Drivers along Interstate 5 in northern San Diego County, California (or, as the locals call it, “the 5”) may have noticed a four-mile section with both the standard white lane markings as well as orange ones. This is part of a Caltrans pilot program to help drivers know that they are in a construction zone in an effort to enhance safety for both drivers and construction workers, reports KTLA 5. The results of this ongoing test are starting to come in, and it appears to be successful.
“Recent survey data shows that approximately 83.18% of road users who traveled in the orange striping experienced increased awareness of being in a construction zone,” said Caltrans Public Affairs Manager Steve Welborn.
The survey also found that 72% of drivers slowed down after seeing the contrast striping, and nearly 75% found the lines easier to see at night.
This is despite many drivers not understanding what the non-standard orange lines mean, despite them having been in use in the Build North County Corridor Project since late 2021. They still realized it was something unusual, and orange generally means something construction-related that’s worth slowing down for, which many of them did.
We’re more accustomed to yellow and white lane markings, which are currently the only colors approved by the U.S. Department of Transportation. But construction orange is an eye-catching color whose rarity can help. It’s a constant reminder that you’re in a construction zone, and that you should slow down and pay extra attention. It’s also a great solution for those times when they’ve done an incomplete job removing previous lane markings, leaving you and driver assistance systems wondering exactly which lane markings you’re supposed to follow. The orange lines clearly indicate, “You’re in a construction zone, and this is where you should go for now.”
A constant reminder
California isn’t the first to experiment with orange stripes in construction zones. According to Road Guy Rob (a great YouTube channel if you’re an infrastructure nerd like me), Laurel County, Kentucky, tried painting orange lines directly over the white and yellow ones in 2019. Although the number of crashes increased slightly, the number of injuries was significantly lower. Milwaukee, Wisconsin, tried using orange lane markings so they could be seen better than white ones on snow and salt-covered roads. This worked well during the day, but the lines were practically invisible at sunset and at night. This may also explain the slight increase in overall crashes that Laurel County experienced.
This likely informed California’s decision to use both orange and white lines, which solves this problem. I’ve seen California use black and white lane markings on concrete freeways. The concrete is light in color, and the white lines, alone, can be hard to see at times, especially in Southern California’s frequent bright sunlight. The black contrast stands out clearly in these areas, making the lanes more visible. A similar orange and white combination isn’t too much of a stretch from what drivers should already be used to.
Caltrans is testing two versions of these lane markings. On the southbound side of I-5, it is using an orange stripe painted in front of the standard white stripe. On the northbound side, it uses two orange stripes sandwiching the normal white stripe, like a creamsicle Oreo. The four-mile stretch of I-5 near San Diego is currently the only place these lines are in use, but the successful trial could mean they’ll start appearing elsewhere in the state.
