Auburn’s average, local street is in good shape.

Which is a fine thing, as City Engineer Jacob Sweeting assured the Auburn City Council recently at City Hall. That says the city is getting a lot of years out of its pavements, saving money on preservation and maintenance.

Sweeting grounded that positive message on the latest Pavement Condition Index, PCI, findings. The system scores pavement from 100 at brand-new all the way to zero, where it has devolved to gravel and dirt.

Sweeting said the overall PCI increased from 68 in 2018 to 70 in 2019, with 70 or fair being the overall target.

“That’s great,” Sweeting said, “but it’s not necessarily the whole story.”

The pill is that Auburn’s collector roads, which make up slightly more than half of the total, equivalent lane miles of roadways throughout the city, rate an overall PCI of 68, and arterial roads an overall 62.

That matters because the city targets an overall PCI of 70 to maximize pavement life and minimize maintenance and preservation costs.

Failing to make the target could cost the city and its residents a pile of money.

Here’s why.

Once the PCI of a roadway has dropped below 70, additional patching and replacement of the top layer of pavement – overlay or grind and overlay – is needed to bring the pavement back into “good condition” and extend the life of the pavement.

Without these pavement preservation efforts, the PCI continues to decrease and the costs to bring the pavement back into “good condition” increase.

Additionally, as the PCI decreases, more and more potholes pock the roadways. which requires more and more temporary and permanent pothole repair.

Without preservation activities, the PCI will drop below 40, the roadway drops to “poor condition” and needs an expensive, full re-build.

Arterial streets are further classified as either principal or minor arterials. Typically, principal arterials are much more competitive in grant competitions than minor arterials. For this reason, principal arterials are in overall better condition (64 PCI) than minor arterials (60 PCI).

So the question becomes, Sweeting said, how to get the collectors and arterials up to 70?

Well, it won’t be cheap.

“The basic modeling that we’ve done so far indicates that if we want to get there in 10 years, it would be a total of $70 million or $7 million per year for 10 years, which is higher than we have ever funded the program, and probably beyond the scope of most grant programs that are out there,” Sweeting said.

The arterial and collector preservation programs rely heavily on grant funding, and the city hasn’t secured any grant funding for beyond 2021, Sweeting said

Deputy Mayor Claude DaCorsi asked Sweeting what such a large preservation program would mean in terms of future staffing levels.

“Certainly, with the resources we have now,” Sweeting replied, “it would be beyond reach. With a program that big, we would probably need to have a dedicated team working solely on those preservation programs.”

“Are there any cities around here that have 70 or higher?” asked Councilmember Chris Stearns.

Sweeting replied that Auburn is actually “one of the better cities,” as not all cities have been collecting data as long as it has, and reporting that data, like Auburn does.

“But our local streets being above 70 is very significant, and reflects the funding levels that the council has provided to that program for several years, and it has paid off,” Sweeting said.

Periodically, the city performs citywide inspections to determine the PCI for each roadway it maintains. The PCI inspections were completed in 2013, 2017, and in the summer of 2019. The PCI inspection data is used to plan pavement preservation activities and as a gauge to measure how overall roadway conditions have, and will, respond to different funding levels and other factors that impact roadway conditions such as new development, City and non-City utility work in roadways, truck traffic, pavement design (past and present), and weather conditions.

Additional information is available on the city’s website, which provides a more in-depth explanation of the city’s street preservation programs. including program history, projects, funding, and technical considerations: auburnwa.gov/cms.