One-Call Centers

This blog series Technology Highlight explores some of the ways that investments in innovation lead to better outcomes for infrastructure and public safety. When technology advances, it often becomes cheaper, more widely available and accessible, and helps facilitate faster, safer, and greener projects.

This series launched by highlighting the way that innovation leads to greater access to technology. Using mobile devices as an example, we saw the way that innovation and competition drove down prices and improved quality to such an extent that cell phones went from bulky, single-function devices for the rich and connected to slim, powerful, and multifunctional computers in the hands of virtually anyone who wants one.

This has led to overall economic development and improvements across the infrastructure space, but has particularly benefited damage prevention and facility safety. By facilitating high quality information sharing and enabling real-time collaboration, mobile devices are not only communication devices; they are damage prevention essentials.

Obviously mobile devices play into damage prevention in a number of ways. At the most basic level, if we start at the very beginning, phones allow excavators to place a call to 811 – the state One-Call center tasked with notifying utilities about proposed excavation. Data shows that when a call is made, damage is avoided up to 99 percent of the time. That impressive statistic is only possible because of innovative technology. This blog takes a step back to explore the damage prevention process from the beginning.

When a homeowner, contractor, or professional excavator plans to break ground, they are required to call 811 or utilize the website forms from the state One-Call center. From there, the center collects information on the proposed excavation and sends notifying transmissions to all utilities with underground infrastructure in and around the proposed dig site.

In past decades, One-Call centers may have had to utilize paper maps, sketches, address books, survey plats, and other physical documents to identify and cross reference a dig site with known underground facility locations. With improvements in everything from digital photography to global positioning systems and aerial imagery, this paper-heavy process is no longer the norm.

Today, digital records exist for both sides of the equation – the excavation sites and the underground facilities. The One-Call center simply checks the overlap to know which public utility or facility owner to contact.

It all starts when utilities share their records with the One-Call center, by uploading digital polygons to represent their subsurface infrastructure. These are two-dimensional shapes provided to the center with a buffer zone around them – for instance a pipeline may be only a diameter of a few inches, but may be represented to scale with several feet on either side. This helps ensure that the utility receives notification when a proposed excavation site is anywhere near the pipeline.

When excavators describe or draw their proposed site, the One-Call center operator will also create a polygon in the center’s database. These polygons are also exaggerated with large buffers – when work is being done at a single house, the center may provide a notification polygon that is several houses wide. This ensures that any and all utilities that could possibly be impacted are notified.

When an overlap exists between the excavator’s description – as represented by the One-Call center’s notification polygon – and the utility provided polygon, the One-Call center sends a transmission to each utility. There are often as many as five to seven utilities notified for a single excavation.

The powerful software, which incorporates GPS, residential maps, facility maps, and more, saves time and resources to ensure that locators can be sent to mark the excavation site in a timely manner. What may have taken far longer and with more energy years ago – comparing and cross referencing maps – can be done in a matter of seconds today through One-Call center computers.

The impressive 99 percent damage avoidance is possible because this process utilizes precision computing and sophisticated cross referencing to notify all possibly implicated utilities and ensure they properly mark the excavation site. From there, avoiding damage requires still more technology and best practices. In the next blog, learn about the locating equipment that helps to accurately identify the presence and location of subsurface infrastructure onsite.


Written by Benjamin Dierker, Director of Public Policy


Interested in other technology highlights? Stay tuned for more ways technology is making damage prevention safer.


The Alliance for Innovation and Infrastructure (Aii) is an independent, national research and educational organization. An innovative think tank, Aii explores the intersection of economics, law, and public policy in the areas of climate, damage prevention, energy, infrastructure, innovation, technology, and transportation.