WZ-speed harmonizer: an optimized active traffic and demand management system with speed harmonization for work zones

Speed harmonization, known as Variable Speed Limit (VSL), is implemented through a number of Changeable Message Signs (CMSs) spaced out over a stretch of highway. The CMSs display advisory speeds that may change over time and space to regulate travel speed and arrival time to a highway bottleneck and consequently reduce congestion impacts. Usually speed harmonization studies determine optimal dynamic advisory speeds to minimize travel time and delay. Delay and travel time can be further minimized if optimal location and number of CMSs are determined as well. Determining dynamic advisory speeds depends on the number and locations of CMSs; thus these variables have to be optimized simultaneously. This study is the first study which simultaneously optimized 1) dynamic advisory speeds, 2) number of CMSs, and 3) location of the CMSs to minimize total travel time and a penalty function for the number of CMSs. This problem is important as it reduces maintenance and installation costs of CMSs and enhances effectiveness of speed harmonization to reduce congestion impacts such as delay. Solving this problem is challenging because it is a large scale Mixed Integer Nonlinear Program (MINLP). Determining traffic speed and extend of queue is critical to develop a speed harmonization scheme to mitigate congestion. Past studies have used first order model or second order model as a constraint in the optimization program to determine speed and extend of queue. This study compared the first order model and the second order model versus field data and showed that the second order model was better in estimating average queue length and maximum queue length. To use the second order mode, it is necessary to calibrate the model parameters, which are relaxation time (τ) and anticipation coefficient (ϑ). This study calibrated the parameters using work zone field data to minimize error in speed and queue length estimates. The calibration is a complex process since there might be many local optimal points returning parameter values that are not physically justifiable. To overcome this issue, this study proposed a new calibration procedure. The methodology detected the behavior of the second order model in the τ- ϑ space and determined a search direction and its boundaries to avoid stopping at local minima. Although the second order model returned acceptable average and maximum queue lengths, it returned slower queue propagation pattern and faster queue dissipation pattern than field data. Thus the two- ϑ model was proposed to more maturely reflect asymmetric queue propagation and dissipation. The modification considered two different anticipation coefficients for queue propagation (ϑ_p) and queue shrinkage (ϑ_s). The two- ϑ model was calibrated using field data and results showed that the ratio of ϑ_s/ϑ_p ranges from 1.86 to 2.6 and both of them are greater than single ϑ. The solutions for the optimization program mainly tackled integrality. One source of integrality is piecewise speed-density models. Previous studies have used single-regime (single piece) models, but these models are not generally sufficient to describe congested conditions. Thus this study included the piecewise models as constraints to enhance accuracy of traffic state prediction in congested conditions. A continuous transformation approach was proposed to eliminate relevant integer variables. The methodology was used to optimize speed harmonization for a 12.5-mile roadway and a 50-min analysis duration where locations of the CMSs were given. For this problem, the methodology eliminated 30,000 binary variables and solved the problem in 23 minutes when the program included roughly 158,000 variables and 186,000 constraints. The results showed that WZSH can reduce delay by 15.7% and maximum queue length by 37.5% compared to the no speed harmonization condition. Another source of integrality is binary variables to determine location and number of CMSs. To solve the problem, three solution methods were proposed: 1) Greedy algorithm, 2) Augmented-Cut and Branch (AC&B) method, and 3) Approximate Decomposition method. The three solution methods were compared using a benchmark problem and results showed that the three methods return very close objective function values (within 1%), but the Approximate Decomposition method requires less computational resources. In particular, the Approximate Decomposition method reduced the number of WZSH solution by factors of 14.1 and 6.6 compared with Greedy Algorithm and AC&B method, respectively

WorkZoneQ User Guide for Two-Lane Freeway Work Zones

WorkZoneQ was developed in Visual Basic for Applications (VBA) to implement the results of the previous study, “Queue and Users’ Costs in Highway Work Zones.” This report contains the WorkZoneQ user guide. WorkZoneQ consists of eight Excel worksheets and input data are traffic information, geometric characteristics, traffic control plan, and value of time figures. Then WorkZoneQ determines the capacity and computes queue length, delay, users’ costs, and congestion duration. It also determines the intervals that do not satisfy IDOT mobility standards. Eight example problems were solved. The first one is a basic example to obtain the above output data. The successive examples show the capability of the program to handle different time interval lengths, variation of volume within the interval, flagger presence, police presence, change in work intensity, temporary roadway blockage, and different speed limits. Three workshops were conducted for IDOT engineers and their feedback was used to further improve the program. The current version of the program was developed using field data collected from 2-to-1 freeway work zones and it is recommended that a future project expand the program for other lane configurations.Illinois Department of Transportation R27-110published or submitted for publicationnot peer reviewe

The global burden of adolescent and young adult cancer in 2019 : a systematic analysis for the Global Burden of Disease Study 2019

Background In estimating the global burden of cancer, adolescents and young adults with cancer are often overlooked, despite being a distinct subgroup with unique epidemiology, clinical care needs, and societal impact. Comprehensive estimates of the global cancer burden in adolescents and young adults (aged 15-39 years) are lacking. To address this gap, we analysed results from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019, with a focus on the outcome of disability-adjusted life-years (DALYs), to inform global cancer control measures in adolescents and young adults. Methods Using the GBD 2019 methodology, international mortality data were collected from vital registration systems, verbal autopsies, and population-based cancer registry inputs modelled with mortality-to-incidence ratios (MIRs). Incidence was computed with mortality estimates and corresponding MIRs. Prevalence estimates were calculated using modelled survival and multiplied by disability weights to obtain years lived with disability (YLDs). Years of life lost (YLLs) were calculated as age-specific cancer deaths multiplied by the standard life expectancy at the age of death. The main outcome was DALYs (the sum of YLLs and YLDs). Estimates were presented globally and by Socio-demographic Index (SDI) quintiles (countries ranked and divided into five equal SDI groups), and all estimates were presented with corresponding 95% uncertainty intervals (UIs). For this analysis, we used the age range of 15-39 years to define adolescents and young adults. Findings There were 1.19 million (95% UI 1.11-1.28) incident cancer cases and 396 000 (370 000-425 000) deaths due to cancer among people aged 15-39 years worldwide in 2019. The highest age-standardised incidence rates occurred in high SDI (59.6 [54.5-65.7] per 100 000 person-years) and high-middle SDI countries (53.2 [48.8-57.9] per 100 000 person-years), while the highest age-standardised mortality rates were in low-middle SDI (14.2 [12.9-15.6] per 100 000 person-years) and middle SDI (13.6 [12.6-14.8] per 100 000 person-years) countries. In 2019, adolescent and young adult cancers contributed 23.5 million (21.9-25.2) DALYs to the global burden of disease, of which 2.7% (1.9-3.6) came from YLDs and 97.3% (96.4-98.1) from YLLs. Cancer was the fourth leading cause of death and tenth leading cause of DALYs in adolescents and young adults globally. Interpretation Adolescent and young adult cancers contributed substantially to the overall adolescent and young adult disease burden globally in 2019. These results provide new insights into the distribution and magnitude of the adolescent and young adult cancer burden around the world. With notable differences observed across SDI settings, these estimates can inform global and country-level cancer control efforts. Copyright (C) 2021 The Author(s). Published by Elsevier Ltd.Peer reviewe

Traffic Flow Characteristics and Capacity in Police-enforced and Intelligent Work Zones

AbstractThe effects of police enforcement on vehicle speeds in freeway work zones were examined in several studies. Likewise, many past studies investigated the effects of ITS implementation on vehicle speeds in freeway work zones. However, the effects of police enforcement and ITS implementation on work zone traffic flow characteristics and capacity have not yet been extensively studied. Hence, this study investigates the distinct effects of police enforcement and ITS implementation on work zone speedflow curve and capacity. Three sets of traffic data were collected in a two-lane-open work zone located on I-55 near Chicago. The first data set was collected when there was only the traditional Manual of Uniform Traffic Control Devices (MUTCD) signage in the work zone. The second and the third data sets were collected when there was additionally police enforcement and Speed Photo Enforcement (SPE) in the work zone, respectively.The results showed that both the police enforcement and SPE led to significant changes in the work zone speed-flow curve compared to only MUTCD signage conditions. The general shape of the speed-flow relationship inside the work zone was similar to the speed-flow curve under basic freeway conditions, but the bending point of the upper branch of the curve occurred at lower traffic flow rates and the rate of the decrease in speed was higher. The speed-flow curve for the MUTCD signage-only casereturned a work zone capacity of around 1,850 passenger cars per hour per lane (pcphpl). Compared to that speed-flow curve, both the police enforcement and SPE moved the upper (uncongested) branch of the speed-flow curve downward, which caused a work zone capacity reduction of about 50 pcphpl in the case of police enforcement and 100 pcphpl in the case of SPE implementation.The results obtained through this study reveals the distinct effects of police enforcement and ITS on work zone capacity. Accurately estimating the capacity of work zones with different speed reduction treatments provides more efficient operation in a real-time system, more accurate diversion and traveler information for alternate routing, improved reliability of the system, and better understanding of the traffic flow characteristics in work zones. © 2011 Published by Elsevier Ltd

Queue And User's Costs In Highway Work Zones

The IDOT Bureau of Design and Environment (BDE) Manual requires that traffic control plans for freeway reconstruction projects include a queuing analysis to determine the anticipated traffic backups in work zones. Queue length and delay calculations rely on the estimation of capacity and operating speed. In this study, field data were collected from five work zones in Illinois. Thirteen data sets were extracted from the field data. Each data set represents a particular traffic condition at a given site. A work zone capacity value was suggested for each traffic condition based on the field data. The suggested capacity for the sites with speed limit of 45 mph ranges from 1200 pcphpl (passenger cars per hour per lane) to 1550 pcphpl. The 1200 value was suggested for a traffic condition with flagger and queue, and 1550 value was for a traffic condition with no work activity, no speed management treatment and no queue. A capacity of 1600 pcphpl was suggested for a site with speed limit of 55 mph, dynamic speed feedback sign, no work activity, and no queue; and a capacity value of 1750 pcphplwas recommended for a short-distance work zone with speed limit of 55 mph, no work activity, and no queue. Using the field data, speed-flow curves were proposed for: work zones with speed limit of 45 mph and a flagger, work zones with speed limit of 45 mph and without a flagger, and work zones with speed limit of 55 mph. Each of these models can be adjusted to non-ideal conditions. Methods to estimate the length of moving queue, delay and users’ cost were developed to handle the cases where a demand higher than capacity causes queue. The queue length and delay were estimated for all the data sets using the proposed method. The results also were compared with the QuickZone 2 outputs. When the arrival volume in an interval was less than the capacity of the interval, the QuickZone2 did not yield any delay or queue length even though there was congestion and delay in a part of the interval.Illinois Department of Transportation ICT-10-075 UILU-ENG-2010-2016published or submitted for publicationnot peer reviewe

Field Evaluation of Smart Sensor Vehicle Detectors at Intersections— Volume 2: Performance Under Adverse Weather Conditions

Two microwave-based systems for vehicle detection (by Wavetronix and MS SEDCO) were evaluated at stop bar and advance zones of a signalized intersection under three adverse weather conditions: (1) wind, (2) snow-covered roadway, and (3) rain. Weather effects were very different for the two systems both in terms of the type of condition that could affect performance and in the magnitude of those effects. For Wavetronix, wind had significant effects on the advance zone by increasing false calls to over 50%, but it did not affect the stop bar zones. On the other hand, false calls in snow significantly increased to more than 40% in the stop bar zones and to about 30% in the advance zone. Snow also increased missed and stuck-on calls but in lower proportion than the false calls. Rain also affected the detection at stop bar zones, but all error types were below 8%, and it did not affect the advance zone. For Intersector, weather effects were less pronounced both at the stop bar and advance zones. Snow increased false calls to a range of about 4% to 8% compared to 1.65% to about 4% in normal weather. In addition, rain increased stuck-on calls to a range of 2.7% to 6.35% at the stop bar zones and increased missed calls at advance zones to 3.44%. Wind had no significant effects at stop bar or advance zones. In particular for the rain data, the intensity of the precipitation seemed to be related to the degree of performance degradation. In datasets with higher precipitation per unit of time, higher false calls were observed at Wavetronix stop bar zones, and a higher frequency of missed calls was observed at the Intersector advance zone. Findings from this evaluation can provide valuable information to users and manufacturers of these products regarding expected performance under adverse weather conditions at locations with similar mountings and settings, as well as insight about potential solutions to preventing negative effects in such scenarios.Illinois Department of Transportation R27-95published or submitted for publicationnot peer reviewe

Field Evaluation of Smart Sensor Vehicle Detectors at Intersections – Volume 1: Normal Weather Conditions

Microwave-based vehicle detection products from two manufacturers were selected for field testing and evaluation: Wavetronix and Intersector. The two systems were installed by the manufacturer/distributor at a signalized intersection. Initial evaluation was performed and the results were shared with the companies. They were given an opportunity to change or fine-tune the systems’ setup, if they wanted, resulting in a modified setup. Results are presented in this report in terms four types of errors (false, missed, stuck-on, and dropped calls). At the stop bar, at least 94% of detections for Wavetronix and 96% for Intersector were correct. At stop bar zones, the overall occurrence of false calls for Wavetronix ranged from 0.56% to 1.62%. Missed calls were low for Zones 1 and 2 (0.13% and 0.43%) but significantly higher in Zone 3 (6.05%). Also, stuck-on calls were only observed in Zone 3 (0.58%), and a few dropped calls were found almost exclusively in Zone 3 (0.16%). For Intersector, false calls ranged from 1.4% to 3.56% and missed calls ranged between 0.05% and 0.27%. Stuckon calls ranged from 0.92% for 2.83% and dropped calls were very low (0% and 0.19%). At the advance zones, at least 91% of detections for Wavetronix and 99% for Intersector were correct. For the advance zone, a direct comparison of the two systems was not performed because Wavetronix covered all three lanes combined, but Intersector had one zone covering only the center lane. Wavetronix did not have any stuck-on or dropped calls, missed calls were 1.07%, and false calls were 8.29% for the summer and fall datasets combined. Intersector had no dropped calls, 0.04% stuck-on calls (only one call), 0.8% missed calls, and 0.7% false calls. Additional testing is under way to evaluate the performance of the two systems under inclement weather conditions.Illinois Department of Transportation R27-95published or submitted for publicationnot peer reviewe