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Arrow Montana Demonstration Project: Innovative Culvert Rehabilitation Using Trenchless Technologies

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Data Acquisition and Analysis

Data collection and analysis on the MDT project consisted of acquiring and comparing data before, during, and after construction to provide sufficient performance information to support the feasibility of the proposed innovation and to demonstrate that innovative trenchless culvert rehabilitation technologies can be used to do the following:

  • Achieve a safer environment for the traveling public and workers.
  • Reduce construction duration and minimize traffic interruptions.
  • Achieve better quality because work is done in a controlled environment.
  • Attain user satisfaction.


The traditional culvert removal and replacement process involves excavating the roadway and removing the existing culvert, which requires lane closures and traffic control while pipes are being removed and replaced. This causes significant traffic disruption and exposes both the traveling public and workers in the work zone to safety hazards. One attribute of trenchless technologies is that they do not require lane closures during installation. As a result, these technologies provide no impact to traffic flow and a substantially safer environment for both the traveling public and workers.

Figure 23 shows a roadway during culvert rehabilitation using CIPP. No worker injuries or highway user incidents were reported during the rehabilitation of the culverts on MacDonald Pass. Overall, MDT exceeded all the safety performance goals set by HfL.

Figure 23. Typical CIPP liner installation.
Figure 23. Typical CIPP liner installation.

Contruction Congestion

The HfL performance goal criteria for construction congestion were easily attained because the project had no impact on traffic flow. All work was accomplished beyond the outside edge of the shoulders. Traffic was continuous during culvert rehabilitation, with no impact on trip time or queue length in the construction area.


The IRI and the tire-pavement interface noise at the project site were not impacted because innovative trenchless technology was used to rehabilitate the CSP culverts without disturbing the driving surface. Both CIPP and the HDPEP liners improve the structural integrity of the existing culverts and have a life expectancy beyond 50 years. The new lining system provides a smooth surface that reduces abrasion, enhances the flow of sediments through the culvert to the sediment basins, and maintains the culvert's hydraulic capacity. Cleaning the new catch basins will be easier, requiring less equipment and fewer workers than cleaning the bed load from the existing approximately 130 ft. long CSP culverts.

User Satisfaction

Because the trenchless culvert rehabilitation techniques did not interfere with traffic flow, MDT received no negative comments from the traveling public about the project and perceived that the public did not notice any work being done during the culvert rehabilitation process. Therefore, MDT's score for user satisfaction on a Likert scale is greater than 4 for both the approach used to rehabilitate the culverts and the final product. A questionnaire developed by MDT was sent to residents; for the results of the user satisfaction survey, see Appendix A.

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More Information



Mary Huie
Center for Accelerating Innovation

This page last modified on 04/04/11

United States Department of Transportation - Federal Highway Administration