Rohnert Park's ‘Gravity Hill’ Seems To Defy Physics

ROHNERT PARK, CA — In the wilderness of Sonoma County, in the hills between Rohnert Park and Penngrove, a lonely stretch of road seems to defy gravity. Locals say that a car, when placed in neutral at the foot of the uphill grade, will gradually roll up that hill.

That's right. Up the hill. Impossible? Maybe.

Whether you believe the area to be a paranormal place that flies in the face of physics or choose to focus on scientific explanations for the “gravity-defying” hillside, it’s still a must-do, according to Rohnert Park locals.

Lichau Road, one of many 'gravity hills' across the globe, cuts across the rolling hillsides between Penngrove and Rohnert Park 50 miles north of San Francisco. Its description meets every requirement for a true gravity hill illusion such as those identified by physicist Philip Gibb, author of "Elliptic Curves and Hyperdeterminants in Quantum Gravity."

The road rises with the rolling hills, where the level horizon is obscured. Trees, fences, and power lines that normally would provide visual cues for what is up or down-slope are all leaning slightly. According to Gibb, this creates the illusion that explains why cars behave strangely when left to roll.

For drivers who wish to experience the gravity road, there are a few suggestions:

1. Stop the vehicle safely - at the start of the slight uphill grade.
2. Put your car in neutral.
3. Turn on your hazards.
4. Take off the emergency brake.
5. Allow your vehicle to roll “uphill.”

There are no signs to point out where on the road this occurs, but Google Maps has the location pinned. Once you arrive, there is nowhere to pull over on Lichau Road to take in the unnerving science experiment.

“The weird thing about Lichau Road is that if you didn’t know it was a gravity hill already, you wouldn’t expect anything out of the ordinary,” a fan known as Emerson wrote on OnlyInYourState.com. “It looks completely normal.”

Reviewer Sarjeet Singh shared his experience on Google Maps, saying he read about the gravity hill online and decided to check it out with his kids.

“They had a blast!” he said. “I had to drive around a bit and was amazed when I found the place. There is nothing else out here and not a lot of cars.”

Another reviewer says there is nowhere to pull over to assess the situation after you’ve experienced being in a car that’s rolling uphill.

“It was worth going because I’d never been,” Carolyn R. said in her review. “I recommend going at least to check it out, if not to inspire your minds. It’s trippy.”

While the average person is amazed, scientists offer clues as to why this happens. It’s apparently the result of a complex, naturally occurring optical illusion.

The “magnetic anomalies” such as that at Lichau Road and other gravity hills are optical illusions, Gibbs said.

The leaning trees and wonky hillsides with no horizon lines create the illusion. Much of it depends on our ability to determine “which way is up. The steepness of the slope is often underestimated. The landscape creates an optical illusion making a slight downhill look like an uphill slope.”

Though most will wiz past the local phenomenon, Lichau Road remains a fun way for Rohnert Park locals to freak out their friends.

As Gibbs says: “Even when the true cause is understood, it can be difficult to believe.”