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       North Austin resident Jennifer Tull was driving to the Copperfield neighborhood one evening to pick up some free houseplants. She gripped the steering wheel of her Toyota Corolla tighter as the lane markings on the pavement seemed to disappear before her.
       “In a lot of parts of Austin, the lane markings are hard to see at night,” she said on a rainy day in North Austin. “If there’s oncoming traffic, it’s really scary, and you just hope they’re not playing cowards with you. If they have bright headlights on, it’s even worse because you’re going to hit them head-on.”
       Tull wondered why these lines were so hard to see in the dark, so we explored this in the ATXplained project.
       More than half of Austin’s road fatalities occur at night. Crashes often involve vehicles leaving their lanes, so the city works hard to ensure lane markings are clear and visible.
       “We have about 40 technicians who work extremely hard every day,” said Lauren Seida, who oversees signs and markings for the Austin Department of Transportation. “They are stressed and overwhelmed.”
       The city plans to repaint half of its major thoroughfares, or arterials, each year, about 185 miles (290 kilometers). Austin repainted 54 percent of its arterials last fiscal year. Non-arterials are repainted about every four years.
       ”Even if we hired 100 more people and brought all the trucks in the world, there would still be a lot of work. There are too many streets,” Seda said.
       The painting machine sprays lines and then sprays tiny glass beads over the lines, which are like a powder and stick to the paint.
       Each glass bead acts as a small directional mirror, reflecting light from the headlights back into the car. Directional reflection of light is called retroreflection. This is why newly applied road markings glow at night.
       “Instead of reflecting the light back to the source, the water scatters it through refraction,” said Chandra Bhat, an engineer at the University of Texas at Austin’s Transportation Research Center. “Basically, instead of reflecting the light back to the driver, it scatters all over the place, making it harder for the driver to see.”
       Pipes can quickly become coated with dirt and other contaminants splashed up by cars and trucks. The problem is often worse near construction sites and other areas where dirt is more likely to accumulate.
       “The real issue is cost,” said Adam Pike, an engineer who studies road markings at the Texas A&M Transportation Institute. “It’s like a standard water-based paint with glass beads, which is basically a base coat of pavement. It’s the least expensive system out there. Like most things, you get what you pay for.”
       The city currently spends about $6.6 million a year to hire two companies to strip sidewalks and install traffic signs.
       Other materials used for lane markings include what’s called thermoplastic, which is used for crosswalks, arrows and the lettering you see on the street. Cities sometimes use thermoplastic for lane markings, and while thermoplastic lasts longer, it also tends to stain, fade and crack. If a street needs to be closed, the thermoplastic needs to be sanded down, Seda said.
       Raised pavement markers—small reflective squares on the ground—also improve visibility at night, but they can cost several dollars to install.
       3M makes a sidewalk marking tape called Stamark that uses high-tech ceramic beads instead of glass. Stamark lasts for years but costs 10 times more than paint.
       ”If you look at just the initial purchase price, it’s definitely more expensive, but the tape lasts a long time,” said Dan Chen, vice president of 3M’s transportation safety division. “Long-term, it’s about the same cost as putting on cheap paint that lasts six months to a year, sometimes less.”
       Austin is experimenting with a variety of reflective materials, including some 3M products. A pilot project involves using thermoplastic sheeting and 3M ceramic beads as crosswalk and lane markings at several crash-prone intersections. Austin-Travis County EMS has used Stamark materials for years to help emergency vehicles navigate tight spaces.
       Eventually, the federal government could force Austin to use more expensive materials, which would cost millions of dollars in federal funds to pay for.
       The U.S. Department of Transportation is adopting new minimum standards for the reflectivity of road markings for the first time. State and local governments have four years to develop plans to ensure that road markings are bright enough to be used at night.