Zone of safety

May 13, 2015

Safety audits of temporary work zones can yield benefits like audits of permanent roadways

In the 10-year period from 2001 to 2010, more than 9,000 motorists and roadway workers were killed in motor vehicle traffic crashes in work zones. The nature of highway work zones increases the opportunities for drivers to make mistakes.

Much is being done to reduce this number by highway agencies and their industry partners, as attested by a significant reduction in the annual number of work-zone fatalities. There were 576 fatalities in motor vehicle traffic crashes reported in work zones in 2010. This is a 13.6% reduction from 2009 and continues the trend of decreasing work-zone fatalities that has been occurring since work-zone fatalities peaked at 1,186 in 2002.

As work-zone practitioners work to continue this fatality-reduction trend, they are looking to other transportation-safety areas for tools and strategies to improve safety in construction, maintenance and utility work zones. The practice of road-safety audits (RSAs) has been established as a proactive approach to identifying safety issues and recommending treatments on traditional (nonwork-zone) roadways. It involves a third-party team of multidisciplinary experts who bring their individual experiences and expertise to focus on improving safety at a single location or series of work zones. Agencies that have implemented RSAs have recognized the following benefits:

• Reconstruction costs to correct safety deficiencies identified once roads are in service are substantially reduced or avoided;

• Life-cycle costs are reduced, since safer designs often carry lower maintenance costs;

• Societal costs of collisions are reduced by safer roads and a reduction in the number and severity of crashes; and

• Liability claims can be mitigated.

The concept of performing a work-zone RSA is similar to a traditional RSA; a team with varied backgrounds and levels of knowledge can take an active approach to solving temporary traffic-control safety issues during various phases of a project’s life, including during design or an active work zone.

Design stage

A unique set of benefits can be recognized when applying RSAs to work zones at the design stage. Temporary traffic-control (TTC) devices and construction or work-zone staging often represent a large percentage of project costs. Changes to TTC and staging made during the active work-zone phase are often unanticipated and can have significant benefits to overall project costs. By identifying improvements to work-zone elements and staging earlier in the process, substantial savings may be realized.

Active work-zone stage

Recommendations from a work-zone RSA have the potential to affect roadway users immediately and on a large scale when used on active work zones. Work-zone RSAs make it possible to improve travel times, give enhanced notification in advance of road work and improve visibility and conspicuity of TTC devices, in addition to other improvements.

Differentiating from a typical work-zone inspection

In many cases, highway agencies are already performing work-zone inspections to ensure compliance with a set of predetermined policies, nationally recognized standards and the project-specific design plans. These are defined as nominal safety elements. A work-zone RSA, in contrast, is designed to focus on substantive safety: How does (or will) this work zone perform with regard to keeping road users and workers safe? A work-zone RSA can provide a comprehensive overview of all aspects of the work zone and how they work together to affect safety.

There are a number of procedural differences, as well, when comparing work-zone RSAs with typical inspections:

• While work-zone compliance inspections are performed by a limited number of inspectors who are intimately familiar with the project, work-zone RSAs are performed by a multidisciplinary team independent of the project. Team members can include transportation engineers, construction inspectors, law enforcement, first responders and others with various backgrounds;

• Due to their small time commitment, work-zone inspections can be performed on a daily or weekly basis, but work-zone RSAs are to be conducted once per site and project phase; and

• Traditional work-zone inspectors follow a checklist focused on complying with standards, with results displayed as a score or rating. A work-zone RSA will provide identification of potential safety risks, recommended treatments and a call to action in a final report.

Eight-step plan

Conducting a work-zone RSA follows an established eight-step process developed by the Federal Highway Administration (FHWA) for all RSAs.

1. Identify project and phase for RSA

Work-zone RSAs can lead to the selection of more effective traffic-control strategies during the planning and design phases. Work-zone RSAs also can recommend safety treatments during an active work zone, providing opportunity for immediate safety benefit. Work-zone RSAs are applicable to any work zone, and they are particularly recommended when a work zone has a complex traffic-control plan, multiple construction stages, high-profile elements or if the work zone has demonstrated safety issues.

2. Select the work-zone RSA team

It is important to assemble a third-party, multidisciplinary RSA team. Each member should have deep subject-matter expertise and real-world experience in roadway safety, work zones or another applicable topic. Building a team that spans many disciplines promotes outside-the-box solutions. Typical work-zone RSA teams include work-zone engineers, construction inspectors, designers, planners, law enforcement, first responders, local agency staff and human-factors experts.

3. Conduct startup meeting

The purpose of the startup meeting is to introduce the RSA team to the road owner and to introduce the project to the RSA team. The RSA team leader will described the RSA process and individual roles. The road owner will communicate necessary information about the project. Examples may include project length and duration, traffic volumes, any current issues in an active work zone, constraints and limitations for a future project’s temporary traffic-control plan.

4. Perform field (or plan) review

The work-zone RSA team will review the work zone in the field (or the temporary traffic-control plan and transportation-management plan, if at the design or planning stage). For all reviews, it is important to identify the types of road users (e.g., motorists, pedestrians and bicyclists), road-user behavior through the work zone and the basic setup of the work-zone traffic control. For reviews at any phase, a prompt list provides structure for the audit by reminding team members what to look for and ensuring no important aspects are overlooked.

5. Conduct RSA analysis and develop a report on findings

During the review, team members may identify safety concerns. Once they meet as a group to discuss what they learned in the field (or while reviewing plans), the group works to prioritize the safety needs and develop suggestions for reducing the degree of risk. This step may include reviewing safety, operational and geometric data. Recommended solutions are typically identified by range (e.g., short term and lower cost, long term and higher cost). The team will document their findings and recommendations in a draft report to be presented to the road owner.

6. Present findings to road owner

The work-zone RSA team will discuss the identified safety concerns and recommended treatments to the road owner and assist the road owner in making the best choices to improve safety in the current or future work zone. This step also includes a final report submitted by the RSA team to the road owner.

7. Prepare formal response

Typically the response from the road owner is a letter of action taken in response to the RSA team’s report. In some cases the road owner will accept and implement the recommendation; in other cases they will describe the reason for not taking the recommended action.

8. Incorporate findings

As appropriate, the road owner will implement the RSA team’s recommendations to improve safety in the current or upcoming work zone.

Promptness will be rewarded

An important tool for the work-zone RSA team is the prompt list, used in place of a lengthy, standards-based checklist. Prompt lists can be used for an RSA at any phase (planning, design or active work zone). A basic prompt list for an active work-zone RSA may include the following information:

• Warning signs

o Did you have enough advance warning of this work zone?

o Were the signs easy to understand?

• Flagger

o Did the flagger communicate with you clearly?

o Could you identify that a one-lane road was coming up?

• Signing

o Were the signs easy to understand?

o Was all signing accurate (e.g., “Left Lane Closed” on the sign actually came true in the work zone)?

o Were all electronic signs and arrow boards easy to read and understand?

• Overall setup

o Did the work zone look neat, clean and organized?

o Did the pavement marking, cones and barrels guide you through the work zone?

• Speed limit

o Did you feel comfortable driving at the posted speed limit?

o Did other drivers seem to be obeying the work-zone speed limit?

• Mobility

o Were you delayed more than is reasonable in this work zone?

o Did motorists make aggressive movements due to queues, delay (e.g., drive on shoulder, cross grass median)?

• Nighttime work

o Could you see well as you traversed the work zone?

o Was on-site work-zone lighting distracting?

Real-world examples

Though true work-zone RSA programs are in their infancy, some recent examples provide elements of RSAs that can be built upon for the future.

Work-zone RSA in Illinois

A group of researchers conducted a two-day work-zone RSA in 2007 as part of a research project. They analyzed a section of I-55 in Illinois to examine work-zone risk factors, including exposure, probability and consequence. RSA team members included participants from the FHWA, the Illinois DOT and the Illinois State Police. The team conducted two reviews, one during the day and one at night.

The work-zone RSA team discovered a number of safety issues that they presented to the road owner. Recommendations included the following:

• Remove conflicting striping;

• Add guardrail delineation;

• Flag “Trucks Use Left Lane” static signs to match the MUTCD;

• Consider adding changeable message signs for this truck message;

• Add speed-limit signs between lane tapers at needed locations; and

• Trim vegetation obscuring signs.

The RSA team developed a formal written report for the project owner.

Work-zone safety evaluation in Utah

In 2010 a group of researchers from Utah State University conducted a series of work-zone RSAs in Utah. Due to an identified issue in Utah, the researchers focused on the following safety-related elements at 11 work zones:

• Condition of temporary traffic-control signs;

• Crashworthiness of sign setup; and

• Pedestrian pathways.

During their field reviews of these active work zones, they identified the following potential safety problems:

• Equipment placed too close to the traveled way;

• Inadequate drum installation to delineate intersection turn lanes;

• Walkways blocked by work-zone-related signing;

• Pavement-marking deficiencies (nonexistent or confusing);

• Lack of advance warning signs;

• Edge drop-off; and

• Aggressive maneuvers by some drivers to bypass congestion.

Future of work-zone RSAs

The FHWA Office of Operations, under the Work Zone Safety Grant, is developing work-zone RSA guidelines and prompt lists to help state and local agencies conduct work-zone RSAs in their jurisdictions. For additional information, contact Chung Eng, FHWA, at [email protected] or 202.366.8043. TM&E

About The Author: Chandler is a senior transportation engineer in the Transportation Solutions Division of SAIC, Seattle. He can be reached at [email protected].

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