As the mercury rose late morning Wednesday on an unseasonably mild December day, so, too, did the traffic on Mark Sather Trail, a popular public path with sweeping views of White Bear Lake.

Dog walkers, solo walkers, power walkers, runners, the occasional bicyclist — all made their way at various speeds in the warming sunshine.

On this day, in the age of COVID-19, what they were doing wasn't as interesting as to how they were doing it. How did people comply with social distancing guidelines when they encountered one another on the trail, recommendations that call for a buffer of 6 feet or more?

University of Minnesota researchers are leading a national study and have been keeping tabs on and off since spring. Some of what they find could inform trail management and planning in years to come. Teams of observers are documenting compliance on public paths like the Sather Trail as millions of Americans seek routine and refuge during the pandemic.

Researchers have seen more than 10,000 encounters — in which trail users came together — across 14 trails in six states. In addition to Sather Trail, Minnesota crews have collected data at Lake of the Isles and Wedgewood Park Trail in Mahtomedi. Some takaways to date about trail users' behavior:

• More than half of trail users didn't allow enough physical distance between themselves and other parties.

• In about two-thirds of the encounters, at least one group moved to keep a safe distance.

• The university researcher who is spearheading the study said people have been the most compliant on the narrowest and widest paths. Trail users moved off-trail the most on the narrowest paths, said Ingrid Schneider, a professor of forest resources.

"We anticipated this linear relationship that clearly didn't exist."

• Safety to move off-trail and the surface are relevant and can affect whether people comply, too, Schneider said.

Minnesota, of course, has had higher-than-normal traffic on all manner of trails during the pandemic.

For example, state trail use, on places such as Brown's Creek in the metro, Willard Munger in central Minnesota, and Root River in the Driftless Area, has increased about 50% since January, compared with the same period a year ago. Brown's Creek attracts runners, walkers, cyclists, roller-skiers and others in the Stillwater area. One of the newest state trails, it drew 2,500 users on multiple weekend days through the summer.

The national study began March 31 and ran through June in Minnesota and five other states: Illinois, Florida, Texas, Colorado and California. Trail-watchers were out again in late November for several weeks and will continue the research next spring, Schneider said. Trails in Arizona will get added to the study in 2021, too.

A subset of the study focuses on seven paved paths, including the Sather Trail and Wedgewood Park Trail. Both paths stood out for their level of encounters and compliance.

Trail users encountered one another more than 80% of the time on Sather Trail and fewer than 20% on Wedgewood. Additionally, groups kept a safe distance 43% of the time on Sather and 53% of the time on Wedgewood. Their makeup and environment could help explain the results.

Sather Trail is 10 feet wide and connects city parks. Wedgewood is 8 feet wide, less than a mile long, connects neighborhoods, and lies in a park setting. While a narrower trail, Wedgewood Park has grass along both sides. Sather Trail was in the bottom half of compliance. Lake Avenue, a one-way road, runs along on one side of the path and is a main route out of nearby neighborhoods. On Wednesday, when cars weren't present, Sather Trail users were frequently on the road to get distance from others.

The threat of coronavirus has affected the research, too. Trails were selected on their proximity to observers' homes because of stay-at-home restrictions state to state. Researchers most frequently observe from cars parked near the trails. Trail-counting devices have been used, too. (From May 12-June 14, 1,140 users on foot or wheel on average were counted daily on the Sather Trail.)

Already mindful of the benefits of recreation, land managers might use study findings to modify how they manage trail traffic and how they develop new paths post-COVID, Schneider said. They deserve kudos for adapting under the strain of the pandemic, she added.

Trail width, numbers of users, signage, Covid fatigue, stay-at-home orders and other factors all might dictate what's happening on paths, she said, making the study's insights that much more relevant.

"There is not an answer to compliant encounters," Schneider said. "It's complex, and both trail encounters and their compliance vary," she said.

Regardless, regular users on the Sather Trail said Wednesday most of the people they've observed have respected others' space, even if it means stepping into Lake Avenue or the grass just off the trail on the lakeside.

Judy Peters, 78, and Sue Beane, 70, both of White Bear Lake, and a few friends navigated the busy path while getting in their daily 2-mile walk. Normally, they'd be at the area YMCA, but the pandemic has pushed them outdoors to stay active. They are on the path five days a week.

Carina McCall, 55, and Sue Haglund, 63, were on a workout; they use the trail regularly, too. They said a majority of people attempt to socially distance. Whether it's 6 feet is another question.

Regardless of others' behavior, both said getting on the trail has been vital to their well-being.

"It's been a lifesaver," Haglund said.

Bob Timmons • 612-673-7899