Trail Ridge Road in Rocky Mountain National Park closed on Tuesday for the season. 

Bicycles and leashed pets can still use the road, which spans 48 miles from the park entrance on the east at Estes Park to the west entrance at Grand Lake, through Nov. 30.

Around 11 miles on this roadway is above the tree line and near 11,500 feet, where winter conditions like drifting snow, high winds and freezing temperature are common.

Because of the lack of guardrails or shoulders, closing is partially for safety reasons. The road was not designed to be an all-season road when built in the 1930s.

Typically the road reopens during the last week in May, but can fluctuate due to the weather’s unpredictability. This year Trail Ridge Road did not open until June 4. 

Officials also announced the closure of Old Fall River Road for the season, but cyclists and leashed pets are also allowed until Nov. 30.