Spilled paint can be hazardous for a bevy of environmental reasons. But when it spatters on an interstate, it can cause dangerous confusion when driving at highway speeds. That scenario recently played out in northeast Florida when a yellow line mysteriously appeared on I-95, the nation’s busiest interstate.

An errant yellow line on I-95 confused motorists

A mysterious yellow line of paint recently appeared on a 20-mile stretch of I-95 south of the San Marco neighborhood in Jacksonville, Florida. News reports showed a thin yellow stripe resembling the lines used on roadways as traffic control markers.

News4Jax reported that the yellow line crossed several lanes — further adding to potential confusion among drivers — and changed in width while continuing for the 20-mile stretch.

The Florida Department of Transportation (FDOT) said the yellow line on I-95 wasn’t “standard issue” for marking roadways. A spokesperson said its presence was a mistake, but it’s unclear who was responsible for its appearance.

Regardless, the yellow line could confuse drivers traversing this stretch of interstate, as photos and video show the errant paint in the middle of a travel lane. Ultimately, the line presented a significant hazard in potentially puzzling motorists and semiautonomous vehicles.

The FDOT announced plans to remove the stripe. As of this writing, the person responsible for the yellow line has not been identified, and no accidents due to the stripe have been reported.

What does a solid yellow line on the road mean?

If the I-95 mysterious paint stripe were blue, purple, or green, there likely would have been far less concern about its presence. Those colors aren’t used to mark U.S. interstates, so drivers could safely assume it was simply spilled paint and thus should be disregarded. However, the I-95 stripe’s color caused confusion because yellow is one of only a few hues used to mark roadways officially.

A solid yellow line on a road can signify a few traffic control measures, but most often, a solid yellow line on a two-way street indicates that passing is prohibited across that line. A solid yellow line might also be used as an edge line along a road, showing where the pavement ends. Solid yellow edge lines can also indicate the roadway’s edge at a narrow or raised median.

Effectively, a solid yellow line designates the edge of a lane of travel, though non-solid yellow lines can dictate a passing zone or the edges of a center turn lane.

Fast facts about I-95, the busiest interstate  

The U.S. Interstate Highway System became a reality when signed into law in 1956, and Interstate 95 was one of the original roadways of the massive public works project. I-95 remains one of the nation’s most-used interstates and has topped the list for the interstate with the most vehicle miles traveled annually.

I-95 is the longest north-south interstate highway, spanning nearly 2,000 miles along the eastern seaboard from Florida to Maine. Over half its length runs through urban areas with daily traffic peaks of about 300,000 vehicles, according to the Federal Highway Administration.