According to news reports, construction is scheduled to begin this week on the westbound tunnel project (the twin tunnels before Idaho Springs).
The Westbound I-70 Twin Tunnels project will widen the westbound bore of the tunnel in Idaho Springs to about 53-feet. This will accommodate a third lane along westbound I-70 when the highway is eventually widened. Unlike the recent work done along eastbound I-70 to add a third highway lane from Idaho Springs to the bottom of Floyd Hill, this project will only widen the tunnel to accommodate a future third lane. It does not include expanding westbound I-70 to three lanes at this time.
In March, eastbound I-70 will be reduced to two lanes of travel so crews can put down temporary pavement in the center median area on both sides of the tunnel to shift westbound traffic into the eastbound lanes.
In mid to late March there will be minor blasting activity that will require stopping traffic in both directions for about 15 minutes.
In late March there will be rock scaling work done to remove large rocks from the mountain face above the highway. This work will require stopping traffic in both directions for up to 30 minutes.
In April, eastbound I-70 traffic will move back onto the detour route around the tunnel and westbound traffic will start moving through the eastbound tunnel.
Check cotrip.org for info on delays, closures, etc.