One RA-400 Spray Patcher is capable of repairing more than 200 potholes in a single day, according to LeeBoy. Photo courtesy of LeeBoy

One RA-400 Spray Patcher is capable of repairing more than 200 potholes in a single day, according to LeeBoy. Photo courtesy of LeeBoy

Since the City of Lincoln, Neb., first deployed its four Rosco RA-400 Patcher trucks in May 2016, the city has slashed the amount of employee hours required for pothole repairs and the need for disruptive street closures. Additionally, the new patches — composed of hot emulsion and aggregate — have held much better than patches made in previous years.

Saving Time and Labor During Pothole Patching

“We’re just very, very pleased with them,” said Ty Barger, public works maintenance manager for the City of Lincoln, when asked about the Rosco RA-400. “Ever since we purchased them we’ve not had to utilize manpower surges for pothole efforts following the freeze-thaw cycle. We typically had to do that in winters prior to fielding these machines.”

Previously, the Lincoln Public Works and Utilities Department relied on four-man crews that used hot-mix or cold-mix asphalt for street pothole repairs. This traditional approach wasn’t just labor-intensive and time-consuming — it required lengthy street closures that inconvenienced residents. Additionally, most of the patches would eventually come loose — sometimes multiple times within the same year, Barger said.

In contrast, the Rosco RA-400, manufactured by LeeBoy, requires a single operator to make pothole repairs, and the employee never has to leave the safety of the truck cab.

The RA-400 patching boom extends and retracts, providing a wide patching range. Using a joystick in the truck cab, the operator controls the four-step spray injection process. Screenshot courtesy of City of Lincoln

The RA-400 patching boom extends and retracts, providing a wide patching range. Using a joystick in the truck cab, the operator controls the four-step spray injection process. Screenshot courtesy of City of Lincoln

The Spray Patcher's Four-Step Spray Injection Process

Powered by a Kubota Tier 4 Final 65-hp diesel auxiliary engine, the RA-400’s telescoping delivery boom extends and retracts to perform a four-step spray injection process that the operator controls with a joystick.

First, a hydraulically driven, high-volume blower cleans the pothole. Second, a tack coat of emulsion is applied to the area. Third, a mixture of aggregate and hot emulsion fills the pothole. And fourth, a finish coat of dry aggregate is applied. The whole process takes about a minute, so arterial road or residential street closures aren’t necessary. The patch is immediately ready for traffic flow.

Moreover, the emulsion patching material has proven to be more rugged than the traditional hot-mix or cold-mix asphalt.

“These patches are staying in,” Barger said. “We’re not having to go back to replace them.”

The RA-400 spray patchers have allowed the department to make pothole repairs quicker and with fewer resources, freeing crews to complete a higher volume of permanent repairs. The city chose the Rosco RA-400 after consulting with Knox County, Neb., a jurisdiction that also uses the model. After about a week of training and practice, operators were up to speed and ready to hit the streets, Barger said.

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