Dr. Randy Machemehl, Ph.D., P.E.

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Randy B. Machemehl, Ph.D., P.E., is a Professor of Transportation Engineering at The University of Texas and former Director of the Center for Transportation Research. He was in private engineering practice as a staff member of Wilbur Smith and Associates before joining the faculty of The University of Texas at Austin in 1978. He is active in many professional organizations, having served in the American Society of Civil Engineers and The Institute of Transportation Engineers at both the state and national levels and as President of the Council of University Transportation Centers. His research activities are numerous, addressing a wide range of transportation topics and modes that are generally concentrated in transportation system operations. Dr. Machemehl has been a principal or co-principal investigator on more than 300 research studies for the U. S. Department of Transportation, Federal Highway Administration, Federal Transit Administration, The Texas Department of Transportation, and The Texas Governor's Office.  Results of his research have been published in over 300 technical reports and papers. Current research initiatives include:

  • Traffic Modeling Support for Pavement Design and Planning This initiative will further enhance a GIS-based tool that forecasts locations likely to experience unusual substantial loading.  Suburban and rural areas are generally served by thin pavement structures that could be easily damaged by heavy loading. High volume highways typically have strong pavements that are not as susceptible to damage. As land use changes, the likelihood that these thin pavements in booming suburban and rural areas are subject to unusually heavy loading increases.  In fact, these loadings can cause pavements to fail before the end of expected service lives. Many booming rural and suburban areas in Texas have been ranked as the fastest growing in the recent years. As a result of the rapid development, many trucks are expected to travel on pavements designed without this type of heavy truck traffic in mind. By forecasting future high damage locations, officials can take anticipatory action and use this GIS-based system to provide a remaining life analysis for pavement rehabilitation planning. 
  • Assessing Delay Costs Associated with the Temporary Use of Public Right of Way in Austin, TX Many times during large construction projects, property developers need to rent public space (i.e. street lanes and sidewalks) in order to complete a project.  This work effort will produce a rational basis for fees charged for use of public Right of Way by the City. This project will identify the delays and costs to the transportation network associated with the temporary removal of public right of way. Such analyses are easily done using micro-simulation techniques if the roadway section is isolated and the analysis uses counted current traffic volumes.  However, if the road is imbedded in a mature network, travelers avoiding the construction zone may significantly affect the resulting alternative paths.  Such network impacts can be predicted using Dynamic Traffic Assignment (DTA) techniques, but are likely to be significant only for certain routes and only for certain demand conditions.  Data will be evaluated for AM, Midday, PM, and Weekend time periods to account for variable costs based on variable roadway conditions. Measures of loss of service such as volumes, stops, travel times, delay, and speeds will provide a basis for determining costs. 
  • The True Cost of Commute This project has prepared a system that will enable the estimation of total travel costs for selected trips by bus, auto, bicycle, and walk modes. Examples of costs include: 1) for driving – travel time, taxes, operating costs, tires, noise pollution, accident risks; 2) for bus – fares, wait time, travel time, emissions, infrastructure, operating costs, noise pollution; 3) for walking – travel time, risk of pedestrian accidents, health care savings (due to improved health); 4) for bicycle – travel time, operating cost, bike gear, maintenance, taxes, and risk of accidents.
  • Quantifying the Effect of Installing Bicycle Signals in Austin, TX The use of optional bicycle signal faces has been approved through a MUTCD Interim Approval. This project will conduct a before and after study for bicycle signals installed in the City of Austin. Signals will be installed in Fall 2016 throughout downtown Austin. We will evaluate the effect of installing bicycle signals on compliance, delay, accidents, and rate of bicycle facility usage.
  • IH 35 Operational Study for Williamson County This project consists of operational studies as directed by Williamson County and the City of Round Rock. The studies will focus on vehicular and freight traffic to enhance connectivity to IH 35, identify congestion mitigation recommendations, and prepare preliminary exhibits and cost estimates. The general study area will consist of the IH 35 corridor between RM 1431 and SH 45. 
  • Development of an Interactive GIS Based Work Zone Traffic Control Design Tool This study will develop a methodology for enabling sub-network analyses in the context of a large network Dynamic Traffic Assignment (DTA) model. DTA tools are currently being applied to large urban networks and they provide the best available methodology for identifying network implications of temporary capacity changes, such as work zones, to selected links. However, the computational burden of DTA application for a large network is extreme requiring days for completion and the typical work zone analysis gains very little from a complete network analysis. A sub-network analysis tool would enable DTA application for work zone capacity disruptions but would perform the traffic assignment only for the partial network that is likely affected with much less computational burden and vastly improved response times. This effort will include developing a methodology on a prototype network, testing that methodology, and creating an algorithm for implementation. For full-scale implementation, an existing DTA network model, probably the Dallas, Texas network will be used to provide consistency with the Dallas District Traffic Control Planning (TCP) GIS tool. Ultimately, it is intended that the GIS tool and the DTA model be linked to establish a seamless process of importing and exporting information between the two software programs, as required to complete a TCP evaluation. It is intended that roadway capacity changes be input into the GIS tool by the user and this information be exported to the DTA model. The sub-network tool will feed the DTA model that will be run to provide analysis outputs, including link volumes and speeds for the affected area. This information will be converted into travel times, delay, and level of service information within the GIS tool to provide user-friendly feedback for completing the TCP assessment.