The driving conditions of work zones differ from normal driving conditions. In addition, the driving conditions of each type of work zone (short-term, long-term, etc.) may differ from those of another type of work zone. These factors can result in violations of road user expectancy, which in turn can lead to congestion, erratic maneuvers, and ultimately crashes. Lack of driver knowledge of appropriate work zone driving actions, failure to obey traffic laws, and lack of awareness of work zones and/or workers also detract form work zone safety. As more and more of the nation?s infrastructure reaches the end of its life cycle and fewer new roadways are constructed, work zones are becoming more and more prevalent on our roadways. This increased exposure to work zones increases opportunities for crashes to occur. Strategies that address all of these issues are presented and discussed in Section V.
One of the hallmarks of the AASHTO Strategic Highway Safety Plan (SHSP) is to approach safety problems in a comprehensive manner. The range of strategies available in the guides will ultimately cover various aspects of the road user, the highway, the vehicle, the environment, and the management system. The guides strongly encourage the user to develop a program to tackle a particular emphasis area from each of these perspectives in a coordinated manner. To facilitate this coordination, the electronic form of the material uses hypertext linkages to enable seamless integration of various approaches to a given problem. As more guides are developed for other emphasis areas, the extent and usefulness of this form of implementation will become ever more apparent.
The goal of the SHSP is to move away from independent activities of engineers, law enforcement, educators, judges, and other highway-safety specialists and toward the coordinated formation of working groups and alliances that represent all of the elements of the safety system. In so doing, people can draw upon their combined expertise to reach the bottom-line goal of targeted reduction of crashes and fatalities associated with a particular emphasis area.
The six major areas of the AASHTO SHSP (Drivers, Vehicles, Special Users, Highways, Emergency Medical Services, and Management) are subdivided into 22 goals, or key emphasis areas, that impact highway safety. One of these goals addresses the improvement of safety in work zones. This implementation guide provides guidance to highway agencies that desire to implement safety improvements in work zones. It includes a variety of strategies that may be applicable to specific work zones or to agency procedures.
General Description of the Problem
In 2003, there were 919 fatal crashes (1,028 fatalities) and more than 40,000 persons injured in work zone crashes on America?s highways (Fatal Accident Reporting System, or FARS, January 2005). Exhibit I-1 displays a trend of increasing deaths attributed to work zones from 1994 to 2003. During this timeframe, anecdotal evidence suggests that the number of work zones have increased, although no definitive evidence or study encompasses all types of work zones. As more and more of the nation?s infrastructure reaches the end of its life cycle, work zones are expected to remain a familiar sight on our roadways.
Number of Work Zone Fatal Crashes and Fatalities, 1994?2003
Exhibit I-2 shows the types of work zones in which fatal crashes occurred in 2003. The preponderance of crashes occurred in long-term construction zones. Issues faced may vary by type of work zone, but safety improvements for all types of work zones are considered in the strategies discussed in Section V.
A review of FARS data for 2003 yields additional insights into fatal crash characteristics in work zones:
- More than half of all fatal work zone crashes occurred during the day.
- More than twice as many work zone fatal crashes occurred on weekdays as on weekends.
- Fatal work zone crashes occurred most often during the summer months.
- Almost 30 percent of fatal work zone crashes occurred on Interstate roadways.
- Almost 60 percent of fatal work zone crashes occurred on roads with a posted speed limit of 55 mph or greater.
- Single-vehicle crashes accounted for over half of all fatal work zone crashes.
- Rear-end fatal crashes were 25 times more common in work zones relative to all fatal crashes.
- Ten percent of work zone fatalities were pedestrians and bicyclists.
- Heavy trucks were involved in more than 20 percent of fatal work zone crashes.
- Alcohol was involved in almost 40 percent of fatal work zone crashes.
Work Zone Fatal Crashes by Work Zone Type in 2003
In addition to the trends identified in FARS, an American Road and Transportation Builders Association (ARTBA) review of federal data from the Bureau of Labor Statistics indicates that roadway construction workers are killed at a rate nearly three times higher than other construction workers and eight times higher than general industry workers.
Objectives of the Emphasis Area
The work zone safety experiences described above are the basis for the inclusion of the strategies discussed in Section V. The strategies are grouped by objective (i.e., safety concern). The objectives for improving work zone safety are explained below. Exhibit I-3 lists the objectives and the related strategies discussed in this guide. The strategies span the full range of engineering, enforcement, and education:
- 19.1 A Reduce the number, duration, and impact of work zones—Reducing the exposure of travelers to work zones and of workers to traffic will decrease the opportunities for crashes to occur. This exposure can be reduced by using maintenance and construction practices that increase pavement and bridge service life, accelerating construction and maintenance activities when they are needed, scheduling highway work to avoid periods of high traffic volumes, and providing adequate space for future road work in new project development.
- 19.1 B Improve work zone traffic control devices—Since work zones often present a higher driver-information and vehicular-control workload than nonwork areas present, the devices used to convey information to drivers and to alert them to the presence of workers and potential roadway hazards need to be visible and to have a clear and consistent meaning. Visibility of workers (especially flaggers) and their vehicles are necessary for the protection of both workers and highway users.
- 19.1 C Improve work zone design practices—Addressing safety for highway users and workers in the planning stages of a project can reduce the potential for crashes related to the work zone. Establishing work zone design guidance, including providing consistent design features across a jurisdiction, provides highway users with an environment that better meets their expectations. Positive separation between the traffic space and the work space can help reduce potential for conflicts between road users and/or workers. Consideration of all road users in the design of work zones can help improve safety for all users by providing cues to and accommodation of both motorized vehicles and nonmotorized travelers.
- 19.1 D Improve driver compliance with work zone traffic controls—Many crashes are caused or aggravated by drivers? noncompliance with traffic control devices or traffic laws in work zones. Enforcement campaigns (conventional or automated) have the potential to reduce undesirable driver behavior and improve safety in work zones. Signs that convey credible messages regarding speed limits or presence of workers contribute to driver compliance with traffic laws.
- 19.1 E Increase knowledge and awareness of work zones—Training of highway users, designers, and workers can improve how work zones are designed, set up, and used. Public information and education campaigns can help improve driver skills in guiding vehicles through work zones. Training programs for agency staff and workers can help ensure that traffic control devices designed and set up in work zones are appropriate and provide positive guidance, rather than create additional clutter and driver confusion.
- 19.1 F Develop procedures to effectively manage work zones—Work zone management practices, such as crash data system improvements, safety awards, interagency coordination, and inspections, can help bring about an improvement in work zone safety at an agency level.
Emphasis Area Objectives and Strategies
|19.1 A Reduce the number, duration, and impact of work zones
||19.1 A1 Improve maintenance and construction practices (P)
|19.1 A2 Utilize full-time roadway closure for construction operations (T)
|19.1 A3 Utilize time-related contract provisions (P)
|19.1 A4 Use nighttime road work (P)
|19.1 A5 Use demand management programs to reduce volumes through work zones (P)
|19.1 A6 Design future work zone capacity into new or reconstructed highways (T)
|19.1 B Improve work zone traffic control devices
||19.1 B1 Implement ITS strategies to improve safety (E)
|19.1 B2 Improve visibility of work zone traffic control devices (T)
|19.1 B3 Improve visibility of work zone personnel and vehicles (varies)
|19.1 B4 Reduce flaggers? exposure to traffic (T)
|19.1 C Improve work zone design practices
||19.1 C1 Establish work zone design guidance (T)
|19.1 C2 Implement measures to reduce work space intrusions (and limit consequences of intrusions) (T)
|19.1 C3 Improve work zone safety for pedestrians, bicyclists, motorcyclists, and heavy-truck drivers (T)
|19.1 D Improve driver compliance with work zone traffic controls
||19.1 D1 Enhance enforcement of traffic laws in work zones (T)
|19.1 D2 Improve credibility of signs (E)
|19.1 D3 Improve application of increased driver penalties in work zones (T)
|19.1 E Increase knowledge and awareness of work zones
||19.1 E1 Disseminate work zone safety information to road users (T)
|19.1 E2 Provide work zone training programs and manuals for designers and field staff (T)
|19.1 F Develop procedures to effectively manage work zones
||19.1 F1 Develop or enhance agency-level work zone crash data systems (T)
|19.1 F2 Improve coordination, planning, and scheduling of work activities (T)
|19.1 F3 Use incentives to create and operate safer work zones (T)
|19.1 F4 Implement work zone quality assurance procedures (i.e., safety inspections or audits) (T)
(P) = proven; (T) = tried; and (E) = experimental. A detailed explanation of (P), (T), and (E) appears in Section V. Several strategies have substrategies with different ratings.