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Joseph E Hummer - One of the best experts on this subject based on the ideXlab platform.
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safety analysis of the new synchronized and milwaukee b Interchanges in comparison to existing designs
Accident Analysis & Prevention, 2017Co-Authors: Amirarsalan Mehrara Molan, Joseph E HummerAbstract:Interchanges have high crash rates and large impacts on traffic operations. The main objective of this research is to analyze the safety performance of two new Interchanges, the synchronized interchange and the Milwaukee B interchange. The primary method of study was microscopic simulation modeling using the Surrogate Safety Assessment Model (SSAM) program to estimate the quantity and type of conflicting interactions in each interchange. A comprehensive series of simulation scenarios were considered to include different conditions of traffic volumes, traffic turning ratios, traffic distribution, and heavy vehicles percentages. Afterward, outcomes were analyzed with two-way Analyses of Variance (ANOVAs) to compare the mean values of conflicts. Based on the results, the diverging diamond interchange (DDI) and Milwaukee B were the safest designs regarding observed conflicting interactions in the simulation models; however, the DDI did not seem as reliable from the viewpoint of wrong way movements. The new synchronized interchange, the parclo B, and the Milwaukee A (an existing interchange in Milwaukee, WI) showed the same rate of conflicts. The synchronized interchange may be advantageous because it was estimated to reduce the severity of crashes due to fewer crossing conflicts, a lower speed of conflicts, and a higher time to collision. The conventional diamond was the most dangerous design based on our measures. The DDI and the synchronized interchange look like plausible substitutes for reconstructing an unsafe diamond interchange due to the similarities in their required space.
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empirical before after comparison of the operational performance of diverging and conventional diamond Interchanges
Journal of Transportation of the Institute of Transportation Engineers, 2015Co-Authors: Chunho Yeom, Bastian J Schroeder, Christopher M Cunningham, Christopher L Vaughan, Joseph E Hummer, Nagui M RouphailAbstract:A diverging diamond interchange (DDI), also known as a double crossover diamond interchange, is an unconventional interchange design. The DDI design is able to accommodate heavy left-turn demand more efficiently than conventional diamond Interchanges by switching directions of travel for the arterial through movements. The first DDI in the United States opened in 2009, with approximately 37 currently in operation and hundreds more under construction or in the planning phases. This paper presents an empirical analysis of before and after field data collected at two sites under Federal Highway Administration (FHWA) project DTFH61-10-C-00029, Field Evaluation of Double Crossover Diamond Interchanges. Operational performance data assessed in this paper include traffic volume, saturation flow rate, queue length, delay, and travel time. The study focused on the before and after evaluation of two conventional diamond Interchanges at Front Street and I-435 in Kansas City, MO, USA, and at Winton Road and I-590 in Rochester, NY, USA. The field data analysis reveals that DDIs generally operate more efficiently than their conventional diamond interchange counterparts. The Kansas City site had considerable savings in queue lengths and delays for all directional movements, while the Rochester site’s queue lengths and delays indicated somewhat mixed results, showing improvements in a specific directional movement like left turns from the arterial, but exhibiting deterioration in other, less notable movements.
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calibration and field validation of four double crossover diamond Interchanges in vissim microsimulation
Transportation Research Record, 2014Co-Authors: Bastian J Schroeder, Katayoun Salamati, Joseph E HummerAbstract:Calibration and validation results for modeling double-crossover diamond (DCD) Interchanges in a microsimulation environment are presented. The VISSIM simulation tool and detailed field data collected at four operational DCDs in the United States help to describe modeling challenges, calibration steps, and validation results in the form of delay, travel time, and queuing estimates. DCD Interchanges are rapidly being deployed across the United States, accelerated by their ability to process high volumes of especially left-turning traffic at Interchanges at a greatly reduced construction cost as that of other interchange alternatives. In the absence of an analytical methodology for evaluating these Interchanges, simulation currently represents the only option for evaluating the operational performance of DCDs. Although other research has applied simulation to DCD evaluation, this study is able to present detailed validation results from field data collected at four fully operational U.S. DCDs. The results s...
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lane utilization at two lane arterial approaches to double crossover diamond Interchanges
Transportation Research Record, 2014Co-Authors: Chunho Yeom, Bastian J Schroeder, Christopher M Cunningham, Christopher L Vaughan, Nagui M Rouphail, Joseph E HummerAbstract:Double crossover diamond (DCD) Interchanges, also known as diverging diamond Interchanges, are popular and promising alternative Interchanges that are increasingly being implemented nationwide. One unique feature of a DCD interchange is that through movements on the arterial road have to cross each other twice to complete their movements, while enabling left-turn movements from the arterial to the freeway to proceed without stopping at the downstream intersection. Consequently, Interchanges with heavy left-turn movements are good candidates for DCD implementation. This unique feature of a DCD interchange means that there is a need to research lane utilization at the upstream approach intersection of DCD Interchanges, as the lane use could be unbalanced. This unbalanced lane utilization could have a significant effect on operations at the first crossover and the interchange as a whole. This study examined lane utilization factors provided in the Highway Capacity Manual 2010 (HCM) for conventional diamond i...
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empirical study and assessment of operational performance of double crossover diamond Interchanges
Transportation Research Board 92nd Annual MeetingTransportation Research Board, 2013Co-Authors: Christopher L Vaughan, Bastian J Schroeder, Christopher M Cunningham, Joseph E HummerAbstract:Operational and safety issues at many freeway‐to‐surface street Interchanges have increased in recent years, as they are unable to handle larger traffic volumes, especially the often times heavy left‐turning demands at many Interchanges. Limitations in right‐of‐way availability, high right‐of‐way costs, and expensive bridge structures have pushed engineers to find innovative solutions to solve some of these issues. Examples of these innovative designs include the roundabout interchange, the single point urban interchange, and the double crossover diamond (DCD) interchange (also known as the diverging diamond interchange, DDI), among others. This paper provides results from the first 1.5 years of a research study commissioned by the Federal Highway Administration (FHWA) to evaluate the first few DCD installations in the United States (FHWA Project Number DTFH61‐10‐C‐00029). This paper includes summary findings on operational performance at DCD Interchanges built in recent years at I‐44 and MO‐13 in Springfield, Missouri (MO); US‐60 and National Avenue in Springfield, MO; I‐270 and Dorsett Road in Maryland Heights, MO; and US‐129 and Bessemer Street in Alcoa, Tennessee. The paper focuses mostly on the operational conditions of these Interchanges, although safety assessment, simulation analysis, and design guidance are all part of the overall project. Performance measures presented in this paper include peak‐hour queue lengths, spillback and blockage, origin‐destination travel times, signal compliance, erratic maneuvers,field‐observed conflicts, and vehicle speed profiles. The paper also includes assessments of walkability and bikeability, as well as user perceptions. The paper will provide tentative conclusions on the operational performance of DCD Interchanges to this point and will describe the program of future work planned to fully investigate the operational and safety impacts of DCDs under the aforementioned project.
Darcy M Bullock - One of the best experts on this subject based on the ideXlab platform.
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performance measures for optimizing diverging Interchanges and outcome assessment with drone video
Transportation Research Record, 2015Co-Authors: Alexander M Hainen, Amanda L Stevens, Christopher M Day, James R Sturdevant, Jamie Mackey, Matt Luker, Mark Taylor, Darcy M BullockAbstract:Diverging diamond Interchanges (DDIs) are an emerging interchange configuration that eliminates the need for left-turn phases in conventional diamonds and may be less expensive to construct than some alternative geometries. This paper examines signal timing for DDIs. DDI signal timing typically has used a two-phase configuration that reflects the two competing movements at the crossover points at each intersection of the DDI. This configuration inherently contains some inefficiency: (a) there is potential for internal queuing under two-phase configuration and (b) it is possible for the inflow demand to exceed outflow capacity of the interchange. This paper uses high-resolution event data to develop performance measures for evaluating operations at a DDI in Salt Lake City, Utah. Alternatives to the existing signal timing within the two-phase configuration are modeled and tested with a field deployment. The field deployment demonstrated the ability to prioritize ramp or through vehicles within the two-phase...
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sequence optimization at signalized diamond Interchanges using high resolution event based data
Transportation Research Record, 2015Co-Authors: Alexander M Hainen, Amanda L Stevens, Christopher M Day, James R Sturdevant, Darcy M BullockAbstract:Signalized diamond Interchanges are pairs of ramp intersections characterized by interlocked left turns and relatively close spacing. This paper describes a series of performance measures derived from high-resolution signal controller event data that can be used to optimize the internal phase sequence and offset to improve traffic flows within diamond Interchanges and to assess the progression of the interior movements qualitatively and quantitatively. The new heuristic developed in this paper improves on traditional green band optimization techniques by incorporating actual demand profiles measured in the field. A field analysis was performed on a diamond interchange at I-69 and 96th Street in northwest Indianapolis, Indiana, where the existing sequence data were collected and used to model the alternative sequences to identify the optimal sequence. Interior operations were improved under the optimized settings: the percentage of vehicle arrivals on green increased by 19% during the 09:00-to-15:00 midday...
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high resolution event based data at diamond Interchanges performance measures and optimizing ring displacement
Transportation Research Record, 2014Co-Authors: Alexander M Hainen, Amanda L Stevens, Richard S Freije, Christopher M Day, James R Sturdevant, Darcy M BullockAbstract:Signalized diamond Interchanges are unique pairs of intersections characterized by interlocked left turns and relatively close spacing between ramps. A diamond interchange has four external entry points (origins) and four external exit points (destinations). Examination of the external origin–destination paths and evaluation of their impact on the interior storage and progression are critical for operating a diamond interchange effectively. This paper describes a series of performance measures derived from high-resolution signal controller data that can be used to (a) assess the quality of progression of the interior movements qualitatively and quantitatively and (b) optimize the internal offset to improve traffic flows within the interchange. Additional performance measures for identifying internal and ramp queuing are discussed. The integration of graphical performance measures into controller front panel displays and central systems is recommended to assist engineers in tuning and maintaining efficient operation of diamond Interchanges.
Christopher M Cunningham - One of the best experts on this subject based on the ideXlab platform.
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use of microsimulation to evaluate signal phasing schemes at diverging diamond Interchanges
Transportation Research Record, 2017Co-Authors: Shannon Warchol, Thomas Chase, Christopher M CunninghamAbstract:Even though diverging diamond Interchanges (DDIs) have been the subject of research for more than a decade, the effort to standardize interchange signal timing has developed only recently. A three-factor fully crossed experiment was conducted to investigate the influence of crossover spacing and increased volumes on the performance of DDI phasing schemes. PTV Vistro software and the dynamic bandwidth assessment tool were used to optimize the split, cycle length, and offset of each of the 72 treatments. PTV Vissim software was used to collect microsimulation data. Mean interchange delay and mean stops per vehicle were selected as measures of effectiveness. Pairwise comparisons were used to determine whether an existing preferred phasing scheme could minimize delays or stops under three cases: (a) given spacing and increased volume, (b) given volume independent of spacing, and (c) given spacing independent of increased volume. The data revealed that a two- or three-critical-movement phasing scheme usually r...
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impact of exit ramp geometric treatments at diverging diamond Interchanges on queue spillback
Transportation Research Record, 2016Co-Authors: Shannon Warchol, Bastian J Schroeder, Christopher M CunninghamAbstract:Diverging diamond Interchanges (DDIs) have swept the country as an innovative interchange system since the original U.S. installation in Springfield, Missouri, in 2009. Although the DDI provides many benefits, prior research identified some operational challenges found at some of the first DDIs built around the country. This study explored the challenge of limited capacity for the right turn at the DDI ramp terminal intersection and associated queue spillback concerns that have been observed at several sites. The study investigated the impact of five geometric treatments at a DDI’s right-turn exit ramp, including a channelized turn lane with an auxiliary lane, dual right-turn lanes, right turn on red (RTOR), dual right-turn lanes with RTOR, and a slip lane. The results showed that any treatment that decreased the green-to-cycle length ratio for the right turn from the exit ramp simultaneously reduced queues at the exit ramp and the outbound through movement at the crossover. However, treatments that did n...
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lane utilization model development for diverging diamond Interchanges
Transportation Research Board 95th Annual MeetingTransportation Research Board, 2016Co-Authors: Chunho Yeom, Bastian J Schroeder, Christopher M Cunningham, Katy Salamati, Nagui M RouphailAbstract:The diverging diamond interchange (DDI: aka DCD – double crossover diamond interchange) has been a successful solution in many states, as one of the unconventional Interchanges in the U.S. since the first installation in June, 2009 in Springfield, Missouri. One of the challenges for agencies in planning and operating DDIs is to apply methodologies developed for a conventional diamond interchange. The Highway Capacity Manual 2010 provides lane utilization analysis models for various lane configurations, however there is no guarantee that these models would work for DDIs. For this reason, the authors studied a total of 11 DDIs nationwide to examine whether the current HCM lane utilization models provide accurate results for DDIs or, if the HCM models did not work, to develop new lane utilization models for DDIs. As a result of the research, unique multi-regime lane utilization models were proposed separated by the number of approach lanes and validated from the field data that were not used in the model development.
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empirical before after comparison of the operational performance of diverging and conventional diamond Interchanges
Journal of Transportation of the Institute of Transportation Engineers, 2015Co-Authors: Chunho Yeom, Bastian J Schroeder, Christopher M Cunningham, Christopher L Vaughan, Joseph E Hummer, Nagui M RouphailAbstract:A diverging diamond interchange (DDI), also known as a double crossover diamond interchange, is an unconventional interchange design. The DDI design is able to accommodate heavy left-turn demand more efficiently than conventional diamond Interchanges by switching directions of travel for the arterial through movements. The first DDI in the United States opened in 2009, with approximately 37 currently in operation and hundreds more under construction or in the planning phases. This paper presents an empirical analysis of before and after field data collected at two sites under Federal Highway Administration (FHWA) project DTFH61-10-C-00029, Field Evaluation of Double Crossover Diamond Interchanges. Operational performance data assessed in this paper include traffic volume, saturation flow rate, queue length, delay, and travel time. The study focused on the before and after evaluation of two conventional diamond Interchanges at Front Street and I-435 in Kansas City, MO, USA, and at Winton Road and I-590 in Rochester, NY, USA. The field data analysis reveals that DDIs generally operate more efficiently than their conventional diamond interchange counterparts. The Kansas City site had considerable savings in queue lengths and delays for all directional movements, while the Rochester site’s queue lengths and delays indicated somewhat mixed results, showing improvements in a specific directional movement like left turns from the arterial, but exhibiting deterioration in other, less notable movements.
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lane utilization at two lane arterial approaches to double crossover diamond Interchanges
Transportation Research Record, 2014Co-Authors: Chunho Yeom, Bastian J Schroeder, Christopher M Cunningham, Christopher L Vaughan, Nagui M Rouphail, Joseph E HummerAbstract:Double crossover diamond (DCD) Interchanges, also known as diverging diamond Interchanges, are popular and promising alternative Interchanges that are increasingly being implemented nationwide. One unique feature of a DCD interchange is that through movements on the arterial road have to cross each other twice to complete their movements, while enabling left-turn movements from the arterial to the freeway to proceed without stopping at the downstream intersection. Consequently, Interchanges with heavy left-turn movements are good candidates for DCD implementation. This unique feature of a DCD interchange means that there is a need to research lane utilization at the upstream approach intersection of DCD Interchanges, as the lane use could be unbalanced. This unbalanced lane utilization could have a significant effect on operations at the first crossover and the interchange as a whole. This study examined lane utilization factors provided in the Highway Capacity Manual 2010 (HCM) for conventional diamond i...
Bastian J Schroeder - One of the best experts on this subject based on the ideXlab platform.
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impact of exit ramp geometric treatments at diverging diamond Interchanges on queue spillback
Transportation Research Record, 2016Co-Authors: Shannon Warchol, Bastian J Schroeder, Christopher M CunninghamAbstract:Diverging diamond Interchanges (DDIs) have swept the country as an innovative interchange system since the original U.S. installation in Springfield, Missouri, in 2009. Although the DDI provides many benefits, prior research identified some operational challenges found at some of the first DDIs built around the country. This study explored the challenge of limited capacity for the right turn at the DDI ramp terminal intersection and associated queue spillback concerns that have been observed at several sites. The study investigated the impact of five geometric treatments at a DDI’s right-turn exit ramp, including a channelized turn lane with an auxiliary lane, dual right-turn lanes, right turn on red (RTOR), dual right-turn lanes with RTOR, and a slip lane. The results showed that any treatment that decreased the green-to-cycle length ratio for the right turn from the exit ramp simultaneously reduced queues at the exit ramp and the outbound through movement at the crossover. However, treatments that did n...
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lane utilization model development for diverging diamond Interchanges
Transportation Research Board 95th Annual MeetingTransportation Research Board, 2016Co-Authors: Chunho Yeom, Bastian J Schroeder, Christopher M Cunningham, Katy Salamati, Nagui M RouphailAbstract:The diverging diamond interchange (DDI: aka DCD – double crossover diamond interchange) has been a successful solution in many states, as one of the unconventional Interchanges in the U.S. since the first installation in June, 2009 in Springfield, Missouri. One of the challenges for agencies in planning and operating DDIs is to apply methodologies developed for a conventional diamond interchange. The Highway Capacity Manual 2010 provides lane utilization analysis models for various lane configurations, however there is no guarantee that these models would work for DDIs. For this reason, the authors studied a total of 11 DDIs nationwide to examine whether the current HCM lane utilization models provide accurate results for DDIs or, if the HCM models did not work, to develop new lane utilization models for DDIs. As a result of the research, unique multi-regime lane utilization models were proposed separated by the number of approach lanes and validated from the field data that were not used in the model development.
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empirical before after comparison of the operational performance of diverging and conventional diamond Interchanges
Journal of Transportation of the Institute of Transportation Engineers, 2015Co-Authors: Chunho Yeom, Bastian J Schroeder, Christopher M Cunningham, Christopher L Vaughan, Joseph E Hummer, Nagui M RouphailAbstract:A diverging diamond interchange (DDI), also known as a double crossover diamond interchange, is an unconventional interchange design. The DDI design is able to accommodate heavy left-turn demand more efficiently than conventional diamond Interchanges by switching directions of travel for the arterial through movements. The first DDI in the United States opened in 2009, with approximately 37 currently in operation and hundreds more under construction or in the planning phases. This paper presents an empirical analysis of before and after field data collected at two sites under Federal Highway Administration (FHWA) project DTFH61-10-C-00029, Field Evaluation of Double Crossover Diamond Interchanges. Operational performance data assessed in this paper include traffic volume, saturation flow rate, queue length, delay, and travel time. The study focused on the before and after evaluation of two conventional diamond Interchanges at Front Street and I-435 in Kansas City, MO, USA, and at Winton Road and I-590 in Rochester, NY, USA. The field data analysis reveals that DDIs generally operate more efficiently than their conventional diamond interchange counterparts. The Kansas City site had considerable savings in queue lengths and delays for all directional movements, while the Rochester site’s queue lengths and delays indicated somewhat mixed results, showing improvements in a specific directional movement like left turns from the arterial, but exhibiting deterioration in other, less notable movements.
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calibration and field validation of four double crossover diamond Interchanges in vissim microsimulation
Transportation Research Record, 2014Co-Authors: Bastian J Schroeder, Katayoun Salamati, Joseph E HummerAbstract:Calibration and validation results for modeling double-crossover diamond (DCD) Interchanges in a microsimulation environment are presented. The VISSIM simulation tool and detailed field data collected at four operational DCDs in the United States help to describe modeling challenges, calibration steps, and validation results in the form of delay, travel time, and queuing estimates. DCD Interchanges are rapidly being deployed across the United States, accelerated by their ability to process high volumes of especially left-turning traffic at Interchanges at a greatly reduced construction cost as that of other interchange alternatives. In the absence of an analytical methodology for evaluating these Interchanges, simulation currently represents the only option for evaluating the operational performance of DCDs. Although other research has applied simulation to DCD evaluation, this study is able to present detailed validation results from field data collected at four fully operational U.S. DCDs. The results s...
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lane utilization at two lane arterial approaches to double crossover diamond Interchanges
Transportation Research Record, 2014Co-Authors: Chunho Yeom, Bastian J Schroeder, Christopher M Cunningham, Christopher L Vaughan, Nagui M Rouphail, Joseph E HummerAbstract:Double crossover diamond (DCD) Interchanges, also known as diverging diamond Interchanges, are popular and promising alternative Interchanges that are increasingly being implemented nationwide. One unique feature of a DCD interchange is that through movements on the arterial road have to cross each other twice to complete their movements, while enabling left-turn movements from the arterial to the freeway to proceed without stopping at the downstream intersection. Consequently, Interchanges with heavy left-turn movements are good candidates for DCD implementation. This unique feature of a DCD interchange means that there is a need to research lane utilization at the upstream approach intersection of DCD Interchanges, as the lane use could be unbalanced. This unbalanced lane utilization could have a significant effect on operations at the first crossover and the interchange as a whole. This study examined lane utilization factors provided in the Highway Capacity Manual 2010 (HCM) for conventional diamond i...
Alexander M Hainen - One of the best experts on this subject based on the ideXlab platform.
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performance measures for optimizing diverging Interchanges and outcome assessment with drone video
Transportation Research Record, 2015Co-Authors: Alexander M Hainen, Amanda L Stevens, Christopher M Day, James R Sturdevant, Jamie Mackey, Matt Luker, Mark Taylor, Darcy M BullockAbstract:Diverging diamond Interchanges (DDIs) are an emerging interchange configuration that eliminates the need for left-turn phases in conventional diamonds and may be less expensive to construct than some alternative geometries. This paper examines signal timing for DDIs. DDI signal timing typically has used a two-phase configuration that reflects the two competing movements at the crossover points at each intersection of the DDI. This configuration inherently contains some inefficiency: (a) there is potential for internal queuing under two-phase configuration and (b) it is possible for the inflow demand to exceed outflow capacity of the interchange. This paper uses high-resolution event data to develop performance measures for evaluating operations at a DDI in Salt Lake City, Utah. Alternatives to the existing signal timing within the two-phase configuration are modeled and tested with a field deployment. The field deployment demonstrated the ability to prioritize ramp or through vehicles within the two-phase...
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sequence optimization at signalized diamond Interchanges using high resolution event based data
Transportation Research Record, 2015Co-Authors: Alexander M Hainen, Amanda L Stevens, Christopher M Day, James R Sturdevant, Darcy M BullockAbstract:Signalized diamond Interchanges are pairs of ramp intersections characterized by interlocked left turns and relatively close spacing. This paper describes a series of performance measures derived from high-resolution signal controller event data that can be used to optimize the internal phase sequence and offset to improve traffic flows within diamond Interchanges and to assess the progression of the interior movements qualitatively and quantitatively. The new heuristic developed in this paper improves on traditional green band optimization techniques by incorporating actual demand profiles measured in the field. A field analysis was performed on a diamond interchange at I-69 and 96th Street in northwest Indianapolis, Indiana, where the existing sequence data were collected and used to model the alternative sequences to identify the optimal sequence. Interior operations were improved under the optimized settings: the percentage of vehicle arrivals on green increased by 19% during the 09:00-to-15:00 midday...
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high resolution event based data at diamond Interchanges performance measures and optimizing ring displacement
Transportation Research Record, 2014Co-Authors: Alexander M Hainen, Amanda L Stevens, Richard S Freije, Christopher M Day, James R Sturdevant, Darcy M BullockAbstract:Signalized diamond Interchanges are unique pairs of intersections characterized by interlocked left turns and relatively close spacing between ramps. A diamond interchange has four external entry points (origins) and four external exit points (destinations). Examination of the external origin–destination paths and evaluation of their impact on the interior storage and progression are critical for operating a diamond interchange effectively. This paper describes a series of performance measures derived from high-resolution signal controller data that can be used to (a) assess the quality of progression of the interior movements qualitatively and quantitatively and (b) optimize the internal offset to improve traffic flows within the interchange. Additional performance measures for identifying internal and ramp queuing are discussed. The integration of graphical performance measures into controller front panel displays and central systems is recommended to assist engineers in tuning and maintaining efficient operation of diamond Interchanges.
