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• 1. [Article] Forecasting for local water management

  Forecast models are investigated and developed for use in local water management to aid in determining short term water requirements and availability. The forecast models include precipitation occurrence ...

  Citation × Citation Citation Abstract Copy Title: Forecasting for local water management Author: Putnam, Douglas Alan Year: 1985 Forecast models are investigated and developed for use in local water management to aid in determining short term water requirements and availability. The forecast models include precipitation occurrence and depth using a Markov chain model, temperature and solar radiation with a multivariate autoregressive model, and streamflow with autoregressive-moving average models. The precipitation, temperature, and solar radiation forecasts are used with a soil moisture model to determine water demands. A state space approach to the Muskingum-Cunge streamflow routing technique is developed. The forecast water demands and streamflow forecasts are used as inputs to this routing model. Forecast model errors and propagation of these errors from one model into the next are investigated. Title: Forecasting for local water management Author: Putnam, Douglas Alan Year: 1985 Forecast models are investigated and developed for use in local water management to aid in determining short term water requirements and availability. The forecast models include precipitation occurrence and depth using a Markov chain model, temperature and solar radiation with a multivariate autoregressive model, and streamflow with autoregressive-moving average models. The precipitation, temperature, and solar radiation forecasts are used with a soil moisture model to determine water demands. A state space approach to the Muskingum-Cunge streamflow routing technique is developed. The forecast water demands and streamflow forecasts are used as inputs to this routing model. Forecast model errors and propagation of these errors from one model into the next are investigated. Close

• 2. [Article] Development of a Pedestrian Demand Estimation Tool: a Destination Choice Model

  There is growing support for improvements to the quality of the walking environment, including more investments to promote pedestrian travel. Planners, engineers, and others seek improved tools to estimate ...

  Citation × Citation Citation Abstract Copy Title: Development of a Pedestrian Demand Estimation Tool: a Destination Choice Model Author: Muhs, Christopher D., Clifton, Kelly, Singleton, Patrick Allen, Schneider, Robert J. Year: 2015 There is growing support for improvements to the quality of the walking environment, including more investments to promote pedestrian travel. Planners, engineers, and others seek improved tools to estimate pedestrian demand that are sensitive to environmental and demographic factors at the appropriate scale in order to aid policy-relevant issues like air quality, public health, and smart allocation of infrastructure and other resources. Further, in the travel demand forecasting realm, tools of this kind are difficult to implement due to the use of spatial scales of analysis that are oriented towards motorized modes, vast data requirements, and computer processing limitations. To address these issues, a two-phase project between Portland State University and Oregon Metro is underway to develop a robust pedestrian planning method for use in regional travel demand models. The first phase, completed in 2013, utilizes a tool that predicts the number of walking trips generated with spatial acuity, based on a new measure of the pedestrian environment and a micro-level unit of analysis. Currently, phase two is building upon this tool to predict the distribution of walking trips, connecting the origins predicted in phase one to destinations. This presentation will focus on phase two, which is one of the first studies to focus on destination choices among pedestrians separately from other modes. The approach can be extended to identify the spatial extent of potential pedestrian paths to these destinations. Ultimately, the products developed from the research can estimate various aspects of pedestrian demand – trip generation, trip distribution, and areas of potential pedestrian activity. These tools will add to the analytical methods available for transportation modeling, pedestrian and safety analysis, health assessments, and other pedestrian planning applications. Title: Development of a Pedestrian Demand Estimation Tool: a Destination Choice Model Author: Muhs, Christopher D., Clifton, Kelly, Singleton, Patrick Allen, Schneider, Robert J. Year: 2015 There is growing support for improvements to the quality of the walking environment, including more investments to promote pedestrian travel. Planners, engineers, and others seek improved tools to estimate pedestrian demand that are sensitive to environmental and demographic factors at the appropriate scale in order to aid policy-relevant issues like air quality, public health, and smart allocation of infrastructure and other resources. Further, in the travel demand forecasting realm, tools of this kind are difficult to implement due to the use of spatial scales of analysis that are oriented towards motorized modes, vast data requirements, and computer processing limitations. To address these issues, a two-phase project between Portland State University and Oregon Metro is underway to develop a robust pedestrian planning method for use in regional travel demand models. The first phase, completed in 2013, utilizes a tool that predicts the number of walking trips generated with spatial acuity, based on a new measure of the pedestrian environment and a micro-level unit of analysis. Currently, phase two is building upon this tool to predict the distribution of walking trips, connecting the origins predicted in phase one to destinations. This presentation will focus on phase two, which is one of the first studies to focus on destination choices among pedestrians separately from other modes. The approach can be extended to identify the spatial extent of potential pedestrian paths to these destinations. Ultimately, the products developed from the research can estimate various aspects of pedestrian demand – trip generation, trip distribution, and areas of potential pedestrian activity. These tools will add to the analytical methods available for transportation modeling, pedestrian and safety analysis, health assessments, and other pedestrian planning applications. Close

• 3. [Article] Multi-Criteria Trucking Freeway Performance Measures in Congested Corridors

  Research was undertaken to develop multicriteria tools for measuring and analyzing the impact of recurring and nonrecurring congestion on freight. Unlike previous studies, this work used several distinct ...

  Citation × Citation Citation Abstract Copy Title: Multi-Criteria Trucking Freeway Performance Measures in Congested Corridors Author: Figliozzi, Miguel, Wheeler, Nikki Year: 2011 Research was undertaken to develop multicriteria tools for measuring and analyzing the impact of recurring and nonrecurring congestion on freight. Unlike previous studies, this work used several distinct data sources to analyze the effects of congestion on I-5 in the Portland, Oregon, metropolitan area: Global Positioning System data from commercial trucks, Oregon Department of Transportation corridor travel time loop data, and incident data. A new methodology and algorithms combine these data sources and estimate the impact of recurrent and nonrecurrent congestion on reliability and delays, costs, and emissions of freight movements. The results suggest that traditional traffic sensor data tend to underestimate the impact of congestion on travel times and variability of commercial vehicles. Congestion is detrimental not only for carriers' and shippers' costs but also for the planet because of increases in greenhouse gas emissions and for the local community because of increases in oxides of nitrogen, particulate matter, and other harmful pollutants. The developed methodology can provide useful freight operation and performance data for the freight community, transportation decision makers, and other transportation stakeholders. For more information: http://archives.pdx.edu/ds/psu/11487 Title: Multi-Criteria Trucking Freeway Performance Measures in Congested Corridors Author: Figliozzi, Miguel, Wheeler, Nikki Year: 2011 Research was undertaken to develop multicriteria tools for measuring and analyzing the impact of recurring and nonrecurring congestion on freight. Unlike previous studies, this work used several distinct data sources to analyze the effects of congestion on I-5 in the Portland, Oregon, metropolitan area: Global Positioning System data from commercial trucks, Oregon Department of Transportation corridor travel time loop data, and incident data. A new methodology and algorithms combine these data sources and estimate the impact of recurrent and nonrecurrent congestion on reliability and delays, costs, and emissions of freight movements. The results suggest that traditional traffic sensor data tend to underestimate the impact of congestion on travel times and variability of commercial vehicles. Congestion is detrimental not only for carriers' and shippers' costs but also for the planet because of increases in greenhouse gas emissions and for the local community because of increases in oxides of nitrogen, particulate matter, and other harmful pollutants. The developed methodology can provide useful freight operation and performance data for the freight community, transportation decision makers, and other transportation stakeholders. For more information: http://archives.pdx.edu/ds/psu/11487 Close

• 4. [Article] Evaluating the Use of Crowdsourcing as a Data Collection Method for Bicycle Performance Measures and Identification of Facility Improvement Needs

  This research developed a smartphone application called ORcycle to collect cyclists’ routes, users, and comfort levels. ORcycle combines GPS revealed route data collection with new questionnaires that ...

  Citation × Citation Citation Abstract Copy Title: Evaluating the Use of Crowdsourcing as a Data Collection Method for Bicycle Performance Measures and Identification of Facility Improvement Needs Author: Figliozzi, Miguel A., Blanc, Bryan Philip Year: 2015 This research developed a smartphone application called ORcycle to collect cyclists’ routes, users, and comfort levels. ORcycle combines GPS revealed route data collection with new questionnaires that try to elicit cyclists’ attitudes as well as comfort levels and factors that influence their perceived comfort and route choice. The new questionnaires were developed to better understand how cyclists’ comfort levels are affected by route characteristics, route stressors, safety reports, cyclists’ demographics, and cyclists’ cycling attitude. Preliminary results show that many trip characteristics, route choice factors, route stressors and demographic variables are correlated with comfort levels. ORcycle is the first statewide deployment of a smartphone application to collect bicycle specific safety and crash data in addition to travel and comfort data. Potential applications that can take advantage of the ORcycle data include: comfort and route models, prioritization of network improvements, and crash and injury risk models. Title: Evaluating the Use of Crowdsourcing as a Data Collection Method for Bicycle Performance Measures and Identification of Facility Improvement Needs Author: Figliozzi, Miguel A., Blanc, Bryan Philip Year: 2015 This research developed a smartphone application called ORcycle to collect cyclists’ routes, users, and comfort levels. ORcycle combines GPS revealed route data collection with new questionnaires that try to elicit cyclists’ attitudes as well as comfort levels and factors that influence their perceived comfort and route choice. The new questionnaires were developed to better understand how cyclists’ comfort levels are affected by route characteristics, route stressors, safety reports, cyclists’ demographics, and cyclists’ cycling attitude. Preliminary results show that many trip characteristics, route choice factors, route stressors and demographic variables are correlated with comfort levels. ORcycle is the first statewide deployment of a smartphone application to collect bicycle specific safety and crash data in addition to travel and comfort data. Potential applications that can take advantage of the ORcycle data include: comfort and route models, prioritization of network improvements, and crash and injury risk models. Close

• 5. [Article] State space approach to flood stage estimation

  A flood routing and stage prediction model is developed using the techniques of State Space and Kalman filtering. The governing equation is the physically based hydrologic method of flood routing with ...

  Citation × Citation Citation Abstract Copy Title: State space approach to flood stage estimation Author: Jones, Gregory Allen Year: 1984 A flood routing and stage prediction model is developed using the techniques of State Space and Kalman filtering. The governing equation is the physically based hydrologic method of flood routing with the output being an optimal estimate of stage given known inputs of streamflow. These equations are developed in state space and the Kalman filter is employed to estimate the flow and river stage. The model is applied to the Toutle and Cowlitz Rivers in the State of Washington, where the stage is affected by a shifting bed elevation. With the deterministic inputs at Mayfield Dam on the Cowlitz and Tower Road on the Toutle, the optimal output of stage is predicted at Castle Rock on the Cowlitz River. Addition of the Kalman Filter improves stage prediction based on an application to an observed storm event. Title: State space approach to flood stage estimation Author: Jones, Gregory Allen Year: 1984 A flood routing and stage prediction model is developed using the techniques of State Space and Kalman filtering. The governing equation is the physically based hydrologic method of flood routing with the output being an optimal estimate of stage given known inputs of streamflow. These equations are developed in state space and the Kalman filter is employed to estimate the flow and river stage. The model is applied to the Toutle and Cowlitz Rivers in the State of Washington, where the stage is affected by a shifting bed elevation. With the deterministic inputs at Mayfield Dam on the Cowlitz and Tower Road on the Toutle, the optimal output of stage is predicted at Castle Rock on the Cowlitz River. Addition of the Kalman Filter improves stage prediction based on an application to an observed storm event. Close

• 6. [Article] Estimating River Discharge Using Multiple-Tide Gauges Distributed Along a Channel

  Reliable estimation of freshwater inflow to the ocean from large tidal rivers is vital for water resources management and climate analyses. Discharge gauging stations are typically located beyond the tidal ...

  Citation × Citation Citation Abstract Copy Title: Estimating River Discharge Using Multiple-Tide Gauges Distributed Along a Channel Author: Moftakhari, Hamed R., Jay, David A, Talke, Stefan Year: 2016 Reliable estimation of freshwater inflow to the ocean from large tidal rivers is vital for water resources management and climate analyses. Discharge gauging stations are typically located beyond the tidal intrusion reach, such that inputs and losses occurring closer to the ocean are not included. Here, we develop a method of estimating river discharge using multiple gauges and time-dependent tidal statistics determined via wavelet analysis. The Multiple-gauge Tidal Discharge Estimate (MTDE) method is developed using data from the Columbia River and Fraser River estuaries and calibrated against river discharge. Next, we evaluate the general applicability of MTDE by testing an idealized two-dimensional numerical model, with a convergent cross-sectional profile, for eighty-one cases in which nondimensional numbers for friction, river flow, and convergence length scale are varied. The simulations suggest that MTDE is applicable to a variety of tidal systems. Model results and data analyses together suggest that MTDE works best with at least three gauges: a reference station near the river mouth, and two upstream gauges that respond strongly to distinct portions of the observed range of flow. The balance between tidal damping and amplifying factors determines the favorable location of the gauges. Compared to previous studies, the MTDE method improves the time resolution of estimates (from 2.5 to < 1 week) and is applicable to systems with mixed diurnal/semidiurnal tides. However, model results suggest that tide-induced residual flows such as the Stokes drift may still affect the accuracy of MTDE at seaward locations during periods of low river discharge. Title: Estimating River Discharge Using Multiple-Tide Gauges Distributed Along a Channel Author: Moftakhari, Hamed R., Jay, David A, Talke, Stefan Year: 2016 Reliable estimation of freshwater inflow to the ocean from large tidal rivers is vital for water resources management and climate analyses. Discharge gauging stations are typically located beyond the tidal intrusion reach, such that inputs and losses occurring closer to the ocean are not included. Here, we develop a method of estimating river discharge using multiple gauges and time-dependent tidal statistics determined via wavelet analysis. The Multiple-gauge Tidal Discharge Estimate (MTDE) method is developed using data from the Columbia River and Fraser River estuaries and calibrated against river discharge. Next, we evaluate the general applicability of MTDE by testing an idealized two-dimensional numerical model, with a convergent cross-sectional profile, for eighty-one cases in which nondimensional numbers for friction, river flow, and convergence length scale are varied. The simulations suggest that MTDE is applicable to a variety of tidal systems. Model results and data analyses together suggest that MTDE works best with at least three gauges: a reference station near the river mouth, and two upstream gauges that respond strongly to distinct portions of the observed range of flow. The balance between tidal damping and amplifying factors determines the favorable location of the gauges. Compared to previous studies, the MTDE method improves the time resolution of estimates (from 2.5 to < 1 week) and is applicable to systems with mixed diurnal/semidiurnal tides. However, model results suggest that tide-induced residual flows such as the Stokes drift may still affect the accuracy of MTDE at seaward locations during periods of low river discharge. Close

• 7. [Article] Feedback Between Residual Circulations and Sediment Distribution in Highly Turbid Estuaries: An Analytical Model

  Motivated by field studies of the Ems estuary which show longitudinal gradients in bottom sediment concentration as high as O(0.01 kg/m4), we develop an analytical model for estuarine residual circulation ...

  Citation × Citation Citation Abstract Copy Title: Feedback Between Residual Circulations and Sediment Distribution in Highly Turbid Estuaries: An Analytical Model Author: Talke, Stefan A., de Swart, Huib E., Schuttelaars, H. M. Year: 2009 Motivated by field studies of the Ems estuary which show longitudinal gradients in bottom sediment concentration as high as O(0.01 kg/m4), we develop an analytical model for estuarine residual circulation based on currents from salinity gradients, turbidity gradients, and freshwater discharge. Salinity is assumed to be vertically well mixed, while the vertical concentration profile is assumed to result from a balance between a constant settling velocity and turbulent diffusive flux. Width and depth of the model estuary are held constant. Model results show that turbidity gradients enhance tidally averaged circulation upstream of the estuarine turbidity maximum (ETM), but significantly reduce residual circulation downstream, where salinity and turbidity gradients oppose each other. We apply the condition of morphodynamic equilibrium (vanishing sediment transport) and develop an analytical solution for the position of the turbidity maximum and the distribution of suspended sediment concentration (SSC) along a longitudinal axis. A sensitivity study shows great variability in the longitudinal distribution of suspended sediment with the applied salinity gradient and six model parameters: settling velocity, vertical mixing, horizontal dispersion, total sediment supply, fresh water flow, and water depth. Increasing depth and settling velocity move the ETM upstream, while increasing freshwater discharge and vertical mixing move the ETM downstream. Moreover, the longitudinal distribution of SSC is inherently asymmetric around the ETM, and depends on spatial variations in the residual current structure and the vertical profile of SSC. Title: Feedback Between Residual Circulations and Sediment Distribution in Highly Turbid Estuaries: An Analytical Model Author: Talke, Stefan A., de Swart, Huib E., Schuttelaars, H. M. Year: 2009 Motivated by field studies of the Ems estuary which show longitudinal gradients in bottom sediment concentration as high as O(0.01 kg/m4), we develop an analytical model for estuarine residual circulation based on currents from salinity gradients, turbidity gradients, and freshwater discharge. Salinity is assumed to be vertically well mixed, while the vertical concentration profile is assumed to result from a balance between a constant settling velocity and turbulent diffusive flux. Width and depth of the model estuary are held constant. Model results show that turbidity gradients enhance tidally averaged circulation upstream of the estuarine turbidity maximum (ETM), but significantly reduce residual circulation downstream, where salinity and turbidity gradients oppose each other. We apply the condition of morphodynamic equilibrium (vanishing sediment transport) and develop an analytical solution for the position of the turbidity maximum and the distribution of suspended sediment concentration (SSC) along a longitudinal axis. A sensitivity study shows great variability in the longitudinal distribution of suspended sediment with the applied salinity gradient and six model parameters: settling velocity, vertical mixing, horizontal dispersion, total sediment supply, fresh water flow, and water depth. Increasing depth and settling velocity move the ETM upstream, while increasing freshwater discharge and vertical mixing move the ETM downstream. Moreover, the longitudinal distribution of SSC is inherently asymmetric around the ETM, and depends on spatial variations in the residual current structure and the vertical profile of SSC. Close

• 8. [Article] Recent Progress in Performance Evaluations and Near Real-Time Assessment of Operational Ocean Products

  Operational ocean forecast systems provide routine marine products to an ever-widening community of users and stakeholders. The majority of users need information about the quality and reliability of the ...

  Citation × Citation Citation Abstract Copy Title: Recent Progress in Performance Evaluations and Near Real-Time Assessment of Operational Ocean Products Author: Hernandez, Fabrice, Blockley, Edward, Brassington, Gary B., Davidson, Fraser, Divakaran, Prasanth, Drévillon, Marie, Ishizaki, Shiro, Garcia-Sotillo, Marcos, Hogan, Patrick J., Lagemaa, Priidik, Levier, Bruno, Martin, Matthew, Mehra, Avichal, Mooers, Christopher, Ferry, Nicolas, Ryan, Andrew, Regnier, Charly, Sellar, Alistair, Smith, Gregory C., Sofianos, Sarantis, Spindler, Todd, Volpe, Gianluca, Wilkin, John, Zaron, Edward, Zhang, Aijun Year: 2015 Operational ocean forecast systems provide routine marine products to an ever-widening community of users and stakeholders. The majority of users need information about the quality and reliability of the products to exploit them fully. Hence, forecast centres have been developing improved methods for evaluating and communicating the quality of their products. Global Ocean Data Assimilation Experiment (GODAE) OceanView, along with the Copernicus European Marine Core Service and other national and international programmes, has facilitated the development of coordinated validation activities among these centres. New metrics, assessing a wider range of ocean parameters, have been defined and implemented in real-time. An overview of recent progress and emerging international standards is presented here. Title: Recent Progress in Performance Evaluations and Near Real-Time Assessment of Operational Ocean Products Author: Hernandez, Fabrice, Blockley, Edward, Brassington, Gary B., Davidson, Fraser, Divakaran, Prasanth, Drévillon, Marie, Ishizaki, Shiro, Garcia-Sotillo, Marcos, Hogan, Patrick J., Lagemaa, Priidik, Levier, Bruno, Martin, Matthew, Mehra, Avichal, Mooers, Christopher, Ferry, Nicolas, Ryan, Andrew, Regnier, Charly, Sellar, Alistair, Smith, Gregory C., Sofianos, Sarantis, Spindler, Todd, Volpe, Gianluca, Wilkin, John, Zaron, Edward, Zhang, Aijun Year: 2015 Operational ocean forecast systems provide routine marine products to an ever-widening community of users and stakeholders. The majority of users need information about the quality and reliability of the products to exploit them fully. Hence, forecast centres have been developing improved methods for evaluating and communicating the quality of their products. Global Ocean Data Assimilation Experiment (GODAE) OceanView, along with the Copernicus European Marine Core Service and other national and international programmes, has facilitated the development of coordinated validation activities among these centres. New metrics, assessing a wider range of ocean parameters, have been defined and implemented in real-time. An overview of recent progress and emerging international standards is presented here. Close

• 9. [Article] Leveraging Signal Infrastructure for Nonmotorized Counts in a Statewide Program: Pilot Study

  Transportation agencies are beginning to explore and develop nonmotorized counting programs. This paper presents the results of a pilot study that tested the use of existing signal infrastructure—Model ...

  Citation × Citation Citation Abstract Copy Title: Leveraging Signal Infrastructure for Nonmotorized Counts in a Statewide Program: Pilot Study Author: Blanc, Bryan Philip, Johnson, Pamela, Figliozzi, Miguel A., Monsere, Christopher M., Nordback, Krista Year: 2015 Transportation agencies are beginning to explore and develop nonmotorized counting programs. This paper presents the results of a pilot study that tested the use of existing signal infrastructure—Model 2070 signal controllers with advanced software to log pedestrian phase actuations and detections from bicycle lane inductive loops—to count pedestrians and bicycles. The pilot study was conducted at a typical suburban signalized intersection with heavy motorized traffic that was instrumented on all four approaches with pedestrian push buttons and advance inductive loops in the bicycle lane for signal operation. One day (24 h) of video data was collected as ground truth. The data were reduced and compared with the controller logs. Results indicated that using pedestrian phases as a proxy for estimating pedestrian activity was a promising avenue for counting programs. During the pilot study day, 596 pedestrians crossed the intersection, and 482 pedestrian phases were logged (i.e., 1.24 pedestrian crossings per phase logged). However, bicycle counts were not as accurate because of a number of site-specific factors: (a) inductive loop location, (b) loop sensitivity settings, (c) loop shape, and (d) nearly half of the cyclists passing through the intersection were riding on the sidewalk. The pilot study was part of a research project to develop guidelines for a statewide bicycle and pedestrian counting program for the Oregon Department of Transportation. Title: Leveraging Signal Infrastructure for Nonmotorized Counts in a Statewide Program: Pilot Study Author: Blanc, Bryan Philip, Johnson, Pamela, Figliozzi, Miguel A., Monsere, Christopher M., Nordback, Krista Year: 2015 Transportation agencies are beginning to explore and develop nonmotorized counting programs. This paper presents the results of a pilot study that tested the use of existing signal infrastructure—Model 2070 signal controllers with advanced software to log pedestrian phase actuations and detections from bicycle lane inductive loops—to count pedestrians and bicycles. The pilot study was conducted at a typical suburban signalized intersection with heavy motorized traffic that was instrumented on all four approaches with pedestrian push buttons and advance inductive loops in the bicycle lane for signal operation. One day (24 h) of video data was collected as ground truth. The data were reduced and compared with the controller logs. Results indicated that using pedestrian phases as a proxy for estimating pedestrian activity was a promising avenue for counting programs. During the pilot study day, 596 pedestrians crossed the intersection, and 482 pedestrian phases were logged (i.e., 1.24 pedestrian crossings per phase logged). However, bicycle counts were not as accurate because of a number of site-specific factors: (a) inductive loop location, (b) loop sensitivity settings, (c) loop shape, and (d) nearly half of the cyclists passing through the intersection were riding on the sidewalk. The pilot study was part of a research project to develop guidelines for a statewide bicycle and pedestrian counting program for the Oregon Department of Transportation. Close

• 10. [Article] Algorithms for Studying the Impact of Travel Time Reliability Along Multisegment Trucking Freight Corridors

  Performance measures allow planners and engineers to monitor and evaluate transportation facilities or projects and to justify the allocation of funds among alternative transportation improvement options. ...

  Citation × Citation Citation Abstract Copy Title: Algorithms for Studying the Impact of Travel Time Reliability Along Multisegment Trucking Freight Corridors Author: Figliozzi, Miguel, Wheeler, Nikki, Albright, Eric, Walker, Lindsay, Sarkar, Shreemoyee, Rice, Danielle Year: 2011 Performance measures allow planners and engineers to monitor and evaluate transportation facilities or projects and to justify the allocation of funds among alternative transportation improvement options. To capture the impact of corridor congestion on freight vehicles, new tools and methodologies are developed to analyze data from commercial vehicles and produce performance measures such as travel time, speed, and travel time reliability. Because long freight corridors comprise segments with varying reliability characteristics, the objective was to develop a programming logic that would use available truck Global Positioning System data to (a) identify natural segments or regions in a corridor between urban centers, Interstate junctions, or rural areas and (b) estimate corridorwide impact of travel time unreliability. The case study presented investigates the I-5 corridor in Oregon. The research applies statistical techniques to compute vehicle travel time and reliability for freight movements within each segment. The proposed methodology has been used successfully to identify distinct segments and characteristics of travel time reliability in freight corridors. Travel time information was used to compute cost effects of delays within rural and urban areas along the I-5 corridor. The research presents an advance in the processing and aggregation of Global Positioning System truck data to produce succinct yet informative performance measures and segments. For more information: http://archives.pdx.edu/ds/psu/11487 Title: Algorithms for Studying the Impact of Travel Time Reliability Along Multisegment Trucking Freight Corridors Author: Figliozzi, Miguel, Wheeler, Nikki, Albright, Eric, Walker, Lindsay, Sarkar, Shreemoyee, Rice, Danielle Year: 2011 Performance measures allow planners and engineers to monitor and evaluate transportation facilities or projects and to justify the allocation of funds among alternative transportation improvement options. To capture the impact of corridor congestion on freight vehicles, new tools and methodologies are developed to analyze data from commercial vehicles and produce performance measures such as travel time, speed, and travel time reliability. Because long freight corridors comprise segments with varying reliability characteristics, the objective was to develop a programming logic that would use available truck Global Positioning System data to (a) identify natural segments or regions in a corridor between urban centers, Interstate junctions, or rural areas and (b) estimate corridorwide impact of travel time unreliability. The case study presented investigates the I-5 corridor in Oregon. The research applies statistical techniques to compute vehicle travel time and reliability for freight movements within each segment. The proposed methodology has been used successfully to identify distinct segments and characteristics of travel time reliability in freight corridors. Travel time information was used to compute cost effects of delays within rural and urban areas along the I-5 corridor. The research presents an advance in the processing and aggregation of Global Positioning System truck data to produce succinct yet informative performance measures and segments. For more information: http://archives.pdx.edu/ds/psu/11487 Close