Why Some White Lines On The Road Get Closer Together

Accounting for road stripes and markings when driving is essential to the safety of yourself, your passengers, and those with whom you share the road. That said, it’s not always clear what certain markings indicate. For example, not all drivers might realize that orange stripes on the road in construction zones are meant to increase visibility of road stripes. Similarly, you might come across white lines that get closer together as you travel over them. While these markings aren’t directing you to do anything specific, they are meant to influence your driving if you happen to be speeding.

These types of markings are referred to as speed reduction markings or optical speed bars, and they can take several forms. Sometimes, they consist of small white boxes along the sides of a lane. In other instances, they may appear as horizontal lines that stretch across an entire lane. These are sometimes called transverse markings. In either case, as you drive over them, the distance between these markings will decrease.

Roads have these markings to guard against speeding. As the markings or stripes get closer together, the visual effect may cause a motorist to become increasingly aware of how fast they’re traveling. If they’re traveling too quickly, the speed reduction markings can theoretically make them realize this and they’ll reduce their speed accordingly.

Researchers who’ve studied whether speed reduction markings effectively serve their purpose have arrived at several conclusions. Based on questionnaires, they found that most participants in their study believed that speed reduction markings caused them to slow down when they’re driving quickly.

However, they also discovered that not all of these road markings are created equal. Specifically, the small box types of markings that run along the sides of a lane are less effective at reducing speeding than the transverse markings that cover virtually the entire lane.

That said, the best way to limit speeding may be to deploy multiple strategies. For instance, research has shown that the presence of speed cameras can also make a significant difference in the degree to which motorists exceed the speed limit in a given area. Combined with tactics like speed reduction markings, they may help prevent accidents. In the meantime, if you do come across these markings on the road, don’t ignore them. They could be telling you you’re driving faster than you should.