Darcy Bullock - Academia.edu (original) (raw)
Papers by Darcy Bullock
In 2003 the Indiana Department of Transportation (INDOT) executed an ambitious interstate reconst... more In 2003 the Indiana Department of Transportation (INDOT) executed an ambitious interstate reconstruction project in Indianapolis, named Hyperfix. This project completely closed the I-65/70 section during reconstruction, on which approximately 250,000 vehicles travel daily. Due to the scope and risk involved, an extensive amount of planning, coordination, and cooperation occurred. The main section was rebuilt during the total closure phase, which lasted 55 days. The total closure approach had never been performed before by INDOT on such a high volume artery in a downtown metropolitan area. This present study analyzed the project and its impact on the Indianapolis area. The report includes findings on planning and design issues, contractor and INDOT operations, traffic impact, business impact, the park and ride service implemented, and other issues related to total closure.
Remote Sensing
Lane markings are one of the essential elements of road information, which is useful for a wide r... more Lane markings are one of the essential elements of road information, which is useful for a wide range of transportation applications. Several studies have been conducted to extract lane markings through intensity thresholding of Light Detection and Ranging (LiDAR) point clouds acquired by mobile mapping systems (MMS). This paper proposes an intensity thresholding strategy using unsupervised intensity normalization and a deep learning strategy using automatically labeled training data for lane marking extraction. For comparative evaluation, original intensity thresholding and deep learning using manually established labels strategies are also implemented. A pavement surface-based assessment of lane marking extraction by the four strategies is conducted in asphalt and concrete pavement areas covered by MMS equipped with multiple LiDAR scanners. Additionally, the extracted lane markings are used for lane width estimation and reporting lane marking gaps along various highways. The norma...
International Journal of Aviation, Aeronautics, and Aerospace, 2016
Journal of Transportation Engineering, Oct 1, 2011
ABSTRACT Travel time has long been an important performance measure for assessing traffic conditi... more ABSTRACT Travel time has long been an important performance measure for assessing traffic conditions and the extent of highway congestion. However, recently, more and more attention has been given to understanding the uncertainty regarding the variability in travel time from hour to hour and day to day-variability that is known to be a source of great frustration among road users. In this paper, travel-time variability is studied by collecting travel-time data using probe data on freeway segments in Indianapolis obtained using anonymous Bluetooth sampling techniques. The data show considerable travel-time variability is induced by adverse weather, but also show that variability results from unexpected changes in traffic flow rates and driver behavior. Various statistical models are estimated to understand the effect that traffic-related variables have on variability in individual vehicle travel times as well as average travel times. For individual vehicle travel times, a model is estimated to study how the probability of a vehicle's duration of time spent on freeway segments changes over time. Interestingly, this model shows that the point where the conditional probability of travel times becoming longer occurs roughly at the onset of level-of-service F conditions-an important finding that supports the traffic-density definitions of level of service F used in the highway capacity manual. Another model, estimated using seemingly unrelated regression estimation, studies 15-min interval average vehicle travel times and the standard deviation of these travel times on the basis of speed and volume (available from remote traffic microwave sensors) and time of day indicators. This model provides interesting insights into the traffic parameters that affect average travel time and its variability. DOI: 10.1061/(ASCE)TE.1943-5436.0000253. (C) 2011 American Society of Civil Engineers.
This audio was recorded from Citizen Band (CB) radio traffic on Channel 19 adjacent to mile marke... more This audio was recorded from Citizen Band (CB) radio traffic on Channel 19 adjacent to mile marker 127.8 on I-65 in Indiana (Latitude 39.918554, Longitude -86.329367). The audio recording represents selected transmissions recorded at approximately 9:30am on 21 July 2010 ...
Transportation Research Record Journal of the Transportation Research Board, Dec 1, 2009
Weigh-in-motion (WIM) sensors are being used by state agencies for commercial vehicle weight enfo... more Weigh-in-motion (WIM) sensors are being used by state agencies for commercial vehicle weight enforcement applications that require a high level of accuracy for determining individual vehicle weights. Existing methods of evaluating WIM weight data accuracy have not been effective for detecting small but consistent calibration drifts. This paper proposes the use of a left–right differential metric that is computed as a percentage difference between the left and right wheel weights on the steer axle of Class 9 trucks for WIM sensors that measure and report individual left and right wheel weights. In this paper, the left–right differential is monitored over time by using statistical process control charts to identify when sensors are exhibiting statistically significant variations. The monitoring procedure can be integrated into existing quality control programs. Data from WIM sites in Indiana and California were used to evaluate the effectiveness of this metric.
Automated Traffic Signal Performance Measure Workshop, 2016
This study analyzed the impact emergency vehicle traffic signal preemption had on the travel time... more This study analyzed the impact emergency vehicle traffic signal preemption had on the travel time and delay of traffic on a signalized corridor in Northern Virginia. The corridor was composed of three coordinated intersections on Route 7 (Leesburg Pike near Landsdowne). The motivation for this work was the construction of a new hospital, which opened near the study area. Emergency response personnel expressed an interest in deploying a preemption system that would aid ambulances in quickly and safely reaching the hospital. The Virginia Department of Transportation (VDOT) was interested in quantifying the effects that the proposed signal preemption would have on Route 7 traffic, particularly during the morning rush hour, when inbound traffic, towards Washington, D.C., is quite heavy. This information could then be used to make an informed decision regarding the deployment of an emergency vehicle preemption system. The study was conducted in the FHWA's Traffic Research Laboratory (TReL) using a Controller Interface Device (CID). The CID was used to interface a modified version of the CORSIM simulation model with Type 170 controllers supplied by VDOT. The Type 170 controllers were programmed with the identical signal plans that exist at the study intersections, with minor modifications to provide the proposed signal preemption. In this carefully controlled hardware-in-the-loop environment, CORSIM provided the microscopic simulation and tabulation of measures of effectiveness (MOE's), but instead of CORSIM emulating controller features, the simulation package sent detector information to the physical controllers and read-back phase indicators. Since CORSIM tabulates performance MOE's, quantitative results with and without preemption measurements were obtained. Several ambulance routes, each with multiple runs, were analyzed. The results were aggregated and interpreted. Although several of the preemption cases had "statistically significant different means" when compared to the base case (no preemption), the biggest increase in average
Transportation Research Record Journal of the Transportation Research Board, 2009
Transportation Research Record Journal of the Transportation Research Board, Feb 3, 2015
Transportation Research Record, 1999
... CESAR A. QUIROGA AND DARCY BULLOCK ... time period should comply with specific error toleranc... more ... CESAR A. QUIROGA AND DARCY BULLOCK ... time period should comply with specific error tolerance specifications in the computation of the mean speed (6). Each run results in a GPS file that contains time, speed, and coordinate data at regular time intervals, say, every 1 s. To ...
Transportation Research Record Journal of the Transportation Research Board, Dec 1, 2010
An anonymous Bluetooth tracking system was deployed at the new Indianapolis International Airport... more An anonymous Bluetooth tracking system was deployed at the new Indianapolis International Airport in Indiana from May 8 to June 2, 2009, to measure the time for passengers (a) to move from the nonsterile side of the airport (presecurity), (b) to clear the security screening checkpoint, and (c) to enter the walkway to Concourse B on the sterile side. The maximum passenger transit time between these checkpoints was observed on Monday mornings at approximately 0600, when it could take passengers up to 20 min to transit the security queue and screening and to walk to Concourse B. Depending on the day of the week, this approach was demonstrated to sample between 5% and 6.8% of passengers. This modest sample size provides a more robust measurement of screening times than the current system of manually distributing time-stamped cards as passengers enter the queue and collecting them where passengers pass through the magnetometer. Furthermore, because the final passenger reference point used in this study is on the sterile concourse, it captures the time associated with passengers repackaging their belongings and redonning their shoes. The data from this pilot study suggest the feasibility of using an automated system to provide quantitative information to managers for more effective allocation of scarce resources, as well as providing the traveling public with necessary information about the amount of time they should allocate for transiting the security screening process. The paper concludes by suggesting that additional pilot studies should be performed at several airports with alternative checkpoint configurations to develop a consensus on best practices for locating sensors to measure passage times at airport security screening.
Transportation Research Record Journal of the Transportation Research Board, 2011
The configuration of a single controller in a coordinated arterial signal system requires the pro... more The configuration of a single controller in a coordinated arterial signal system requires the programming of approximately 250 parameters ranging from minimum green times to complex hardware-specific settings that determine how unused green time is allocated to competing phases. When this parameter count is extrapolated to a 10-intersection arterial (2,500 parameters), one or more data entry errors are likely to occur and must be identified and corrected. Ensuring that the resulting coordinated signal system operates as designed requires an exceptionally high level of expertise to confirm by visual field observations and a perhaps unattainable level of expertise in verification by inspection of data entry screens in an office. There is a clear need for visualization tools to provide educational insight into how coordinated signal systems should be expected to operate under different parameter settings and to document coordinated system behavior. In this paper a series of graphics was developed to visualize coordinated system operation characteristics such as time-of-day schedule change time, observed cycle length, green time and split time, coordinated phase actuation, early return to green, arrivals over advance detection relative to green indication, progression quality characteristics related to offset, adjacent signal synchronization, coordinated phase operation in rest, plan time changes, preemption, impact of queuing, and longitudinal analysis of splits. These graphics can be used as a new learning tool, as well as a visual feedback tool to confirm that a coordinated system is operating as expected.
Transportation Research Record Journal of the Transportation Research Board, 2011
Various control algorithms process vehicle detector on and off times with the objective of quanti... more Various control algorithms process vehicle detector on and off times with the objective of quantifying split performance. Two such metrics are green occupancy ratio (GOR) and volume-to-capacity (v/c) ratio, both of which can be used to estimate the efficiency of a split as well as estimate oversaturated conditions. The GOR metric is attractive because of its simplicity of implementation; the v/c ratio is based on well-established traffic flow concepts and is independent of detector geometry although additional processing is required to develop the metric. Characterizing the impact of detection zone length and vehicle speed on the GOR as well as comparing its performance with another metric is important in understanding the robustness of GOR as a surrogate performance metric. This paper analyzes the difference between calculated GOR and v/c ratios over different detection zone lengths and differing vehicle speeds, compares these values with a calculated delay metric, and observes the effectiveness of GOR as an indicator of oversaturation. On the basis of the analysis, the paper documents the influence of approach speed and detection zone length on the calculated GOR metric. The paper concludes that the GOR values tend to reach a saturated value of 1.0 more rapidly than v/c, making it challenging for the analyst to identify oversaturated conditions by the metric alone. For practitioners using the GOR metric, it is critical that the system be calibrated properly because of the sensitivity of GOR to the detection zone length and vehicle speed. However, because direct measurement of v/c is difficult to obtain, GOR may still be a reasonable surrogate in real-time performance assessment of traffic signal systems.
Transportation Research Record Journal of the Transportation Research Board, Feb 3, 2015
Managing the transportation system requires balancing the needs of many users and multiple transp... more Managing the transportation system requires balancing the needs of many users and multiple transportation modes. Historically, traffic engineers have relied upon short term engineering studies and intuition to manage traffic signal systems. There is broad consensus in the traffic engineering community that real-time performance measures would enable better operations. This paper presents motivation and means to provide real-time pedestrian performance measures using existing controller and vehicle detection technology. Applicable pedestrian service models are identified and procedures to collect data for pedestrian performance measures are recommended. The resulting pedestrian performance measures can be presented in an easy to interpret visual format that provides a valuable tool for assessing and comparing pedestrian service. Pedestrian service may be compared at different crosswalks in the jurisdiction for prioritization purposes, or at the same crosswalk under different conditions. The proposed pedestrian performance measures may be used in conjunction with existing vehicle performance measures, resulting in an integrated approach to assessing level of service for both vehicles and pedestrians under different conditions and for different signal timing plans.
In 2003 the Indiana Department of Transportation (INDOT) executed an ambitious interstate reconst... more In 2003 the Indiana Department of Transportation (INDOT) executed an ambitious interstate reconstruction project in Indianapolis, named Hyperfix. This project completely closed the I-65/70 section during reconstruction, on which approximately 250,000 vehicles travel daily. Due to the scope and risk involved, an extensive amount of planning, coordination, and cooperation occurred. The main section was rebuilt during the total closure phase, which lasted 55 days. The total closure approach had never been performed before by INDOT on such a high volume artery in a downtown metropolitan area. This present study analyzed the project and its impact on the Indianapolis area. The report includes findings on planning and design issues, contractor and INDOT operations, traffic impact, business impact, the park and ride service implemented, and other issues related to total closure.
Remote Sensing
Lane markings are one of the essential elements of road information, which is useful for a wide r... more Lane markings are one of the essential elements of road information, which is useful for a wide range of transportation applications. Several studies have been conducted to extract lane markings through intensity thresholding of Light Detection and Ranging (LiDAR) point clouds acquired by mobile mapping systems (MMS). This paper proposes an intensity thresholding strategy using unsupervised intensity normalization and a deep learning strategy using automatically labeled training data for lane marking extraction. For comparative evaluation, original intensity thresholding and deep learning using manually established labels strategies are also implemented. A pavement surface-based assessment of lane marking extraction by the four strategies is conducted in asphalt and concrete pavement areas covered by MMS equipped with multiple LiDAR scanners. Additionally, the extracted lane markings are used for lane width estimation and reporting lane marking gaps along various highways. The norma...
International Journal of Aviation, Aeronautics, and Aerospace, 2016
Journal of Transportation Engineering, Oct 1, 2011
ABSTRACT Travel time has long been an important performance measure for assessing traffic conditi... more ABSTRACT Travel time has long been an important performance measure for assessing traffic conditions and the extent of highway congestion. However, recently, more and more attention has been given to understanding the uncertainty regarding the variability in travel time from hour to hour and day to day-variability that is known to be a source of great frustration among road users. In this paper, travel-time variability is studied by collecting travel-time data using probe data on freeway segments in Indianapolis obtained using anonymous Bluetooth sampling techniques. The data show considerable travel-time variability is induced by adverse weather, but also show that variability results from unexpected changes in traffic flow rates and driver behavior. Various statistical models are estimated to understand the effect that traffic-related variables have on variability in individual vehicle travel times as well as average travel times. For individual vehicle travel times, a model is estimated to study how the probability of a vehicle's duration of time spent on freeway segments changes over time. Interestingly, this model shows that the point where the conditional probability of travel times becoming longer occurs roughly at the onset of level-of-service F conditions-an important finding that supports the traffic-density definitions of level of service F used in the highway capacity manual. Another model, estimated using seemingly unrelated regression estimation, studies 15-min interval average vehicle travel times and the standard deviation of these travel times on the basis of speed and volume (available from remote traffic microwave sensors) and time of day indicators. This model provides interesting insights into the traffic parameters that affect average travel time and its variability. DOI: 10.1061/(ASCE)TE.1943-5436.0000253. (C) 2011 American Society of Civil Engineers.
This audio was recorded from Citizen Band (CB) radio traffic on Channel 19 adjacent to mile marke... more This audio was recorded from Citizen Band (CB) radio traffic on Channel 19 adjacent to mile marker 127.8 on I-65 in Indiana (Latitude 39.918554, Longitude -86.329367). The audio recording represents selected transmissions recorded at approximately 9:30am on 21 July 2010 ...
Transportation Research Record Journal of the Transportation Research Board, Dec 1, 2009
Weigh-in-motion (WIM) sensors are being used by state agencies for commercial vehicle weight enfo... more Weigh-in-motion (WIM) sensors are being used by state agencies for commercial vehicle weight enforcement applications that require a high level of accuracy for determining individual vehicle weights. Existing methods of evaluating WIM weight data accuracy have not been effective for detecting small but consistent calibration drifts. This paper proposes the use of a left–right differential metric that is computed as a percentage difference between the left and right wheel weights on the steer axle of Class 9 trucks for WIM sensors that measure and report individual left and right wheel weights. In this paper, the left–right differential is monitored over time by using statistical process control charts to identify when sensors are exhibiting statistically significant variations. The monitoring procedure can be integrated into existing quality control programs. Data from WIM sites in Indiana and California were used to evaluate the effectiveness of this metric.
Automated Traffic Signal Performance Measure Workshop, 2016
This study analyzed the impact emergency vehicle traffic signal preemption had on the travel time... more This study analyzed the impact emergency vehicle traffic signal preemption had on the travel time and delay of traffic on a signalized corridor in Northern Virginia. The corridor was composed of three coordinated intersections on Route 7 (Leesburg Pike near Landsdowne). The motivation for this work was the construction of a new hospital, which opened near the study area. Emergency response personnel expressed an interest in deploying a preemption system that would aid ambulances in quickly and safely reaching the hospital. The Virginia Department of Transportation (VDOT) was interested in quantifying the effects that the proposed signal preemption would have on Route 7 traffic, particularly during the morning rush hour, when inbound traffic, towards Washington, D.C., is quite heavy. This information could then be used to make an informed decision regarding the deployment of an emergency vehicle preemption system. The study was conducted in the FHWA's Traffic Research Laboratory (TReL) using a Controller Interface Device (CID). The CID was used to interface a modified version of the CORSIM simulation model with Type 170 controllers supplied by VDOT. The Type 170 controllers were programmed with the identical signal plans that exist at the study intersections, with minor modifications to provide the proposed signal preemption. In this carefully controlled hardware-in-the-loop environment, CORSIM provided the microscopic simulation and tabulation of measures of effectiveness (MOE's), but instead of CORSIM emulating controller features, the simulation package sent detector information to the physical controllers and read-back phase indicators. Since CORSIM tabulates performance MOE's, quantitative results with and without preemption measurements were obtained. Several ambulance routes, each with multiple runs, were analyzed. The results were aggregated and interpreted. Although several of the preemption cases had "statistically significant different means" when compared to the base case (no preemption), the biggest increase in average
Transportation Research Record Journal of the Transportation Research Board, 2009
Transportation Research Record Journal of the Transportation Research Board, Feb 3, 2015
Transportation Research Record, 1999
... CESAR A. QUIROGA AND DARCY BULLOCK ... time period should comply with specific error toleranc... more ... CESAR A. QUIROGA AND DARCY BULLOCK ... time period should comply with specific error tolerance specifications in the computation of the mean speed (6). Each run results in a GPS file that contains time, speed, and coordinate data at regular time intervals, say, every 1 s. To ...
Transportation Research Record Journal of the Transportation Research Board, Dec 1, 2010
An anonymous Bluetooth tracking system was deployed at the new Indianapolis International Airport... more An anonymous Bluetooth tracking system was deployed at the new Indianapolis International Airport in Indiana from May 8 to June 2, 2009, to measure the time for passengers (a) to move from the nonsterile side of the airport (presecurity), (b) to clear the security screening checkpoint, and (c) to enter the walkway to Concourse B on the sterile side. The maximum passenger transit time between these checkpoints was observed on Monday mornings at approximately 0600, when it could take passengers up to 20 min to transit the security queue and screening and to walk to Concourse B. Depending on the day of the week, this approach was demonstrated to sample between 5% and 6.8% of passengers. This modest sample size provides a more robust measurement of screening times than the current system of manually distributing time-stamped cards as passengers enter the queue and collecting them where passengers pass through the magnetometer. Furthermore, because the final passenger reference point used in this study is on the sterile concourse, it captures the time associated with passengers repackaging their belongings and redonning their shoes. The data from this pilot study suggest the feasibility of using an automated system to provide quantitative information to managers for more effective allocation of scarce resources, as well as providing the traveling public with necessary information about the amount of time they should allocate for transiting the security screening process. The paper concludes by suggesting that additional pilot studies should be performed at several airports with alternative checkpoint configurations to develop a consensus on best practices for locating sensors to measure passage times at airport security screening.
Transportation Research Record Journal of the Transportation Research Board, 2011
The configuration of a single controller in a coordinated arterial signal system requires the pro... more The configuration of a single controller in a coordinated arterial signal system requires the programming of approximately 250 parameters ranging from minimum green times to complex hardware-specific settings that determine how unused green time is allocated to competing phases. When this parameter count is extrapolated to a 10-intersection arterial (2,500 parameters), one or more data entry errors are likely to occur and must be identified and corrected. Ensuring that the resulting coordinated signal system operates as designed requires an exceptionally high level of expertise to confirm by visual field observations and a perhaps unattainable level of expertise in verification by inspection of data entry screens in an office. There is a clear need for visualization tools to provide educational insight into how coordinated signal systems should be expected to operate under different parameter settings and to document coordinated system behavior. In this paper a series of graphics was developed to visualize coordinated system operation characteristics such as time-of-day schedule change time, observed cycle length, green time and split time, coordinated phase actuation, early return to green, arrivals over advance detection relative to green indication, progression quality characteristics related to offset, adjacent signal synchronization, coordinated phase operation in rest, plan time changes, preemption, impact of queuing, and longitudinal analysis of splits. These graphics can be used as a new learning tool, as well as a visual feedback tool to confirm that a coordinated system is operating as expected.
Transportation Research Record Journal of the Transportation Research Board, 2011
Various control algorithms process vehicle detector on and off times with the objective of quanti... more Various control algorithms process vehicle detector on and off times with the objective of quantifying split performance. Two such metrics are green occupancy ratio (GOR) and volume-to-capacity (v/c) ratio, both of which can be used to estimate the efficiency of a split as well as estimate oversaturated conditions. The GOR metric is attractive because of its simplicity of implementation; the v/c ratio is based on well-established traffic flow concepts and is independent of detector geometry although additional processing is required to develop the metric. Characterizing the impact of detection zone length and vehicle speed on the GOR as well as comparing its performance with another metric is important in understanding the robustness of GOR as a surrogate performance metric. This paper analyzes the difference between calculated GOR and v/c ratios over different detection zone lengths and differing vehicle speeds, compares these values with a calculated delay metric, and observes the effectiveness of GOR as an indicator of oversaturation. On the basis of the analysis, the paper documents the influence of approach speed and detection zone length on the calculated GOR metric. The paper concludes that the GOR values tend to reach a saturated value of 1.0 more rapidly than v/c, making it challenging for the analyst to identify oversaturated conditions by the metric alone. For practitioners using the GOR metric, it is critical that the system be calibrated properly because of the sensitivity of GOR to the detection zone length and vehicle speed. However, because direct measurement of v/c is difficult to obtain, GOR may still be a reasonable surrogate in real-time performance assessment of traffic signal systems.
Transportation Research Record Journal of the Transportation Research Board, Feb 3, 2015
Managing the transportation system requires balancing the needs of many users and multiple transp... more Managing the transportation system requires balancing the needs of many users and multiple transportation modes. Historically, traffic engineers have relied upon short term engineering studies and intuition to manage traffic signal systems. There is broad consensus in the traffic engineering community that real-time performance measures would enable better operations. This paper presents motivation and means to provide real-time pedestrian performance measures using existing controller and vehicle detection technology. Applicable pedestrian service models are identified and procedures to collect data for pedestrian performance measures are recommended. The resulting pedestrian performance measures can be presented in an easy to interpret visual format that provides a valuable tool for assessing and comparing pedestrian service. Pedestrian service may be compared at different crosswalks in the jurisdiction for prioritization purposes, or at the same crosswalk under different conditions. The proposed pedestrian performance measures may be used in conjunction with existing vehicle performance measures, resulting in an integrated approach to assessing level of service for both vehicles and pedestrians under different conditions and for different signal timing plans.