As fall turns to winter, I-70 Mountain Corridor travelers need to prepare for a familiar seasonal challenge: sun glare at Floyd Hill.
Beginning Nov. 1, and continuing through February, bright morning conditions may require eastbound I-70 traffic to be detoured at Floyd Hill, approximately Mile Points 244 to 248 east of Idaho Springs, between 6:30 and 8:30 a.m.
Formerly referred to as a “sun glare closure,” the safety measure is now called a sun glare detour because traffic doesn’t stop. Instead, motorists are rerouted off eastbound I-70 at the bottom of Floyd Hill. From there, travelers can continue east on US 6 through Clear Creek Canyon or use the eastbound frontage road, US 40, to re-enter I-70 at Beaver Brook (Exit 248). When a detour is necessary, travelers should prepare for delays of up to an hour.
Anyone who has traveled eastbound I-70 over Floyd Hill on a bright winter morning knows just how intense the sun can be. During the fall and winter months, the sun sits low on the horizon during the morning commute, and at Floyd Hill, its angle can shine directly into drivers’ eyes and significantly reduce visibility and create a safety hazard.
Several factors unique to the mountain corridor can make conditions even more challenging. Rain, melting snow or liquid roadway treatment materials can reflect sunlight and amplify glare, while Floyd Hill’s steep grades and sharp curves can reduce visibility and stopping sight distance. Wildlife, stopped vehicles, debris and other unexpected hazards can also be difficult to see when drivers are temporarily blinded by the sun.
That’s why a detour isn’t automatically implemented every sunny morning. Colorado State Patrol and Colorado Department of Transportation personnel stationed near Floyd Hill evaluate conditions each morning and determine on a case-by-case basis whether visibility has created an unsafe driving environment.
With major improvements underway as part of the I-70 Floyd Hill Project, travelers may wonder why the Project can’t simply eliminate the sun glare problem. The Project design team considered how roadway improvements could address the issue, but there isn’t a practical engineering solution.
To significantly change how the rising sun hits drivers, the alignment of I-70 would need to be dramatically shifted, which isn’t feasible given the surrounding mountain terrain. Sun glare is one of the realities of mountain travel, much like snow, ice and fog. Roadway improvements can make the corridor safer and more efficient, but some conditions created by Mother Nature simply can’t be engineered away.
In fact, managing sun glare at Floyd Hill predates the current construction project by decades. In the 1990s, before standardized protocols existed, CSP troopers stationed near Floyd Hill manually held or slowed traffic when blinding morning glare contributed to an increase in crashes. As commuter and freight traffic increased along the I-70 Mountain Corridor, CDOT and CSP established a more structured safety protocol in the early 2000s. The seasonal program has since become a proactive safety measure when low morning sun creates unsafe visibility conditions.
If your trip takes you on eastbound I-70 through Floyd Hill on a sunny morning between November and February, plan ahead and build extra time into your trip. Before heading out, check current roadway conditions and travel times on COtrip.org or the COtrip Planner app.
If you encounter bright glare while driving, slow down, increase the distance between your vehicle and the one ahead, use your sun visor and sunglasses, and make sure your windshield is clean.
A sun glare detour may add time to your morning trip, but a little patience and preparation can help everyone travel the I-70 Mountain Corridor safely this winter.