Moving Idaho 55 from its current route through town to Deinhard Street and Boydstun Lane is under study by the City of McCall and the Idaho Transportation Department.
The proposal would see the city and ITD swap ownership of the corridors in order to divert Idaho 55 traffic around the town.
Over the last 20 years, the number of vehicles passing through downtown McCall on Idaho 55 increased from an average of 8,800 per day to 11,000 per day, according to a study of the proposed exchange presented recently to the McCall City Council.
That volume can be reduced if traffic now going through downtown was diverted to Deinhard Lane and Boydstun Street, the study said.
Millions of dollars would need to be spent to bring both corridors up to the standards required by both agencies, but completing those improvements would not be required before the swap can take place, District 3 ITD Administrator Caleb Lakey said.
Work included in the study is “not meant to be a checklist” of requirements to swap ownership of the roads for a state highway bypass of McCall, Lakey said.
Airport “S” curve
One of the biggest obstacles facing the proposed exchange would be straightening the “S” curves on Deinhard Lane near the McCall Fire & EMS station which do not meet standards for a state highway.
The curves were built to meet Federal Aviation Administration requirements to separate the road from the end of the runway at McCall Municipal Airport to reduce the risk of collisions between cars and airplanes.
The only way to keep the separation while straightening the curves would be to extend the runway further south.
But the FAA, the main source of funding for airport improvements, will not pay for an extension, said Allen Kenitzer, a Federal Aviation Administration spokesperson.
“A runway shift to the south to accommodate moving the road closer to the existing runway would not qualify for FAA funding,” Kenitzer said.
Realignments of Deinhard Lane that do not require moving the runway were not included in the bypass study, but alternative options exist, Lakey said.
“The concept of the bypass does not hinge on relocating the runway,” Lakey said. “It is a consideration, but there are other ways to address the road corners besides moving the runway.”
Up to about $2.8 million would be needed to improve intersections at each end of the proposed by-pass route, according to estimates in the study.
One concept for the intersection of Boydstun Street and Idaho 55 would add a roundabout at a cost of about $1.7 million.
Another option for that intersection costing $686,000 would widen lanes the existing Idaho 55 to add a left turn lane onto Boydstun Street and infrastructure for a future stoplight.
The intersection of Deinhard Lane with Idaho 55 at the south end of McCall would need a free right turn lane which would allow traffic to merge into southbound traffic without stopping for the traffic light, the study said.
That option would cost about $910,000, but a cheaper option costing about $500,000 would widen the southwest corner of the intersection to more easily allow semi-trucks to turn.
About $17 million would need to be spent in the 2.4-mile Idaho 55 corridor through McCall, according to the study. About half that cost would be for sidewalks, lighting, pedestrian ramps and bicycle lanes.
That would include sidewalks, curb and gutter, bicycle lanes and pedestrian ramps on both sides of Third Street from Deinhard Lane to Colorado Street.
West Lake Street from Albertsons to beyond Warren Wagon Road would be improved with bicycle lanes and a combination of sidewalks and separated pathways, according to concepts in the study.
About $4.4 million in stormwater improvements would filter runoff that currently drains directly into Payette Lake from eight areas along Lake Street.
About $1.6 million would be used to add a center turn lane on Third Street from Deinhard Lane to Colorado Street. Turn lanes from West Lake Street onto State Street and Gamble Road would also be added. About $3 million would be needed for repaving and moving utility lines that could conflict with new bicycle lanes or sidewalks.
The study was conducted by Horrocks Engineers of Meridian, the city’s contract engineer. The study cost $84,000, of which $34,000 was paid by the city while the state paid $50,000.