This report describes the methodology and results of analyses performed to determine the effectiveness of Ohio Department of Transportation processes for establishing work zone speed zones. Researchers observed motorists' speed choice upstream of and adjacent to various work zone conditions used to justify reduced speed limits in work zones. Researchers also observed speed choice upstream and within variable work zone speed zones. Based on previous research and the results of the studies documented herein, researchers made recommendations regarding appropriate speed limit reductions for shoulder activity, lane shifts, lane closures, and median crossovers. Researchers also recommended the expanded use of variable work zone speed zones.

The Iowa Department of Transportation (DOT) has made improving work zone (WZ) safety a high priority. Managing vehicle speeds through work zones is perceived to be an important factor in achieving this goal. A number of speed reduction techniques are currently used by transportation agencies throughout the country to control speeds and reduce speed variation at work zones. The purpose of this project is to study these and other applicable work zone speed reduction strategies. Furthermore, this research explores transportation agencies' policies regarding managing speeds in long-term, short-term, and moving work zones. This report consists of three chapters. The first chapter, a literature review, examines the current speed reduction practices at work zones and provides a review of the relevant literature. The speed control strategies reviewed in this chapter range from posting regulatory and advisory speed limit signs to using the latest radar technologies to reduce speeds at work zones. The second chapter includes a short write-up for each identified speed control technique. The write-up includes a description, the results of any field tests, the benefits and the costs of the technology or technique. To learn more about other state policies regarding work zone speed reduction and management, the Center for Transportation Research and Education conducted a survey. The survey consists of six multipart questions. The third chapter provides summaries of the response to each question.

Get a complete look into modern traffic engineering solutions Traffic Engineering Handbook, Seventh Edition is a newly revised text that builds upon the reputation as the go-to source of essential traffic engineering solutions that this book has maintained for the past 70 years. The updated content reflects changes in key industry standards, and shines a spotlight on the needs of all users, the design of context-sensitive roadways, and the development of more sustainable transportation solutions. Additionally, this resource features a new organizational structure that promotes a more functionally-driven, multimodal approach to planning, designing, and implementing transportation solutions. A branch of civil engineering, traffic engineering concerns the safe and efficient movement of people and goods along roadways. Traffic flow, road geometry, sidewalks, crosswalks, cycle facilities, shared lane markings, traffic signs, traffic lights, and more—all of these elements must be considered when designing public and private sector transportation solutions. Explore the fundamental concepts of traffic engineering as they relate to operation, design, and management Access updated content that reflects changes in key industry-leading resources, such as the Highway Capacity Manual (HCM), Manual on Uniform Traffic Control Devices (MUTCD), AASSHTO Policy on Geometric Design, Highway Safety Manual (HSM), and Americans with Disabilities Act Understand the current state of the traffic engineering field Leverage revised information that homes in on the key topics most relevant to traffic engineering in today's world, such as context-sensitive roadways and sustainable transportation solutions Traffic Engineering Handbook, Seventh Edition is an essential text for public and private sector transportation practitioners, transportation decision makers, public officials, and even upper-level undergraduate and graduate students who are studying transportation engineering.

The project focuses on two major issues - the improvement of current work zone design practices and an analysis of vehicle interarrival time (IAT) and speed distributions for the development of a digital computer simulation model for queues and travel delays in work zones. Important considerations in the development of work zone design guidelines include guidance, delineation, and the safety of workers and drivers. A nationwide survey of current work zone best practices was conducted. Based on the review of the existing ODOT guidelines, superior practices available in other states, relevant research, and professional judgment of personnel involved in work zone activities, a set of guidelines for work zone design are proposed. It is anticipated that these research findings will result in the better design of work zones which will minimize traffic delays and improve safety. In the second part of the project trailers, each using two Wavetronix microwave radar units in side-fire mode, were developed to nonintrusively measure traffic. The traffic was measured at six work zones sites with different types of lane configurations at different freeways in Ohio. Traffic on the road was also independently measured using video and radar, and the results compared to records from the trailers to verify that the trailers were measuring the traffic with reasonable accuracy. IAT data of successive vehicles in freeflowing traffic ahead of work zones were analyzed and IAT distributions were generated as a function of the traffic volume for each lane and relationships between traffic volumes and cumulative IAT distributions were established allowing a direct conversion from hourly traffic counts to corresponding cumulative IAT distributions. This conversion method produces fairly accurate cumulative IAT distributions for selected hourly traffic volumes. It was also found that the same cumulative IAT distribution can be used to model the free-flowing traffic at other freeway locations in Ohio, which means that the IAT distributions are portable and scalable and a microscopic digital computer simulation model based on queueing theory may be developed to investigate traffic delays in work zones.

This synthesis documents information regarding the current state of practice for work zone speed management. The report compiles data, procedures, techniques, and technical issues related to observing and comparing work zone speeds. The speed management measures have been organized into four categories: engineering, operational, enforcement, and public education and outreach. Information included in this study was acquired through a review of the literature, two surveys of state department of transportation representatives in all states, a compilation of state agency public information campaigns, and follow-up interviews with select survey respondents from several U.S. states and one Canadian province.

Safety hazards are increased in highway work zones as the dynamics of a work zone introduce a constantly changing environment with varying levels of risk. Excessive speeding through work and maintenance zones is a common occurrence which elevates the dangers to both drivers and motorists in the work zone. Although most work zones are controlled by reduced speed limits or state law enforcement, driver adherence to these regulations and laws in very minimal, especially in work zones. Several studies have shown a correlation between speeding in work zones and traffic crashes which lead most traffic safety professionals to conclude that excessive speeding and speed variance are the contributing factors in a large percentage of traffic crashes, injuries or fatalities. The most influential factor in achieving speed compliance in the work zone is the driver's perception of heightened risk. The main objective of this study was to determine the safest and most effective countermeasure for the reduction of vehicular speeds within construction and maintenance work zones. The purpose of the simulator experiment was to determine the effectiveness of 20 countermeasures on the reduction of speed through work zones in a controlled laboratory setting. The literature review identified several past research studies utilizing speed reduction countermeasures in work zones and under normal traffic conditions. From this review, 20 countermeasures were selected for evaluation based upon discussions with ODOT personnel.The post hoc tests indicated that the presence of construction workers, presence of construction vehicles, law enforcement, speed photo enforcement and shifting lanes were most effective at reducing speeds in work zones. The least effective speed reduction countermeasures included 3 sets of 3 rumble strips, concrete barriers, other channelizing devices and changeable message signs with speed reductions less than 10 mph.

The construction zone speed limit sign used in Illinois consists of a regulatory 45 mph speed limit sign augmented with two small strobe lights and two orange colored plates. When the lights are flashing the speed limit is 45 mph. This report contains the findings from evaluation of the effectiveness of the flashing lights in reducing speeds in a rural interstate construction zone. The speed reduction effects on cars and trucks were determined at two locations within the work zone. The results indicated that the average speed of cars was reduced by 1.9-7.1 mph and that of trucks by 1.3-6.0 mph when the strobe lights were flashing. In general, the speed reduction effects were more pronounced on the cars than on the trucks, and at a location past the work space than before it. The reductions at the location past the work space were 2-3 times more than the reductions at the location before the work space. Cars reduced their speeds, on the average, by 1.9 to 4.9 mph before and by 5.9 to 7.1 mph after the work space. Similarly, the speed reduction for trucks was 1.3-2.9 mph before and 3.3-6.0 after the work space. In general, the percentages of vehicles with excessive speeds in the work zone decreased when the lights were flashing.