Heavy Vehicle Performance during Recovery from Forced-flow Urban Freeway Conditions due to Incidents, Work Zones and Recurring Congestion

Quarterly Reports Other Documents Final Report
December 2010
March 2011
June 2011
September 2011
December 2011
June 2012
September 2012
December 2012
March 2013
March 2014
Final Report

Primary Investigator

Yue Liu
University of Wisconsin–Milwaukee
PO Box 784
Milwaukee, WI 53201


There is strong empirical and theoretical evidence that heavy trucks’ influence on urban freeway congestion increases dramatically under forced-flow conditions that are becoming more prevalent in the urban environment due to overall increases in traffic and the deployment of work zones. Preliminary research suggests that with just a 16% truck presence, capacity may drop nearly 50% under stop-and-go traffic. However, the Highway Capacity Manual and other design guidelines pay little attention to forced flow conditions. A large vehicle classification dataset will be collected and calibrated simulation models will be used to establish truck influence under forced-flow traffic conditions.


To fill a significant gap in knowledge about truck performance under forced flow conditions.


  1. Literature review
  2. Field data collection and analysis
  3. Simulation input preparation
  4. Examine simulation package suitability
  5. Simulation calibration existing location
  6. Simulation calibration new locations
  7. Scenario testing
  8. Document field data analysis
  9. Document simulation
  10. Draft report/Final report

Project Information

  • Duration: 24 months
  • Dates: September 1, 2010 – August 31, 2012
  • Budget: CFIRE: $149,993; Total: $224,257
  • Student Involvement: Two graduate students and two undergraduates
  • Modal Orientation: Highway
  • Project ID: CFIRE 04-17
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