Twin tunnels environmental assessment and section 4(f) evaluation, Clear Creek County

The Twin tunnels project proposes to add a third eastbound travel lane on I-70 between the Idaho Springs East Interchange (milepost 241) to the base of Floyd Hill (milepost 244) where a three-lane highway section currently exists. The project is approximately two and a half miles long and includes widening the eastbound bore of the Twin tunnels.