Kamm, Alta roundabout construction begins Nov. 27

Dinuba intersection of Kamm Ave and Alta Ave as seen from the sidewalk along Alta Ave, looking north across Kamm Ave. (Kenny Goodman)

Dinuba prepares to close the intersection at Kamm Avenue and Alta Avenue for at least three months to construct a two-lane roundabout near the new high school

DINUBA – Commuters and locals will need to find a new route through the south end of Dinuba for the next few months as one major intersection shuts down until spring. 

The intersection at Kamm Avenue and Alta Avenue will close to all traffic beginning Nov. 27 as a two-lane roundabout is constructed adjacent to the new Dinuba High School and a growing residential area. According to an announcement from the city of Dinuba, the road will be closed for three to four months, with an anticipated reopening date of March 4, 2024, pending weather.

“However, the contractor will be making every effort to have the intersection open earlier if possible,” the announcement said. “Alternate routes around and into Dinuba have been established.”

Kamm/Alta detours

The city is asking that vehicles traveling north into Dinuba from Visalia along Alta Avenue/Road 80 use Avenue 400 to head east to Road 88 or west to Road 56 to then continue north. Those going south to Visalia should use El Monte Avenue/Avenue 416 to access Road 88 or Road 56 and head south to Avenue 400 to continue along Road 80.

According to a detour map from the city, the local access route is along Road 74 and Road 72, west of Alta Avenue.

Construction details

Madera-based contractor Avison Construction will complete the work on the roundabout after the Dinuba City Council approved the award earlier this year. City Engineer Jason Watts told the city council at its meeting on Aug. 22 that city staff recommended the intersection be entirely closed during construction, as keeping it open would cost an additional $1.3 million and double the amount of time it would take to complete.

The entire roundabout will feature a pavement structural section, curb and gutter, sidewalks, pedestrian median islands, landscape, irrigation and other safety enhancements, Watts said. In total, the project will cost $4.4 million.

The city is using a combination of different funding sources to finance the roundabout project, including a $1.8 million grant, funds from SB-1 and Measure R — the half-cent sales tax for transportation that was passed in Tulare County in 2006 — and impact fees from the development of the new Dinuba High School.

The $1.8 million in grant funding came from the U.S. Department of Transportation’s Congestion Mitigation and Air Quality (CMAQ) Improvement Program. According to a city staff report, studies have shown that roundabouts reduce localized air pollution concentrations compared to other intersections by approximately 20%, which makes them a good candidate for CMAQ grant funding.

At the city council meeting on Aug. 22, Watts said the roundabout will have the same aesthetic design as the roundabout at Alta Avenue and Nebraska Avenue, which has received a lot of positive attention.

“We’re going to make a statement at this intersection as well,” Watts said.

Why a roundabout?

The plan for a roundabout at this intersection has been in the works for years; the city applied for the CMAQ grant in 2019 and awarded a contract to design firm 4Creeks, Inc. for the design of a roundabout at that intersection in December 2020.

When considering the design contract for the intersection in December 2020, the city staff report said the Dinuba Unified School District (DUSD) originally proposed to make modifications to the traffic signals to accommodate the increased traffic associated with the new school; however, the city believed a roundabout would be a better alternative because of studies that show increased safety tied to roundabouts.

According to that city staff report, roundabouts can reduce fatal traffic accidents by 90% and reduce pedestrian collisions by 40%. Further, roundabout maintenance and operation costs are lower than those associated with intersections with traffic signals.

The Federal Highway Administration (FHWA) lists roundabouts as a “proven safety countermeasure” because they improve safety by promoting slower speeds and traffic calming measures and they reduce traffic “conflict points,” which are areas where vehicles are merging, diverging or crossing with each other.

The roundabout design will have enhanced crosswalks with rectangular rapid flashing beacons to ensure pedestrian safety and will have median pedestrian islands to allow for pedestrians to stop in the middle of the crossing if needed. 

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