Construction workers are putting the finishing touches on an extension of Ridgegate Parkway that provides another connection between Lone Tree and Parker.

The $8-million project is expected to divert thousands of vehicles off of Lincoln Avenue the day it opens. Officials from Douglas County and Lone Tree initially planned on completing the extension several years down the road, but intergovernmental cooperation and a drop in the cost of construction has Ridgegate Parkway opening the morning of Dec. 13.

Those who made the much-needed, 3.5-mile connection happen will attend a ribbon-cutting at 9 a.m. where Ridgegate Parkway meets South Peoria Street just east of Interstate 25.

Douglas County, which contributed $5 million to the project, is clearly excited about the improvement of traffic flow in the northern tier, calling Ridgegate Parkway a “mutually beneficial addition to the county’s transportation infrastructure that relieves traffic congestion on Lincoln Avenue between I-25 and Parker Road and provides economic development stimulus to the corridor.”

The road runs through land owned by the Coventry Development Corporation, which developed the initial stages of RidgeGate, including Super Target and Sprouts Farmers Market near Lincoln Avenue and RidgeGate Parkway.

The parkway becomes Yosemite Street north of Lincoln Avenue; it will connect with the existing extension of East Mainstreet as it reaches Parker.

John Cotten, director of Lone Tree Public Works, did not have specific estimates, but said he expects a good flow of traffic on RidgeGate Parkway on opening day.

“We’re interested to see ourselves,” he said, when asked for projected vehicle counts.

Initial estimates put the number around 15,000 vehicle trips per day. Sean Owens, a road engineer who oversaw the project for Douglas County, was not immediately available for an updated estimate.

Traffic counts will continue to build as those who commute from Elbert County and southern areas of Douglas County discover the route. Lincoln Avenue carries as many as 60,000 vehicle trips per day and becomes bogged down with traffic during morning and evening rush hours.

The Lincoln Avenue interchange with I-25 will also benefit as many drivers will begin using the Ridgegate Parkway interchange instead. A team of consultants from Felsburg, Holt, Ullevig projected that motorists will save approximately $2 million per year in reduced public commute time with the opening of the extension.

The City of Lone Tree managed the design and construction of Ridgegate Parkway East between I-25 and Peoria Street, and Peoria Street from Crescent Moon Parkway to Ridgegate Parkway to provide additional access to Lincoln Avenue. The county managed the construction of the extension of Ridgegate Parkway/East Mainstreet between Peoria Street and Meridian Village Parkway.

Cotten credited the cooperative efforts of Lone Tree, Douglas County, the Southeast Transportation Management Authority, SPIMED and Coventry for the early completion of the road.

Douglas County Commissioner Jack Hilbert and Lone Tree Mayor Jim Gunning, members of the Southeast Transportation Management Authority, obtained a $2.5-million grant from the Southeast Project Investment Metro District by detailing the potential benefits of the road to the region. Douglas County also put up $2.5 million in matching funds. Coventry will reimburse the county for the remainder of the construction cost once development begins along the Ridgegate Parkway corridor.