Drivers on Interstate 5 in northern San Diego County have been noticing something unusual: bright orange lane stripes painted alongside the standard white markings. These lines are part of a Caltrans construction-zone safety pilot, and new data shows the experiment is doing exactly what officials hoped—making drivers more alert and more cautious.
Drivers Slow Down and Pay Attention: Even Without Knowing the Meaning
According to Caltrans, early test results from the Build North County Corridor Project are overwhelmingly positive.
“Survey data shows that 83.18% of road users felt increased awareness of being in a construction zone after encountering the orange striping,” said Caltrans Public Affairs Manager Steve Welborn.
The survey also revealed:
- 72% of drivers slowed down when they saw the orange contrast lines
- Nearly 75% said the markings were easier to see at night
This is especially notable because many drivers still don’t know what the orange lines officially signify—yet the color alone conveys “construction zone,” prompting safer behavior.
For federal lane-color standards, refer to the U.S. Department of Transportation.
Why Orange Works: A Visual Cue Drivers Can’t Ignore
American motorists are used to white and yellow pavement markings—currently the only two colors formally approved by federal regulations. But orange has long been associated with construction zones, signs, and safety equipment.
Its rarity makes it stand out, providing an extra layer of caution for drivers and encouraging them to:
- Slow down
- Stay more focused
- Watch for workers and narrowed lanes
Orange stripes also help with a familiar problem: when old lane markings haven’t been fully removed, making it confusing for both drivers and driver-assistance systems. The bright orange lines cut through that confusion with a clear message:
“This is the lane to follow — you’re in a construction zone.”
Other States Have Tried Orange — But California’s Version Is Smarter
California isn’t the first state to test orange lane markings:
- Laurel County, Kentucky painted orange directly over white and yellow lines in 2019. Crashes rose slightly, but injuries dropped significantly.
- Milwaukee, Wisconsin used orange to improve visibility on snow-covered roads. It worked well during the day, but failed at dusk and night, making the lines nearly invisible.
Those lessons likely shaped California’s approach. Instead of replacing the white lines, Caltrans uses orange AND white together, combining contrast and familiarity.
On I-5, two different test patterns are being used:
- Southbound: an orange stripe painted just ahead of each white stripe
- Northbound: two orange stripes sandwiching the white stripe — nicknamed the “creamsicle Oreo” pattern
This design ensures visibility in bright sun, at night, and across a variety of road surfaces.
A Possible Statewide Rollout Ahead
The four-mile segment of Interstate 5 near San Diego is currently the only location using the orange-and-white combination. But with positive survey feedback and real-world results, Caltrans may expand the program statewide.
California has previously used black-and-white contrast striping on concrete freeways to improve visibility, so an orange-and-white combination is a natural evolution.
If the trial continues to show strong safety improvements, drivers across California could soon see more of these attention-grabbing stripes in active construction zones.
