Loveland Pass

Loveland Pass carries US-6 over the Continental Divide in Colorado at 11,990 feet, the highest pass in the state that stays open through the winter. It sits about 800 feet above the Eisenhower-Johnson Memorial Tunnel that takes I-70 under the divide, and it is the road every placarded hazmat truck has to take, because tankers and other placarded loads are banned from the tunnel year-round. Over-height rigs taller than the tunnel's 13 feet 11 inches detour over the top too. On an average day around 200 hazmat trucks climb the pass while roughly 30,000 vehicles run the tunnel below.

This is a two-lane mountain road with a steady 6.7 percent grade and a stack of tight hairpin switchbacks on both sides of the summit. There is little margin and not much guardrail. The Colorado State Patrol describes it as self-policing: trucks crawl up and drivers slow way down, which is part of the point of sending placarded loads over an open road instead of through a confined tunnel. The reason behind the ban is fire. CDOT's analysis found a gasoline fire could put out about 100 megawatts of heat, while the tunnel is built for 20.

• Summit 11,990 ft on US-6, the highest Colorado pass kept open all winter
• The mandatory year-round route for placarded hazmat trucks banned from the Eisenhower-Johnson Tunnel on I-70
• Steady 6.7 percent grade with hairpin switchbacks on both sides; about 800 ft higher than the tunnel
• Roughly 200 hazmat trucks a day take the pass; the tunnel below handles about 30,000 vehicles (Summit Daily)
• Commercial vehicles must carry chains on I-70 from Dotsero (MP 133) to Morrison (MP 259), Sep 1 to May 31 (CDOT)

Colorado's commercial chain law covers the I-70 corridor that feeds the pass. Every commercial vehicle on I-70 between Dotsero at milepost 133 and Morrison at milepost 259 has to carry chains from September 1 through May 31, and getting caught without them runs about $100 plus a surcharge. When CDOT and the State Patrol activate the Code 18 chain law in a storm, anything rated 26,001 pounds or more has to put chains on at least four drive tires before going on. The formal chain stations sit on the I-70 approach, at Herman Gulch, Bakerville, and Georgetown, with the Dillon chain station and brake-check on the west side. US-6 over the summit is a two-lane state highway without that network, so chain up before you start the climb. The pass closes case by case for avalanche control, whiteouts, wrecks, and slides, and because it is higher and more exposed than the tunnel, it usually closes first. When it does, CDOT escorts the hazmat loads through the tunnel in a convoy at the top of each hour and holds the rest of I-70 while they pass.

The pass takes its name from William Loveland, president of the Colorado Central Railroad, and the first usable trail over it was finished in 1879. Crews paved the modern road in 1949 and 1950, decades before the tunnel opened beneath it.

When the Eisenhower-Johnson Memorial Tunnel carried I-70 under the divide, it cut 9.1 miles off the US-6 route, but it left hazmat carriers, over-height trucks, bicycles, and pedestrians up top, and they still climb the pass today. The mountains here are not forgiving. An avalanche near the pass on April 20, 2013 killed five backcountry snowboarders, the deadliest in Colorado since 1962.