ICT/IDOT Improve Safety and Mobility in Work Zones

Rolling operation in the work zone lane with flagger controlling speed in the live lane.

Flaggers are a common sight in work zones on Illinois roadways, including expressways and freeways. Flaggers control and direct drivers traveling through work zones. While not formally used in Illinois work zones, spotters typically monitor traffic and warn workers of errant drivers or other hazards.

A critical question is how to minimize risks to workers in work zones and to the traveling public. Other important issues are finding ways to use flaggers and spotters more effectively in maintaining work zone safety and mobility and to identify additional methods to manage and direct traffic through a work zone.

These are concerns that the Illinois Department of Transportation (IDOT) and the Illinois State Toll Highway Authority wanted to address as part of a larger effort to improve worker and road user safety on Illinois roadways.

To meet that objective, IDOT sponsored a study, “Effect of Flaggers and Spotters in Directing Work Zone Traffic for Illinois Freeways and Expressways” (R27-109). ICT researchers investigated the latest standards and research on the use of flaggers and spotters in multilane work zones with a posted speed limit great than 40 mph, performed site visits and field studies to evaluate current practices, analyzed data and reports on work zone crashes in Illinois from 1996 through 2009, and conducted a survey of resident engineers and construction personnel in IDOT and other state departments of transportation.

The study was facilitated by a technical review panel (TRP) co-chaired by Paul Lorton, Safety Programs Unit Chief of IDOT’s Bureau of Safety Engineering, and John Benda, General Manager of Maintenance and Traffic for the Illinois Tollway. Investigators for the study were Professor Khaled El-Rayes, Associate Professor Liang Liu, and Assistant Professor Nora El-Gohary, from the Department of Civil and Environmental Engineering at the University of Illinois at Urbana-Champaign.

The outcome of the study was a set of recommendations on the use of flaggers, spotters, and other safety measures in work zones with a speed limit greater than 40 mph on Illinois expressways and freeways, including the following:

  • Minimize the exposure of flaggers and spotters to traffic hazards by positioning them in locations away from traffic when they are not directing traffic through a work zone, establish a predetermined escape route for each flagger and spotter, and limit their tasks to monitoring traffic from a safe location and guiding traffic only when needed.
  • Supplement the use of spotters with temporary traffic control devices such as police patrols, a work vehicle with a warning beacon, portable speed-monitoring displays, and portable changeable message signs.
  • Provide additional training to flaggers and spotters.
  • Update IDOT standards, specifications, and requirements to implement these recommendations.

El-Rayes says that the study’s findings are intended to guide decision makers in changing or expanding existing policies to improve work zone safety and mobility performance on future road and bridge construction projects.

TRP co-chair Paul Lorton underscores the importance of the project and its recommendations: “Work zone safety is critical for road users and workers on all Illinois roadways. Identification of additional steps that may be considered to enhance work zone safety—particularly on the higher-speed expressways and freeways—is one positive step toward IDOT’s goal of making zero fatalities a reality.”

A copy of the full report is available on ICT’s website.

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