That's about 20 mph too fast in some of the most remote landscapes this two-lane road crosses. New Mexico 371, one of three north-south corridors through San Juan County, is next on the state's list for improvements, but it may be another year before those upgrades are complete.
Driving the speed limit on parts of the highway can be an accident waiting to happen, said LoRenzo Bates, Navajo Nation Council delegate representing six chapters in San Juan County, including two that border New Mexico 371.
Bates drives a stretch of the highway at least three times per week to attend meetings in the Window Rock, Ariz., capital of the Navajo Nation.
"You're avoiding the potholes, always looking for the bumps, the swells," he said of the road. "When it's dark, you have to anticipate where those swells are. You have to know when they're coming up."
Like its sister north-south highways in San Juan County U.S. 491 and U.S. 550 New Mexico 371 cuts through Navajo Nation land. New Mexico 371, however, is more isolated than the other two highways, with fewer places to stop for fuel or pull over for a rest. It also is much narrower.
The two-lane highway, paved in the early 1980s, is the most direct route from Farmington to I-40. It also joins the tri-city area and some of the biggest Navajo communities in San Juan County with the Bisti Wilderness Area and hundreds of acres of Navajo ranch land, including Navajo Agricultural Products Industry.
The paved highway, which replaced a dirt road three decades ago, was built on top of blue shale, said Dave Keck, director of San Juan County's Public Works department. Blue shale causes the pavement to buck and heave with changes in the weather.
"The road is badly in need of repair," Keck said, though the county is not responsible for maintenance of the state highway.
"The road is heaving," he said. "Blue shale is expansive, and when it's deep down, under the road, it can be very hard to deal with. It gets moist and it expands a great deal. It lifts the road up and makes humps."
To a daytime driver, the dips create hazards, especially at the posted speed limit. To a nighttime driver, the road can be a death trap.
Drivers report little police presence on the road. When surrounded by a landscape of rocks and sand, it's easy to pick up speed, Bates said.
"Even when I'm slightly exceeding the speed limit, people will pass me," he said. "There's a tendency to put the hammer down."
Law enforcement presence on the road is difficult because of jurisdictional issues, state police Lt. Robert Eshom said.
"The road is the state's," he said, "but it goes through the reservation. It's hit or miss all the way from Farmington to Crownpoint on whose jurisdiction it is."
The highway, much like U.S. 550, goes through a checkerboard area, where land is under different ownership and different legal jurisdictions. Navajo police patrol the road, as do state and county officers.
The state in recent years has addressed issues from paving to drunken driving on the other two north-south highways through San Juan County.
The Department of Transportation is working with the Navajo Nation to finish widening U.S. 491, which cuts across the Nation in the northwest corner of the state. The highway, the former U.S. 666 or the "Highway to Hell," until recently was two lanes and the site of multiple head-on collisions per year, many caused by drunken driving.
State police earlier this year pledged a stronger presence on U.S. 550, which runs from Bloomfield south to Cuba, on the east side of the county. The highway recently was the scene of several fatal accidents, also caused by drunken driving. State police responded to the rash of highway deaths by producing heavier patrol on that stretch of road.
The state is addressing the condition of New Mexico 371, though improvements may not come for another year, said Mike McEntee, adjutant secretary at New Mexico Department of Transportation.
The department is shifting $7 million into a project that will level the road for 12 miles north of the McKinley County line.
"We're actively pursuing funding to go further north," McEntee said. "The leveling will address the heaving."
The project is expected to go to bid for the project this fall, said David Martinez, assistant district engineer for maintenance in district 5 of the state transportation department. District 5 covers much of San Juan County.
Martinez expects construction to begin in the spring and take between six and eight months to complete.
"It will be done by next fall," he said.
Meanwhile, the department is posting signs along the worst stretches of the road to warn motorists to slow down, McEntee said.
Bates wants to see more of the highway upgraded.
"I wish they'd fix the whole thing," he said of the 100-mile stretch. "They need to address this road continually, not on and off."