Quantifying the Impacts of Utility Cuts on Roadway Pavements in the City of Saskatoon

It is with increasing frequency that agencies are faced with the impact utility cut installations have on their roadway networks. Utility cut installation often results in increased pavement roughness, pavement weakening, and accelerated deterioration. Agencies recognize these performance issues associated with utility cut installations and are aware of the impact they have on pavement asset value. To offset the impact of an accelerated requirement for pavement maintenance and rehabilitation activities, agencies often charge a fee for utility cut installations.

The City of Saskatoon faces these same challenges, and in 2017 initiated a study with the support of Tetra Tech to assess the impact utility cut installation have on their roadway network. The primary objective of this study is to determine if a reduction in pavement smoothness and distress ratings could be directly attributed to the installation of utility cuts. The secondary objective includes an assessment in quantifying a direct reduction in asset value resulting from the installation of utility cuts, and if so, correlate this reduction in asset value to an equivalent impact cost for utility cut installations; as a function of roadway classification.

Roadway condition data (International Roughness Index (IRI) and Pavement Condition Index (PCI)) were assessed in the years 2014 and 2017. The City's roadway network was categorized into sections that had utility cuts installed between 2014 and 2017, and sections without utility cuts. Detailed data analytical tools were utilized, and regression analysis and linear regression equations were established for various roadway classes between 2014 and 2017 to determine if the impacts of utility cut installations could be quantified. For example, IRI values increased as expected for all categories of the roadways (Local Roads, Collector Roads, and Arterial Roads) regardless of whether utility cuts were installed from 2014 to 2017. However, a greater increase was noted for the roadways with utility cut installations compared to those without utility cuts. Statistical analysis was conducted, and the difference in IRI and PCI degradation is significant between roadways with utility cuts and those without utility cuts.

Conclusions from this study showed that in impact of utility cut installation can be quantified, and an associated reduction in roadway asset value can be calculated. This paper provides a background to the analytical tools utilized in completing this study, the resulting impacts on roadway condition, and a summary of the influence utility cuts have on asset condition and value.