With Yong Zhao.

 

• Congestion Pricing & Roadspace Rationing: An Application to the San Francisco Bay Bridge Corridor

  Transportation Research 36A (5): 403-417 (2002). With Katsuhiko Nakamura.

• Toll Roads in Texas: Traffic and Welfare Impacts

Under consideration for publication in Journal of the Transportation Research Forum. (2006) With Sukumar Kalmanje. 

 

• Public Perceptions of Toll Roads: A Survey of the Texas Perspective

Transportation Research 40A: 888-902 (2006). With Kaethe Podgorski. 

 

• Public Perceptions of Pricing Existing Roads and Other Transportation Policies: The Texas Perspective

Proceedings of the 85th Annual Meeting of the Transportation Research Board (2006), and forthcoming in Journal of the Transportation Research Forum. With Kaethe Podgorski, Michelle Bina, and Shashank Gadda. * On-line survey * at http://www.tollroads.hypermart.net/.

 

• A Cordon Charge for the District of Columbia: A Solution to DC's Fiscal Problems and the Region's Congestion?

  Proceedings of the 86th Annual Meeting of the Transportation Research Board (2007). With Alexander Marks.

   

• A Simulation-based Approximation Algorithm for Dynamic Marginal Cost Pricing

  Proceedings the 87th Annual Meeting of the Transportation Research Board, in Washington D.C. (2008) and under review for publication in J of the Transport Research Forum. With Ampol Karoonsoontawong, Satish Ukkusuri, and S. Travis Waller. 

Go Top

RESEARCH: Land Use-Transportation-Trade Models

• Application of the Dynamic Spatial Ordered Probit Model: Patterns of Land Development Change in Austin, Texas 

  Presented at the 54th North American Regional Science Association International (RSAI) Conference, Savannah, Georgia (2007), and under review for publication in Papers in Regional Science. With Xiaokun (Cara) Wang.

   

• The Dynamic Spatial Ordered Probit Model: Methods for Capturing Patterns of Spatial and Temporal Autocorrelation in Ordered Response Data, using Bayesian Estimation 

  Presented at the 54th North American Regional Science Association International (RSAI) Conference, Savannah, Georgia (2007), and under review for publication in Journal of Regional Science. With Xiaokun (Cara) Wang.

   

• Specification and Estimation of a Spatially and Temporally Autocorrelated Seemingly Unrelated Regression Model: Application to Crash Rates in China  

  Transportation 34 (3): 281-300 (2007). With Xiaokun (Cara) Wang.

   

• Predicting the Distribution of Households and Employment: A Seemingly Unrelated Regression Model with Two Spatial Processes

  Proceedings of the 86th Annual Meeting of the Transportation Research Board (2007), and under review for publication in Journal of Transport Geography. With Brenda (Bin) Zhou.  

   

• Tracking Land Cover Change in a Mixed Logit Model: Recognizing Temporal and Spatial Effects

  Transportation Research Record No. 1977:112-120 (2006) With Xiaokun (Cara) Wang.  

   

• Neighborhood Impacts on Land Use Change: A Multinomial Logit Model of Spatial Relationships

Annals of Regional Science 42 (2): 321-340 (2008), and presented at the 52nd North American Regional Science Association International (RSAI) Conference, Las Vegas, Nevada (2005). With Bin (Brenda) Zhou.  

 

• Tracking the Size, Location and Interactions of Businesses: Microsimulation of Firm Behavior in Austin, Texas

  Proceedings the 87th Annual Meeting of the Transportation Research Board, in Washington D.C. (2008) and forthcoming in Transportation Research Record. With Saurabh Kumar. 

   

• Microsimulation of Single-family Residential Land Use for Market Equilibria

Presented at the TRB Innovations in Travel Demand Modeling Conference, Austin, Texas (2006). With Brenda (Bin) Zhou.  

 

• Microsimulation of Residential Land Development and Household Location Choices: Bidding for Land in Austin, Texas

  Proceedings the 87th Annual Meeting of the Transportation Research Board, in Washington D.C. (2008) and forthcoming in Transportation Research Record. With Bin (Brenda) Zhou.  

   

• Spatial Econometric Models for Panel Data: Incorporating Spatial and Temporal Data

Transportation Research Record No. 1902: 80-90 (2005). With Chris Frazier. 

 

• Location Choice vis-a-vis Transportation: The Case of Recent Home Buyers

Presented at the 11th International Conference of Travel Behavior Research, hosted by the International Association of Travel Behavior Research (IATBR) (Japan 2006) and forthcoming in the conference compendium, The Expanding Sphere of Travel Behaviour Research, Kitamura, R. and T. Yoshii (Eds.) (2008). With Michelle Bina & David Suescun.  

 

• Location Choice vis-à-vis Transportation: The Case of Apartment Dwellers

  Transportation Research Record No. 1977: 93-102 (2006) With Michelle Bina & Valdemar Warburg.  

   

• Modeling the Choice of Residential Location and Home Type: Recent Movers in Austin, Texas

  Proceedings the 87th Annual Meeting of the Transportation Research Board, in Washington D.C. (2008) and under review for publication in Transportation Research Record. With Khandker Nurul Habib. 

   

• Self-Selection in Home Choice: Use of Treatment Effects in Evaluating the Relationship between the Built Environment and Travel Behavior

  Proceedings of the 87th Annual Meeting of the Transportation Research Board, in Washington D.C. (2007), and accepted for publication in Transportation Research Record. With Brenda (Bin) Zhou. 

   

• The Introduction of Dynamic Features in a Random-Utility-Based Multiregional Input-Output Model of Trade, Production, and Location Choice  

  Proceedings of the 86th Annual Meeting of the Transportation Research Board (2007), and forthcoming in Journal of the Transportation Research Forum. With Tian Huang.  

  ** REFER TO RUBMRIO WEBSITE FOR FREE DOWNLOADS OF ALL CODE (UNCOMPILED) & DATA INPUTS (FOR TEXAS TRADE) **

   

• Evaluation of the Trans-Texas Corridor Proposal: Application and Enhancements of the Random-Utility-Based Multiregional Input-Output Model

Journal of Transportation Engineering 132 (7): 531-539 (2006). With Natalia Ruiz-Juri. 

 

• Extending the Random-Utility-Based Multiregional Input-Output Model: Incorporating Land Use Constraints, Domestic Demand & Network Congestion in a Model of Texas Trade

Proceedings of the 83rd Annual Meeting of the Transportation Research Board (2004). With Natalia Ruiz-Juri. 

 

• Tracking Land Use, Transport, and Industrial Production using Random-Utility Based Multiregional Input-Output Models: Applications for Texas Trade

Journal of Transport Geography 13: 275-286 (2005). With Ling Jin, Yong Zhao, and Natalia Ruiz-Juri.

 

• The Random-Utility-Based Multiregional Input-Output Model: Solution Existence and Uniqueness

Transportation Research 38B (9): 789-807 (2004). With Yong Zhao.

 

• Uncertainty Analysis and its Impacts on Decision-Making in an Integrated Transportation and Gravity-based Land Use Model

Under review for presentation at the 88th Annual Meeting of the Transportation Research Board and for publication in Transportation Research Record. (2008) With Jennifer Duthie, Avinash Voruganti and Travis Waller.

 

• Propagation of Uncertainty in Transportation-Land Use Models: An Investigation of DRAM-EMPAL and UTPP Predictions in Austin, Texas

Transportation Research Record No. 1831: 219-229 (2003). With Sriram Krishnamurthy.

 

• Uncertainty Propagation in an Integrated Land Use-Transport Modeling Framework: Output Variation via UrbanSim

Transportation Research Record No. 1805: 128-135 (2002). With Anant Pradhan.

• Visioning vs. Modeling: Analyzing the Land Use-Transportation Futures of Urban Regions 

  Journal of Urban Planning and Development 134 (3) (2008). With Jason Lemp, Brenda (Bin) Zhou, and Barbara Parmenter.

   

• Applications of Integrated Models of Land Use & Transport: A Comparison of ITLUP & UrbanSim

  Presented at the 54th Annual North American Meetings of the Regional Science Association International, Savannah, Georgia, November 2007. And under review for publication in International Regional Science Review. With Jen Duthie, Brenda (Bin) Zhou, and Varun Valsaraj.

Go Top

RESEARCH: Travel Demand

• From Aggregate Methods to Microsimulation: Assessing the Benefits of Microscopic Activity-Based Models of Travel Demand 

  Transportation Research Record 1994: 80-88. With Laura McWethy and Jason Lemp.  

   

• Continuous Departure Time Models: A Bayesian Approach  

  Presented at the 11th World Conference on Transport Research, Berkeley, California (2007), and under consideration for publication in Transportation. With Shashank Gadda and Paul Damien.  

   

• The Propagation of Uncertainty through Travel Demand Models

Annals of Regional Science 36 (1): 145-163 (2002).  With Yong Zhao.

 

• Travel Behavior as a Function of Accessibility, Land Use Mixing, and Land Use Balance: Evidence from the San Francisco Bay Area

Transportation Research Record No. 1607: 117-125 (1997)

 

• A New Approach for Travel Demand Modeling: Linking Roy's Identity to Discrete Choice

Transportation Research 38B (5): 459-475 (2004). With Sriram Krishnamurthy.

 

• A Utility-Theory-Consistent System-of-Demand-Equations Approach to Household Travel Choice

PhD Dissertation, University of California at Berkeley, Department of Civil and Environmental Engineering (1998).  Also: “Application of a Utility-Theory-Consistent System-of-Demand-Equations Approach to Household Travel Choice” in Transportation Research Record No. 1676 (1999) & “ A Model for Time- and Budget-Constrained Activity Demand Analysis ” Transportation Research 35B (3): 255-269 (2001)

 

• Welfare Calculations in Discrete-Choice Settings: The Role of Error Term Correlation

  Proceedings of the 87th Annual Meeting of the Transportation Research Board, in Washington D.C. (2008). With Yong Zhao and Anders Karlstrom. 

   

• Travel Demand and the Three Ds: Density, Diversity, and Design.
Transportation Research D, 2 (3): 199-219 (1997).  With Robert Cervero.

 

• Which Matters More in Mode Choice: Income or Density?
Compendium of Technical Papers. Institute of Transportation Engineers 65th Annual Meeting. (1995)

• Traveler Response to the 2005 Gas Price Spike  

  Proceedings of the 86th Annual Meeting of the Transportation Research Board (2007). With Matthew Bomberg.

Go Top

RESEARCH: Property Valuation

• The Effects of Location Elements on Home Purchase Prices and Rents:

Evidence from the San Francisco Bay Area, Transportation Research Record No. 1606: 40-50 (1997)

 

• The Costs of Right of Way Acquisition: Methods and Models for Estimation

Journal of Transportation Engineering 131 (3): 193-204 (2005). With Jared Heiner. 

 

• Right-of-Way Acquisition and Property Condemnation: A Comparison of U.S. State Laws

Journal of the Transportation Research Forum 44 (3): 45-58 (2005). With Shadi Hakimi. 

 

• Accessibility Indices: A Connection to Residential Land Prices and Location Choice

Transportation Research Record No. 1805: 25-34 (2002). With Issar Srour & Travis Dunn.

 

• Property Values and Highway Expansions: An Investigation of Timing, Size, Location, and Use Effects

Transportation Research Record No. 1812: 191-200 (2002). With Brian tenSiethoff.

 

• The Value of Travel Savings, as Reflected in Housing Prices:
A Study of Alameda County Homes (1997)

Go Top

RESEARCH: Vehicle Distinctions

• Quantifying the External Costs of Vehicle Use: Evidence from America's Top-Selling Light-Duty Models

Proceedings the 87th Annual Meeting of the Transportation Research Board, in Washington D.C. (2008) and under review for publication in Transportation Research Part D. With Jason Lemp.

 

• Effects of Light-Duty Trucks on the Capacity of Signalized Intersections

Journal of Transportation Engineering 126 (6): 506-512 (2000). Also, described in Jan. 16, 2000, New York Times article. With Raheel Shabih.

 

• To LDT or Not to LDT: An Assessment of the Principal Impacts of Light-Duty Trucks

Transportation Research Record No. 1738: 3-10 (2000).

• Behavioral Distinctions: The Use of Light-Duty Trucks and Passenger Cars

Journal of Transportation and Statistics 3 (3): 47-60 (2000). With Yong Zhao.

 

• Opportunities for and Impacts of Carsharing: A Survey of the Austin, Texas Market

  Proceedings the 87th Annual Meeting of the Transportation Research Board, in Washington D.C. (2008) and under review for publication in Transportation Research Record. With Brenda Zhou and Rui Gao.

   

• Household Vehicle Ownership by Vehicle Type: Application of a Multivariate Negative Binomial Model

Presented at the Transportation Research Board's 81st Annual Meeting, Washington D.C. (2001). With Yong Zhao.

Go Top

RESEARCH: Traffic Safety

• A Multivariate Poisson-Lognormal Regression Model for Prediction of Crash Counts by Severity, using Bayesian Methods 

  Accident Analysis and Prevention 40: 964-975 (2008). With Jianming Ma and Paul Damien.

   

• Safety Impacts and Other Implications of Raised Speed Limits on High-Speed Roads

National Cooperative Highway Research Program (NCHRP) Report 17-23 (2006). With Jon Bottom, Young-Jun Kweon, Jianming Ma, and Xiaokun (Cara) Wang. 

 

• Bayesian Multivariate Poisson Regression for Models of Injury Count, by Severity

Transportation Research Record No. 1950: 24-34. (2006) With Jianming Ma.

 

• Crash Modeling Using Clustered Data from Washington State: Prediction of Optimal Speed Limits

Proceedings of the IEEE Intelligent Transportation Systems Conference, Toronto (2006) With Jianming Ma.

 

• Occupant Injury Severity using a Heteroscedastic Ordered Logit Model: Distinguishing the Effects of Vehicle Weight and Type

Transportation Research Record No. 1908: 195-204 (2005). With Xiaokun (Cara) Wang.

 

• The Safety Effects of Speed Limit Changes: Use of Panel Models, Including Speed, Use and Design Variables

Transportation Research Record No. 1908: 148-158 (2005). With Young-Jun Kweon.

 

• Spatially Diaggregate Panel Models of Crash and Injury Count: The Effects of Speed Limits & Design

Proceedings of the 83rd Annual Meeting of the Transportation Research Board (2004). With Young-Jun Kweon.

 

• Freeway Speeds and Speed Variations Preceding Crashes, Within and Across Lanes

Journal of the Transportation Research Forum 46 (1): 43-62 (2007), and Proceedings of the 83rd Annual Meeting of the Transportation Research Board (2004). With Jianming Ma.

 

• Anticipating Injury and Death: Controlling for New Variables on Southern California Highways

Proceedings of the 83rd Annual Meeting of the Transportation Research Board. (2004) With Jianming Ma.

 

• Driver Attitudes and Choices: Speed Limits, Seatbelt Use, and Drinking-and-Driving

Journal of the Transportation Research Forum 45 (3):39-56 (2006), and Proceedings of the Transportation Research Board's 82nd Annual Meeting (2003). With Young-Jun Kweon.

 

• Overall Injury Risk to Different Drivers: Combining Exposure, Frequency, and Severity Models

Accident Analysis and Prevention 35 (4): 313-321 (2003). With Young-Jun Kweon. 

 

• Driver Injury Severity: An Application of Ordered Probit Model

Accident Analysis and Prevention 34 (3): 313-321 (2002). With Young-Jun Kweon. 

Go Top

RESEARCH: Traffic Flow

• Estimates of AADT: Quantifying the Uncertainty  

  Presented at the World Conference on Transportation Research, Berkeley, California (2007). And under consideration for publication in Journal of Transportation Engineering. With Shashank Gadda and Atul Magoon.  

• Modeling Traffic’s Flow-Density Relation: Accommodation of Multiple Flow Regimes and Traveler Types

Transportation 24 (4): 363-374 (2001)

 

• Changes in the Flow-Density Relation due to Environmental, Vehicle, and Driver Characteristics,

  Transportation Research Record No. 1644: 47-56 (1998)

   

• Chaos Theory & Transportation Systems: An Instructional Example

Transportation Research Record No. 1897: 9-17 (2004). With Chris Frazier. 

 

• A Comparison of Static and Dynamic Traffic Assignment Under Tolls: A Study of the Dallas-Fort Worth Network

  Proceedings of the 85th Annual Meeting of the Transportation Research Board (2006). With Steven Boyles, Satish Ukkusuri, and S. Travis Waller.

RESEARCH & REPORTS: Other

• GHG Emissions Control Options: Opportunities for Conservation 

  Report Commissioned by the National Academy of Sciences for the Committee for the Study on the Relationships Among Development Patterns, VMT, and Energy Conservation. (2008) With Matt Bomberg, Melissa Thompson, and Charlotte Whitehead.

   

• Travel Choices and their Relative Contributions to Climate Change: What Behavioral Shifts Will Buy Us, and Opportunities for Household Capping  

  Working Paper, to be submitted for Presentation at the 88th Annual Meeting of the Transportation Research Board, Washington, D.C. (2009). With Melissa Thompson & Charlotte Whitehead.  

   

• Maximum Simulated Likelihood Estimation with Correlated Observations: A Comparison of Simulation Techniques 

  Presented at the 53rd North American Regional Science Association International (RSAI) Conference, Toronto, Canada (2005), and forthcoming in Monograph on Transportation Statistics (J.D. Ross Publishing, 2008). With Xiaokun (Cara) Wang.  

   

• The Impacts of Bypasses on Small- and Medium-Sized Communities: An Econometric Analysis

Journal of Transportation and Statistics 5 (2): 57-69 (2002).  With Siva Srinivasan. (Also, The Impacts of Highway Relief Routes on Small Towns in Texas, TxDOT Final Report Project 1843, with Susan Handy, Scott Kubly, Siva Srinivasan, James Jarrett, Michael Oden & Hani Mahmassani.)

 

• Reducing Burden and Sample Sizes in Multi-day Household Travel Surveys

  Proceedings the 87th Annual Meeting of the Transportation Research Board, in Washington D.C. (2008) and forthcoming in Transportation Research Record. With Peter Stopher, Stephen Greaves, and Eoin Clifford. 

   

• State-Local Coordination in Managing Land Use and Transportation Along State Highways

  Journal of Urban Planning and Development 131 (1): 10-18 (2005). With Salila Vanka and Susan Handy.

   

• Frontage Roads: An Assessment of Legal Issues, Design Decisions, Costs, Operations, and Land-Development Differences Journal of Transportation Engineering 129 (3) (2003). With Randy Machemehl, Aaron Overman, Jacob Sesker, Marwan Madi, Jean (Jenny) Peterman, and Susan Handy. Based on Texas DOT Final Report, Project 1843.

 

• Research on Relationships Between Transportation Infrastructure & Increases in Vehicle Miles Traveled: The Effects of Highway Capacity Expansion on Land Development
Final EPA Report.  With Brian tenSiethoff, C. Michael Walton, and Hani Mahmassani. (Also, published as Transportation Research Record No. 1812 (2002).

 

• Sidewalk Cross-Slope Design: Analysis of Accessibility for Persons with Disabilities

Winner of the TRB 2002 Pedestrian Committee's Best Paper Award.  Published in Transportation Research Record No. 1818: 108-118 (2002).  With Lydia Heard, Young-Jun Kweon, and Tom Rioux.  Based on Final Research Report for TxDOT Project 0-4171 (2002).

 

• Meeting the Intent of ADA in Sidewalk Cross-Slope Design 

  Journal of Rehabilitation Research and Development 38 (1). With Yong Zhao & Chessalay Blanchard-Zimmerman. (2001)

   

• Sidewalk Cross-Slope Requirements of the American with Disabilities Act

  Transportation Research Record No. 1705 (2000). With Yong Zhao, Lydia Heard, Dean Taylor, and Beth Taylor. And based on Methods for Meeting the ADA in Sidewalk Cross-Slope Design Summary Report 4933-S, Center for Transportation Research, Prepared for the Texas Department of Transportation. With Yong Zhao & Chessalay Blanchard-Zimmerman. (2000)

   

• Urban Accessibility Indices: A Literature Review, Accessibility Measures: Formulation Considerations and Current Applications, Assessment of Accessibility Measures, & Development of an Urban Accessibility Index: Formulations, Aggregation, and Application. TxDOT Research Reports No. 4938-1 through -4. With Chandra Bhat, Susan Handy, Hani Mahmassani, Qinglin Chen, Lisa Weston, Issam Srour, & Anand Gopal.

   

• Techniques for Mitigating Urban Sprawl: Report 1 & Techniques for Mitigating Urban Sprawl: Report 2. TxDOT Research Reports No. 4420-1 and -2. With Susan Handy, Robert Paterson, Chandra Bhat, Jumin Song, Jayanthi Rajamani, & Juchul Jung.

   

• Traffic Congestion, Chapter 22 in Transportation Engineer's Handbook

Published by McGraw-Hill (2004)

 

• High-Speed Rail for California: A Cost-Benefit Analysis.

Berkeley Planning Journal, Volume 9: 61-80 (1994)

 

• Nonparametric Estimation of Household VMT
(2004) With Young-Jun Kweon.

Berkeley Planning Journal, Volume 9: 61-80 (1994)

 

• Student Grades & Course Evaluations in Engineering: What Makes a Difference

Presented at the ASEE Annual Conference, Albuquerque, New Mexico, June 2001, and at the ASEE Gulf Section Annual Conference, College Station, Texas, March 2001

 

• Critical Elements of a High-Quality Research Paper

  Slides for Invited Presentation at the 87th Annual Meeting of the Transportation Research Board (2008).