But a car? On the trail?
It's now happened twice in a week - both times, captured on camera.
While biking to work Monday, Ben Matthews faced more than ice and snow.
The camera he has attached to his bicycle captured video of headlights in the distance, which made their way right next to him.
"I'm like...that's a car! Certainly not something you expect to see on the Monon," Matthews said.
The car was driving on the pedestrian trail.
Ben thinks the car likely got on the trail just north of 111th Street, near the Community Center.
"In the video, you can see them turning around doing a five point turn around 116th Street, and then they head south with their, that's when you see the headlights get big coming right at me," he explained.
But why?
Ben's baffled.
Signage is quite clear on the road near the Community Center - with yellow flashing lights, a "Monon Greenway" sign and a picture of a pedestrian.
A Carmel-Clay Parks Department spokesperson says there are also cones in the middle of the trail to deter drivers.
During the summer, those cones are replaced with concrete barriers, when freezing isn't an issue for emergency crews who might need to get through the trail.
"This driver, they seemed to realize they made a mistake, so I didn't stop or yell at them or anything, just kind of like hey what the heck, what are you doing? But it should be pretty obvious that it's a pedestrian trail," Matthews said.
But it isn't the first off-road incident in the same spot.
While on a stationary bike in the community center, Alisha Hiatt snapped photos last Tuesday of a silver SUV straddling the center line, driving down the Monon in broad daylight.
The only cars allowed on the trail, by Carmel ordinance, are emergency, city or maintenance vehicles.
Carmel Police say these vehicles from the past week were likely in violation, which could result in a citation or warning.
They say this hasn't happened until recently and are unsure why it is now.
If it happens again, they'd like people to call police and report it right away.
Meanwhile, Ben's just glad no one got hurt.
And the Parks Department has another theory on the drivers' errors.
Perhaps their GPS was set to "Pedestrian" instead of "Car."
That would have sent them onto the trail, if they were headed to the Community Center, thinking the person was walking, not driving a car.