Lane lines that look half white and half black have gotten a typical sight for drivers on newer stretches of concrete highway across the country. Called contrast pavement markings, they’re designed to resolve a typical problem with standard white lines. And no, it isn’t white line fever, also referred to as highway hypnosis. It’s that they wash out on pale pavement, with the white stripes on light concrete almost disappearing on shiny days. By giving the attention something darker to deal with, the black component goes a good distance in fixing that.
Traffic-safety engineers explain it as creating the identical effect you get when a thick white line pops against dark asphalt. The difference is in-built here, with alternating white and black strips (referred to as “lead/lag”) or white lines bordered with a skinny black outline. Agencies have been expanding their use for twenty years, and plenty of now include contrast markings at any time when concrete pavement is installed or rebuilt.
A security improvement with measurable results
While the markings look easy, their impact on safety has turned out to be significant. Even minute improvements in visibility can go a good distance, since about half of all fatal roadway crashes across the nation are lane departure crashes. Research in 2022 from the Illinois Center for Transportation and the Illinois Department of Transportation taking a look at data across six states found that contrast pavement markings reduce total crashes anywhere from 12% to 29%, depending on what number of lanes the highway has. Even when looking only at fatal crashes, there have been reductions of seven% to 19%.
A 2024 study using Indiana data saw even higher gains: 42% fewer crashes on roads with bordered centerlines and 44% fewer with lead/lag patterns combined with bordered edge lines. These studies controlled for lane width (wide lanes are known to be more dangerous than narrow ones), variety of lanes, and roadway design, and removed crashes tied to extreme weather. Even property-damage-only crashes measurably improved.
Why these markings will matter much more in the longer term
Nowadays, cars’ driver-assistance systems are increasingly reliant on the cameras onboard to remain in the middle of their lanes, while making us more distracted as drivers. Since modern lane-keeping systems search for the contrast between light and dark pixels, these markings give the cameras a more visible goal to follow. The lines are also laced with glass beads that reflect sunlight or automotive headlights at drivers, further increasing visibility. These do their job even within the rain, because a few of them are barely taller, sitting barely above the surface when the road is roofed in water.
Agencies are also planning ahead. As connected and automatic vehicles turn into more common, pavement markings shall be one among the core pieces of infrastructure those systems rely upon. Federal researchers are studying how sensors read several types of markings and the way to keep them detectable in rain or low sun. Some agencies are even exploring enhanced markings that use magnetic signatures or radio-frequency identification tags to assist vehicles anticipate curves and calculate protected speeds.
This Article First Appeared At www.jalopnik.com
