CENTENNIAL —Brace yourselves, south metro drivers: A 20-month reconstruction of the Interstate 25 and Arapahoe Road interchange is coming.

The $68-million project is expected to start in April 2016, with crews hoping to be done by the end of 2017, officials working for the Colorado Department of Transportationrecently announced.

The project will rebuild the bridge that carries I-25 over Arapahoe Road, add one additional through-lane to both eastbound and westbound Arapahoe Road under the bridge and add many other traffic improvements to the crowded corridor on the border of Centennial and Greenwood Village.

Tony Marcello is the project manager with CDOT engineering contractor David Evans & Associates Inc. He and other officials held an open house last week covering the project.

“There were a lot of safety issues with this interchange,” he said, referring specifically to traffic backups onto I-25 that should be lessened by the new design. “During peak traffic hours, traffic queues back up all the way onto the southbound off-ramp, impeding traffic on the highway. That’s a safety issue.”

The new design calls for a longer southbound off-ramp and adds a third-left turn lane at the end of it, hopefully passing traffic from southbound I-25 through the area more efficiently, Marcello said.

Marcello said delays on I-25 will be mitigated by building the new bridge in three phases, confining traffic to some parts of the bridge to accommodate the work on other parts. Arapahoe Road will have some full closures, but those should all be overnight, he said.

“I-25 will have all its lanes,” Marcello said. “There will be some reduced lane width and shoulder width, but all lanes will be open.”

CDOT Project Manager Telecia McCline noted the project is not just dealing with I-25 but other busy Arapahoe Road intersections including Yosemite and Boston streets and Clinton Court. Those intersections are being addressed to improve traffic flows. Northbound Yosemite, for instance, will be widened and a second left-turn lane onto westbound Arapahoe will be added.

“Safety is our biggest concern here. Slow for the cone zone,” McCline said of the project, urging patience for drivers. “We want everyone to get home safe at the end of the day.”

Former Centennial City Councilwoman Andrea Suhaka attended the open house. She has lived in the Walnut Hills neighborhood, southwest of I-25 and Arapahoe, for 42 years. Walls are being installed along Yosemite and Arapahoe to block noise in her neighborhood.

Suhaka was critical of the plans. She thinks the triple left-turn lane from southbound I-25 will cause backups for those seeking to turn right. But she is happy the project is nearly underway.

“This stuff can’t happen fast enough,” she said. “The traffic counts in this area are mind numbing.”

CDOT will be acquiring pieces of right-of-way from numerous businesses — both temporarily and permanently — to accommodate the work. Only one business — Pat’s Philly Steaks & Subs at 9211 E. Arapahoe Road — has been targeted for demolition and relocation. The owner of that business was not available to comment.

Among the portions of the project slated to start first is the realignment of the existing frontage road on the east side of I-25 north of Arapahoe into a new portion of South Alton Way that will go wide of the businesses there and connect Arapahoe with East Southtech Drive to the north.

Chris O’Sullivan co-owns the Brothers BBQ restaurant located near the existing frontage road. He said the work could eventually open his business to new customers to the north and east. In the meantime, he is optimistic customers will keep finding his business just as they did during the massive T-REX highway construction project last decade..

“People have supported us even with the tricky access we have now. CDOT has promised we will have access at all times with this project,” he said. “You just don’t want people to avoid the area all together, so if they can address the congestion, that’s a good thing.”

Joe Rubino: 303-954-2953, jrubino@denverpost.com or @RubinoJC

For more information

Visit the project website at codot.gov/projects /I25-Arapahoe or call 720-225-4651.