When our first national parks were established more than 110 years ago, automobiles were not allowed inside park boundaries. As thousands of cars began rolling off the assembly lines in the early 20th century, park managers faced a critical question: Should cars be allowed in?

Even before the onset of automobile tourism began, conservation pioneers like John Muir knew the car would change the National Park experience. As Muir prophetically wrote, “All signs indicate automobile victory, and doubtless, under certain precautionary restrictions, these useful, progressive, blunt-nosed mechanical beetles will hereafter be allowed to puff their way through all the parks and mingle their gas-breath with the breath of the pines and waterfalls.”

Now, even as roads have allowed millions of people access stunning landscapes and natural experiences, national parks are often stressed by the number of vehicles attempting to enter areas set aside to be, “preserved unimpaired … for the enjoyment, education, and inspiration of this and future generations.”

Parking lots are overwhelmed. Visitors experience is degraded from gridlock in the middle of wild canyons. People desperate for a parking spot break rules and harm delicate plants and soils.

Perhaps nowhere else in the country is this more evident than in Utah’s national parks. Zion National Park turned to a shuttle system nearly 20 years ago, and Arches National Park is currently considering traffic management options which include a reservation system for entry to the park.

Research into the effects of automobiles in national parks has clearly shown that, when not managed properly through appropriate infrastructure (i.e., adequate roads and trails) or management approaches (i.e., restrictions on use in certain areas or during certain times), vehicles can have negative impacts on wildlife, vegetation, water quality, soils and the visitor experience.

A century after automobiles were allowed into national parks, the American public faces a similar decision: Should we allow street-legal off-highway vehicles (OHVs) into parks? The National Park Service’s acting regional director ordered national parks within Utah to align their regulations with state law, allowing street-legal OHVs on designated park roads by Nov. 1.

This decision leaves many unanswered questions. How will this impact the ecological quality of our parks? How will this impact the quality of outdoor recreation opportunities offered within our parks? Will this compound the already critical traffic management issues the agency is trying to deal with within our parks? Will this impact nearby communities like Moab and Springdale who deal with many of the same congestion issues on their roadways? We currently don’t know.

Since the inception of the national parks, we have come a long way. Science is now supposed to play a role in making decisions about “America’s Best Idea.” Using science to inform park management, we can determine much more than if any impact will occur (because impacts occur with any amount and type of use), we can determine how much impact is acceptable. How much ecological degradation is acceptable? How much noise pollution is OK before visitors can’t experience solitude? How much traffic congestion are local communities willing to accept?

We currently don’t know. But we can find out. Using science, we can better understand how to make decisions about when, where, and how much OHV use is acceptable in our national parks.

As Americans, we have the right to provide input into how our public lands are managed. We also have the right to demand that public land management decisions be guided by the best available science. Precaution is needed before decisions are made that can change how we experience the pristine landscapes of our national parks forever.

From left: Utah State University professors Jordan W. Smith, Chris Monz, Zach Miller, Mark Brunson

Jordan W. Smith, Ph.D. is the director of the Institute of Outdoor Recreation and Tourism and an assistant professor at Utah State University.

Chris Monz, Ph.D. is a professor of recreation ecology and management at Utah State University.

Zach Miller, Ph.D. is an assistant professor of wildlife and society at Utah State University.

Mark Brunson, Ph.D. is a professor at Utah State University.