scholarly journals Effect of Work Zone Lighting on Drivers’ Visual Performance and Perceptions of Glare

Author(s):  
Rajaram Bhagavathula ◽  
Ronald B. Gibbons

Nighttime crashes at work zones are major concerns for construction workers and motorists. Although in a majority of the U.S. states, department of transportation specifications for work zone lighting mention that contractors should reduce glare for workers and drivers, only two states advocate detailed specifications like light positions, orientation, and light levels. Although some studies have examined the impact of glare from work zone lights on workers and others have calculated veiling luminance levels for drivers in the work zone, the effect of work zone lighting on drivers’ visual performance and glare perception has never been studied in a realistic setting. The goal of this study was to understand the impact of commercially available portable light towers (metal halide, LED, and balloon) and their orientation on drivers’ visual performance and their perceptions of glare. Participants drove through a realistic work zone simulated on the Virginia Smart Road. Visual performance was assessed by a detection task and perception of visibility and glare were assessed by questionnaires. Results indicated that the type of light tower and its orientation affect visual performance and perceptions of visibility and glare. Light towers aimed toward the driver resulted in lowering drivers’ visual performance, both objectively and subjectively. When the light towers were aimed away from or perpendicular to the driver, the visual performance was higher and the differences in visual performance between the types of light towers were minimal. These findings indicate that these orientations should be preferred for work zone light towers.

Author(s):  
Roger P. Bligh ◽  
King K. Mak ◽  
Lewis R. Rhodes

Proper traffic control and delineation are critical to achieving safety in work zones. However, the work zone traffic control devices themselves may pose a safety hazard to vehicle occupants or work crews when impacted by errant vehicles. Thus, there was a need to research the safety performance of work zone traffic control devices to ensure that they perform satisfactorily and meet NCHRP Report 350 guidelines. Several research studies sponsored by the Texas Department of Transportation evaluated the impact performance of various work zone traffic control devices, such as temporary and portable sign supports, plastic drums, sign substrates for use with plastic drums, traffic cones, and vertical panels. Specifically addressed are the studies on barricades. Standard wooden barricade construction was found to be unacceptable due to a demonstrated potential for intrusion of fractured members into the occupant compartment. In response to deficiencies identified in the wooden barricade tests, several alternate barricade designs were developed and successfully tested.


Author(s):  
Michelle M. Mekker ◽  
Yun-Jou Lin ◽  
Magdy K. I. Elbahnasawy ◽  
Tamer S. A. Shamseldin ◽  
Howell Li ◽  
...  

Extensive literature exists regarding recommendations for lane widths, merging tapers, and work zone geometry to provide safe and efficient traffic operations. However, it is often infeasible or unsafe for inspectors to check these geometric features in a freeway work zone. This paper discusses the integration of LiDAR (Light Detection And Ranging)-generated geometric data with connected vehicle speed data to evaluate the impact of work zone geometry on traffic operations. Connected vehicle speed data can be used at both a system-wide (statewide) or segment-level view to identify periods of congestion and queueing. Examples of regional trends, localized incidents, and recurring bottlenecks are shown in the data in this paper. A LiDAR-mounted vehicle was deployed to a variety of work zones where recurring bottlenecks were identified to collect geometric data. In total, 350 directional miles were covered, resulting in approximately 360 GB of data. Two case studies, where geometric anomalies were identified, are discussed in this paper: a short segment with a narrow lane width of 10–10.5 feet and a merging taper that was about 200 feet shorter than recommended by the Manual on Uniform Traffic Control Devices. In both case studies, these work zone features did not conform to project specifications but were difficult to assess safely by an inspector in the field because of the high volume of traffic. The paper concludes by recommending the use of connected vehicle data to systematically identify work zones with recurring congestion and the use of LiDAR to assess work zone geometrics.


Author(s):  
Mohsen Kamyab ◽  
Stephen Remias ◽  
Erfan Najmi ◽  
Kerrick Hood ◽  
Mustafa Al-Akshar ◽  
...  

According to the Federal Highway Administration (FHWA), US work zones on freeways account for nearly 24% of nonrecurring freeway delays and 10% of overall congestion. Historically, there have been limited scalable datasets to investigate the specific causes of congestion due to work zones or to improve work zone planning processes to characterize the impact of work zone congestion. In recent years, third-party data vendors have provided scalable speed data from Global Positioning System (GPS) devices and cell phones which can be used to characterize mobility on all roadways. Each work zone has unique characteristics and varying mobility impacts which are predicted during the planning and design phases, but can realistically be quite different from what is ultimately experienced by the traveling public. This paper uses these datasets to introduce a scalable Work Zone Mobility Audit (WZMA) template. Additionally, the paper uses metrics developed for individual work zones to characterize the impact of more than 250 work zones varying in length and duration from Southeast Michigan. The authors make recommendations to work zone engineers on useful data to collect for improving the WZMA. As more systematic work zone data are collected, improved analytical assessment techniques, such as machine learning processes, can be used to identify the factors that will predict future work zone impacts. The paper concludes by demonstrating two machine learning algorithms, Random Forest and XGBoost, which show historical speed variation is a critical component when predicting the mobility impact of work zones.


Author(s):  
Nipjyoti Bharadwaj ◽  
Praveen Edara ◽  
Carlos Sun

Identification of crash risk factors and enhancing safety at work zones is a major priority for transportation agencies. There is a critical need for collecting comprehensive data related to work zone safety. The naturalistic driving study (NDS) data offers a rare opportunity for a first-hand view of crashes and near-crashes (CNC) that occur in and around work zones. NDS includes information related to driver behavior and various non-driving related tasks performed while driving. Thus, the impact of driver behavior on crash risk along with infrastructure and traffic variables can be assessed. This study: (1) investigated risk factors associated with safety critical events occurring in a work zone; (2) developed a binary logistic regression model to estimate crash risk in work zones; and (3) quantified risk for different factors using matched case-control design and odds ratios (OR). The predictive ability of the model was evaluated by developing receiver operating characteristic curves for training and validation datasets. The results indicate that performing a non-driving related secondary task for more than 6 seconds increases the CNC risk by 5.46 times. Driver inattention was found to be the most critical behavioral factor contributing to CNC risk with an odds ratio of 29.06. In addition, traffic conditions corresponding to Level of Service (LOS) D exhibited the highest level of CNC risk in work zones. This study represents one of the first efforts to closely examine work zone events in the Transportation Research Board’s second Strategic Highway Research Program (SHRP 2) NDS data to better understand factors contributing to increased crash risk in work zones.


Author(s):  
John D. Bullough ◽  
Ute C. Besenecker ◽  
Jeremy D. Snyder ◽  
Nicholas P. Skinner

In part because of the potential for high levels of glare from work zone illumination, recommendations for light levels from work zone illumination systems are substantially higher than for levels used along roadways in non–work zone locations. In a two-part study, requirements for work zone illumination light levels were assessed. First, levels for workers varying in age from 20 to 60 years were evaluated with the relative visual performance model, with and without the presence of visibility-reducing glare. Except for the smallest, lowest-contrast tasks performed by the older workers, an illuminance of 10 lx resulted in visibility well above the threshold even in the presence of glare, and an illuminance of 30 lx resulted in suprathreshold visibility for these conditions as well. The results of these computational analyses were largely confirmed in a full-scale, outdoor field demonstration attended by transportation agency engineers and highway contractors. Together, the findings suggest that when lighting systems provide sufficient glare control, light levels do not always need to be especially high to ensure adequate visibility for workers.


Author(s):  
Bekir Bartin ◽  
Kaan Ozbay ◽  
Matthew D. Maggio ◽  
Hao Wang

Faced with a growing number of work zones, transportation agencies are being challenged to effectively manage the impacts of these zones, alleviate congestion, and maintain the safety of motorists and workers without disrupting project schedules. Coordinating work zones has already been practiced by various state departments of transportation and transportation agencies, yet there are no universal department of transportation policies that address how agencies should coordinate or consolidate projects. In addition, only a few states utilize computer tools specific to regional or corridor-based work zone coordination. State departments of transportation mostly coordinate significant and long-term projects. However, the majority of roadway projects include minor repair, roadway maintenance, bridge maintenance, surveying, and landscape and utility work that require relatively short-term work zones. The Work Zone Coordination Software tool was developed to provide the New Jersey Department of Transportation with an easy-to-use tool to evaluate the feasibility and effectiveness of coordinating short- and long-term work zones and to measure the benefits. This online tool is implemented with a web-based user interface. It integrates all scheduled and active construction projects, identifies conflicts between work zone projects, and estimates the benefits of conflict mitigation. The Work Zone Coordination Software tool works with the New Jersey work zone database by automatically importing data to provide up-to-date information to its users. However, the tool is built on a flexible framework that allows the integration of any work zone database provided that it includes all the required information.


Author(s):  
King K. Mak ◽  
Roger P. Bligh ◽  
Lewis R. Rhodes

Safety of work zones is a major area of concern since it is not always possible to maintain a level of safety comparable to that of a normal highway not under construction. Proper traffic control is critical to the safety of work zones. However, traffic control devices themselves may pose a safety hazard when impacted by errant vehicles. The impact performance of many work zone traffic control devices is mostly unknown, and little, if any, crash testing has been conducted in accordance with guidelines set forth in NCHRP Report 350. The Texas Department of Transportation (TxDOT) has, in recent years, sponsored a number of studies at the Texas Transportation Institute to assess the impact performance of various work zone traffic control devices, including plastic drums and sign substrates, temporary and portable sign supports, plastic cones, vertical panels, and barricades. The results, findings, conclusions, and recommendations are presented for temporary and portable sign supports, plastic drums, sign substrates for use with plastic drums, traffic cones, and vertical panels, whereas those for barricades are covered elsewhere. Most of the work zone traffic control devices satisfactorily met the evaluation criteria set forth in NCHRP Report 350 and are recommended for field implementation. However, some of the devices failed to perform satisfactorily and are not recommended for field applications. The results from these studies are being incorporated into the TxDOT barricade and construction standard sheets for use in work zones.


2018 ◽  
Author(s):  
◽  
Yohan Chang

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] This dissertation research focuses on modeling traffic conditions affected by disruptive events such as work zones, incidents, and hurricanes. Using a combination of field data and simulation experiments, this research tried to address the relationship between disruptive events and their impact on traffic conditions and driver behavior. The first half of the dissertation assesses the impact of work zones. First, a data-driven assessment of the traffic impact of work zones using different data sources was conducted. A tool was developed for practitioners to estimate the delay and travel times of planned work zones. Second, traffic flow and speed prediction models were developed for work zones in order to assist with the better scheduling of work activity. Machine learning approaches were used to develop the prediction models. In addition to work zone effects, the effects of another special event, baseball gameday conditions, were also studied and traffic prediction models were developed. Third, using naturalistic driving study data, classification algorithms categorized work zone events into crashes, nearcrashes, and baseline conditions. In the second half of the dissertation, the focus shifts to the effect of emergency on evacuation. Two chapters in this section present the results of different traffic management strategies -- 1) contraflow crossover and ramp closure optimization and 2) reservation-based intersection control in connected and autonomous vehicle environment.


2017 ◽  
Vol 2645 (1) ◽  
pp. 184-194 ◽  
Author(s):  
Junseo Bae ◽  
Kunhee Choi ◽  
Jeong Ho Oh

Impact assessments of highway construction work zones (CWZs) are mandated for all federally funded highway infrastructure improvement projects. However, most existing approaches are ad hoc or project specific, so they are incapable of being benchmarked for any particular spatial region. A novel multicontextual approach to modeling the traffic impact of urban highway CWZs is proposed and tested in this paper. The proposed approach is unique because it models the impact of CWZ operations through a multicontextual quantitative method using big data for improved accuracy. In this study, a machine-learning technique was adopted to predict long-term traffic flow rates and the corresponding truck percentages. With the use of these predicted values, stereotypical patterns of traffic volume-to-capacity ratios were created for typical urban nighttime closures. Third-order curve-fitting models to achieve potential work zone travel time delays in heavily trafficked large urban cores were then developed and validated. This study will greatly help state and local governments and the general traveling public in major cities know the potential traffic flow resulting from construction and thereby facilitate progress on highway improvement projects with the better-informed work zone traffic flow and thus improve safety and mobility in and between CWZs.


2018 ◽  
Vol 29 (2) ◽  
pp. 19-36
Author(s):  
Nawaf M. Alshabibi Nawaf M. Alshabibi

This paper assesses the impact of long-term work zones in arterial roads on commercial activities in Dammam Metropolitan area. The study focuses on two cases of long-term work zones in arterials in two major cities in Dammam Metropolitan Area. The first case is a work zone with full lanes closure on Prince Mohamed Bin Fahad Road at the south east entrance of Dammam city. The second case is a work zone with full lanes closure on King Abdul-Aziz Road at the northern entrance of Al-Khobar City. Data collection relies on field survey including questionnaires to affected business owners and managers. The questionnaire has been developed to assess the impact before and during road works period, in the work zone, on mobility and accessibility to commercial activities. Field survey includes 201 commercial activities at two work zone locations. Answers have been registered in Excel spreadsheet. Data analysis includes percentages of change, means, and standard deviation of dependent variables before and during the presence of the work zone. It was found that long-term work zones on arterials have multiple negative impacts on workers, sales, and customers. These impacts are related to lack of mobility, accessibility and reduction of parking availability during work period. Also, restaurants and travel agencies were the most effected activities by work zone presence, while banks were the least effected.


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