Texas A&M Transportation Institute

Transportation Policy Research

Reducing Construction/Maintenance Disruptions

Construction Improvements

Description

Construction and maintenance on congested freeways create major disruptions in traffic flow. Reducing construction disruption strategies lessen the negative effects of construction and maintenance on traveler safety and mobility. Reducing the disruption:

  • Minimizes additional congestion.
  • Lowers project costs.
  • Reduces required construction time.
  • Decreases the overall frustration felt by drivers and businesses due to the project.

Two of these strategies include a transportation management plan (TMP) and zipper merge.

A TMP best accomplishes this disruption reduction. A TMP coordinates the efforts of several parties and guides public expectations. A TMP includes three plans for controlling and managing traffic during the project:

  • A temporary traffic control plan that defines the type and location of traffic control devices used to guide traffic through the work zone.
  • A transportation operations plan that defines the strategies to be applied within the work zone and on alternative routes to ease traffic congestion in the work zone.
  • A public information plan that defines what information to communicate to the public before and during the project and how to communicate it.

A TMP helps agencies identify which projects to perform on nearby roadways to improve capacity or traffic flow before a major project begins.

All significant federal-aid projects require a TMP. A significant project is “one that, alone or in combination with nearby concurrent projects, is anticipated to cause sustained work zone impacts greater than what is considered tolerable based on state policy and/or engineering judgment.”1

The zipper (also late or joint) merge uses signs to tell drivers to use both lanes until a merge must occur. Merging too soon can cause needless backups and delay in construction zones. It also encourages rear-end and sideswipe crashes and makes drivers angry. Signs and arrows direct drivers to take turns at the merge point. This shortens the length that cars are using a single lane. The difficulty with the zipper merge is convincing drivers that waiting to merge is ideal.

Executive Summary

Target Market

This strategy works best in projects with expected unacceptable work zone impacts. Deciding what is unacceptable depends on the features of the region, the type of work being done, and other factors. Any construction location where the work may interfere with traffic flow should have a TMP.

How Will This Help?

  • Lessens congestion and reduces delay—Construction creates or significantly increases congestion on high-volume routes or on other nearby routes. A TMP requires all affected agencies to consider the impacts of construction on congestion and come up with ways to lessen those impacts. The plan also identifies co-reliance between strategies and a critical timeline for startup.
  • Increases safety—Construction congestion contributes to rear-end crashes and accidents with construction workers. A TMP that lessens congestion reduces these dangers.
  • Speeds up construction—Many construction tasks require timely delivery of materials. Traffic congestion delays material delivery and increases the number of delivery vehicles in order to maintain a desired rate of production. A TMP can show how travel times during periods of construction activity will stay at acceptable levels. The TMP will also aid contractor productivity.

Implementation Examples

Available FHWA Guidance—After it started requiring TMPs for major projects, FHWA emphasized developing products to help state and local agencies obey the new regulations. Developing and Implementing Transportation Management Plans for Work Zones1 provides useful advice on the:

  • TMP development process.
  • TMP performance assessment.
  • TMP potential components.
  • Available impact management strategies.

A simple checklist of potential TMP components helps guide agencies through the development process. In addition, a TMP strategy matrix helps an agency consider the types of impacts they want to lessen, triggers, and potential challenges.

Transportation Management Plan Requirements2—This instructional and information memorandum from the Virginia Department of Transportation presents a specific process for developing TMPs for state contracts. It outlines key roles and responsibilities of various involved individuals and entities. It also outlines detailed site conditions to check for strategy appropriateness.

Zipper Merge Usage in Colorado and Minnesota—Both the Colorado Department of Transportation and the Minnesota Department of Transportation have adopted zipper merge strategies in their respective states. Both found a need for education and public outreach programs to inform drivers:

  • That this behavior is desirable.
  • How to properly perform the maneuver.
  • That it reduces congestion.
  • That it improves safety.

Study data in Colorado showed that late merges can reduce traffic lines in construction zones by up to 35 percent. A study from Louisiana State University3 simulating the merge found that average speeds were 6 percent higher, braking force was 34 percent lower, and overall, drivers were more aware and relaxed in their surroundings.

Application Principles and Techniques

A TMP identifies and executes strategies that reduce construction and maintenance disruption. Those strategies under the temporary traffic control plan include:

  • Various control techniques and devices.
  • Project coordination.
  • Contracting.
  • Innovative construction methods.

Under the public information plan, various public awareness and motorist information strategies are available. Finally, under the traffic operations plan, various mitigation plans exist to promote:

  • Demand management (encouraging both departure time and diversions).
  • Corridor or network operations plans.
  • Work zone safety management plans.
  • Traffic incident management and enforcement plans.

An effective TMP must recognize the relationships between the various plans available for use. Certain plans work best when combined. For example, a project might require both high-occupancy vehicle priority ramps and lanes through the work zone or on alternative routes. However, combining strategies can also be ineffective if the plans overlap. For example, adding both additional buses and light rail cars to a transit system during construction may result in less use of transit than if only one of them is added.

Implementation Issues

There are no major issues associated with developing a traffic management plan. Planners must communicate with and include all parties early in the process in order to ensure that the plan covers all elements of the project, including:

  • Utility management.
  • Safety.
  • Incident management.
  • Emergency services.
  • Law enforcement.
  • Public awareness.

When performing a zipper merge, agencies should educate drivers on the process, including how and why it works better than past behaviors. Agencies should also consider compliance measures to ensure successful deployment.

Who Is Responsible?

The operating agency starting the construction or maintenance work is primarily responsible for TMP development and execution. However, a TMP requires buy-in and assistance from all affected parties. Many TMPs in urban areas are multi-jurisdictional and involve public-private partnerships.

Project Time Frame

The time required to develop and execute a TMP depends on the type of plan used. For very large projects on highly congested roadways, a year or more lead time may be required to apply the plans on alternative routes. In such cases, two years may be needed for TMP development prior to the actual start of work. Easier projects may need only a few months to apply the necessary easing strategies to the roadway. In that case, a TMP may be needed only several months to a year prior to the start of construction.

Cost

The cost of a TMP depends on the size of the project and area impacted by construction, as well as the implementation plans. FHWA allows mitigation plans to be paid for as part of construction project expenses.

Data Needs

TMP development depends on a reasonable estimate of traffic impacts within the route being considered. Data needs vary for impact assessment by type of tool (network-based planning models, microscopic simulation tools, etc.). Information on the costs of the various plans is also needed. Finally, monitoring and evaluating the TMP can assist in making improvements or applying lessons learned from one project to the next.

Reducing Construction/Maintenance Disruption Best Practices

  • Type of location: Anywhere a significant project affects traffic beyond tolerable conditions.
  • Agency practices: Involve all parties potentially affected by the project and consider multiple projects together, when appropriate. Recognize any interdependencies in mitigation strategies to be implemented.
  • Frequency of reanalysis: Before any significant construction project begins.
  • Supporting policies or actions needed: Multi-jurisdictional agreements, dedication to involve all affected parties.
  • Complementary strategies: Construction contracting options, traveler information systems, aggressive incident clearance, innovative construction methods, active traffic management, and travel option strategies.

For More Information

Scriba, T., P. Sankar, and K. Jeannotte. Implementing the Rule on Work Zone Safety and Mobility. Report FHWA-HOP-05-065, FHWA, U.S. Department of Transportation, Sept. 2005. http://ops.fhwa.dot.gov/wz/rule_guide/tech_report.htm.

Transportation Management Plan Guidelines. Division of Operations, California Department of Transportation, Sacramento, CA, June 2009. http://www.dot.ca.gov/hq/traffops/trafmgmt/tmp_lcs
/files/TMP_Guidelines.pdf.

Traffic Mitigation Guidelines for Work Zone Safety and Mobility. New Jersey Department of Transportation, Trenton, NJ, Oct. 2007. http://www.nj.gov/transportation/eng/documents/BDC
/pdf/attachmentbdc07t07.pdf.

References

  1. Jeannotte, K., and A. Chandra. Developing and Implementing Transportation Management Plans for Work Zones. Report FHWA-HOP-05-066, FHWA, U.S. Department of Transportation, Dec. 2005. http://www.ops.fhwa.dot.gov/wz/resources/publications/trans_mgmt_plans/trans_mgmt_plans.pdf.
  2. Transportation Management Plan Requirements. Report IIM-LD-241.4, Virginia Department of Transportation, Richmond, VA. http://www.vdot.virginia.gov/business/resources/traffic_engineering
    /memos2/TE-351.2_Transportation_Management_Plan_Requirements.pdf    .
  3. The Joint Merge: Improving Work Zone Traffic Flows. UTC Spotlight. Office of Research, Development and Technology, U.S. Department of Transportation, Washington, DC, July 2013.