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Pavement Markings: Why Those Little White Lines Are a Big Deal

I recently purchased a remarkable gadget: a pavement-marking quality detector system. As I drive, it informs me whether the lane markings are in good shape—green for yes, orange for no. So, what’s the big deal? I can see where the edge of the road is. Do I really need markings to tell me to stay in my lane? Does it really matter if those markings are faded, or even there?

Well, that pavement-marking detector is actually the lane departure warning system in my new car. A camera mounted in front of the rearview mirror watches the road, trying to find traffic lane markings. When it can, it activates the safety system that gently steers me back into my lane, in the event I hypothetically dropped candy in my lap.

It’s constantly assessing the conditions, and I’ve found myself much more invested in road markings than ever before, often disgusted at long orange stretches of road that force me to give driving my full attention. (I’m joking, always give the road your undivided attention.)

Over the last century, pavement markings have undoubtedly prevented many accidents and saved countless lives. I certainly get a little twitchy when driving on a freshly resurfaced road that hasn’t yet been painted. It feels a little like Kramer’s wide-highway lanes from Seinfeld, but with more oncoming traffic.

Of course, pavement markings have always been about safety. The first emergence of painted center lines on modern roadways was in the 1910s, but it wasn’t until the 1930s that standards were first published. There are some accounts of ancient roads with white rocks along the center line, but there is some dispute as to whether this was functional or decorative.

I often hear people dismissing assistive technologies in modern vehicles, arguing that they encourage distracted driving and decrease road safety. Luckily, the data paints a different picture. A 2016 study analyzing crash data found the following:

Lane departure warning lowers rates of single-vehicle, sideswipe and head-on crashes of all severities by 11 percent and lowers the rates of injury crashes of the same types by 21 percent.

That means that if all passenger vehicles had been equipped with lane departure warning, nearly 85,000 police-reported crashes and more than 55,000 injuries would have been prevented in 2015 (IIHS HLDI, 2017).

Wow. Let’s not forget about driving in the dark. Lane departure systems also work at night, relying on a minimum level of retroreflectivity. According to the Federal Highway Administration’s (FHWA) proposed amendments to the Manual on Uniform Traffic Control Devices section on Maintaining Pavement Marking Retroreflectivity:

The need for improved pavement markings has become more apparent in relation to advanced driver assistance systems (ADAS) in vehicles. … Automakers, suppliers, and research institutes have indicated in interviews that maintenance of pavement markings will be necessary to support vehicle automation.

Michael J. Robinson of General Motors testified before the House Committee on Transportation and Infrastructure Subcommittee on Highway and Transit that, "One of the key highway needs is to provide—at a minimum—clearly marked lanes and shoulders" (FHA, 2017).

The FHWA clearly understands the traditional safety implications of clear pavement markings and are now giving clarified guidance on appropriate standards recognizing their increasing importance for automated vehicle safety systems.

Pavement markings might not be at the top of your local government’s priority maintenance list. Perhaps they degrade to vanishing point before you mobilize to reapply. However, if you start to combine the safety benefits along with the ever-increasing numbers of vehicle systems that use markings to make everyone on the road a little bit safer—if you can significantly cut the number of fatalities on your roads just by better maintaining your pavement markings—doesn’t that make those little white lines a little more interesting?

If you haven’t already, now is the time to get a solid inventory of your pavement markings and their condition. Then, start formulating and budgeting for a realistic replacement plan following the FHWA guidelines. It's hard to ignore the numbers especially when people’s lives are at risk. Which is why I feel a little bit safer and a lot happier when that little symbol turns green on my dash.

As vehicle automation advances, we’ll need to find a way to safely self-drive when road markings are missing or obscured. But, in the intervening years and as more vehicles adopt safety features like lane departure warning, how many accidents can be prevented? How many lives can be saved by increased application and maintenance of clear lane markings? Based on the current statistics, a lot.