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.
As traffic-related work zone crashes continue to increase across the nation, safety of road users and workers has become a top priority for transportation agencies. Since inattention and irresponsible behavior by drivers are surmised to contribute to the frequency of work zone crashes, a program featuring extraordinary presence of and enforcement by law officers has been implemented in many states to address this concern. A literature search of such programs and related research was conducted. While the overall benefits of these activities have been found positive, much of the evidence has been anecdotal. To assess the scope of extra work zone enforcement programs, a survey was developed and distributed to state departments of transportation across the nation. This survey sought information regarding these efforts such as criteria for selection of target work zones, methods of enforcement operations, and beneficial results. A special survey was also designed and distributed to enforcement agencies in Iowa and other selected states. In addition to the surveys, personal contacts and office visits were conducted by the research team staff. The study found that use of extra enforcement in work zones is a common practice in many states and these activities appear to be increasing. Current literature, survey responses, and interviews have all indicated a prevalent opinion for the benefits of increased law enforcement presence and activity in work zones. Very few comments offered conclusions of negative impacts, such as additional congestion, from these efforts. However, the beneficial effects of focused enforcement have not been intensively quantified. In addition, procedures for the use of law officers in work zones are quite inconsistent across the nation, as is the general implementation of specific legislation addressing work zone traffic violations. Similar variation can be found in funding levels and sources for enforcement activities in work zones among the states. Training of law officers prior to work zone duty does not appear to be commonly required, though the value of focused training is being recognized in some states. As crashes and deaths continue to rise annually in our nation's work zones, it is imperative that demonstrated beneficial programs such as the expanded use of law officers in these locations be continued, refined, and expanded. Future study is needed to supplement the knowledge base and provide guidance to agencies when considering the use of law enforcement to calm traffic, ensure compliance with traffic laws, and thus provide for safer work zones.
Statistics from the South Carolina Department of Transportation (SCDOT) for incidents between 1998 and 2002 reveal that a leading cause of crashes in work zones is driving too fast for conditions. In April 2005, a team of researchers led by Clemson University Transportation Systems Laboratory embarked on research to better manage speed control in work zones. The research tasks included field trials of several devices, a literature review, and a survey of states. Based on the literature review and meetings with the project steering committee, a number of devices and strategies were selected for field evaluation. The selected devices included drone radar, changeable message sign with radar (CMR), a speed monitoring display (SMD) with CMS, portable rumble strips, and a novel speed activated sign designed by the researchers. Each of the devices had to be acquired and/or developed for this project and preliminary testing was conducted to identify an acceptable configuration for actual data collection. After the initial testing, field surveillance of the speed management devices at a variety of different work zone sites on interstates and state route highways in South Carolina was completed to collect the empirical data needed for evaluation. Both quantitative and qualitative analyses of the performance of the devices and strategies were completed. Some of the devices were also studied in combination with police enforcement. The results of the analysis show that all of the speed control devices studied during this project has the capability of lowering speeds. This report summarizes the findings of this research and provides several recommendations in choosing a speed control device for a particular work zone application.
Human Factors and Ergonomics have made a considerable contribution to the research, design, development, operation and analysis of transportation systems which includes road and rail vehicles and their complementary infrastructure, aviation and maritime transportation. This book presents recent advances in the Human Factors aspects of Transportation. These advances include accident analysis, automation of vehicles, comfort, distraction of drivers (understanding of distraction and how to avoid it), environmental concerns, in-vehicle systems design, intelligent transport systems, methodological developments, new systems and technology, observational and case studies, safety, situation awareness, skill development and training, warnings and workload. This book brings together the most recent human factors work in the transportation domain, including empirical research, human performance and other types of modeling, analysis, and development. The issues facing engineers, scientists, and other practitioners of human factors in transportation research are becoming more challenging and more critical. The common theme across these sections is that they deal with the intersection of the human and the system. Moreover, many of the chapter topics cross section boundaries, for instance by focusing on function allocation in NextGen or on the safety benefits of a tower controller tool. This is in keeping with the systemic nature of the problems facing human factors experts in rail and road, aviation and maritime research– it is becoming increasingly important to view problems not as isolated issues that can be extracted from the system environment, but as embedded issues that can only be understood as a part of an overall system.
