What does the white road marking with sawtooth mean?

[LeAlaina]

Road markings with sawtooth patterns on solid lines are called variable direction lanes. It means that after entering this lane, there are multiple directions for traffic flow, that is, the direction of the lane can be changed at any time according to traffic conditions, and drivers need to follow the corresponding lane traffic lights or road signs. The following is an introduction about the markings: 1. Design purpose: This marking is designed to alleviate traffic congestion during peak hours by diverting vehicles and improving traffic flow. 2. Design location: Sawtooth road markings are flexible and different from ordinary lane markings. Such lanes are usually set up on roads with complex traffic conditions.

[StIker]

I often see those white lines with small triangular serrations on the road, which experienced drivers call 'rumble strips.' They are mainly laid out a few hundred meters before highway toll booth gates or in areas requiring speed reduction like sharp curves and steep downhill sections. The principle is quite interesting—while the wheels don’t actually vibrate when rolling over them, the dense serrations create an optical illusion that makes drivers perceive the road as vibrating, prompting them to instinctively hit the brakes. Last week, while dropping my child off at school, I encountered these lines near a toll booth, and the car navigation simultaneously announced, 'Toll booth ahead, please slow down.' This dual-safety design is commendable. Remember, when you see these white lines, don’t accelerate—just obediently slow down below 60 km/h for safety.

[VanChase]

My driving instructor told me that the white zigzag lines are new national standard deceleration markings, usually painted in particularly hazardous road sections. I've noticed they always appear in clusters, ranging from about 50 to 200 meters in length. They reflect well in sunny conditions, and at night the zigzag reflections become especially glaring under headlights. The day before yesterday on the ring expressway, I encountered an upgraded version - the lines were mixed with red and blue reflective particles. Driving over them during heavy rain felt like crushing colored broken glass, creating such a striking visual effect that my speed immediately dropped to 40 km/h. My advice to new drivers: don't panic when encountering these markings, just ease off the accelerator and apply gentle braking.

[LeKingston]

Foreman Wang from the maintenance team mentioned that the serrated markings are painted with special thermoplastic marking paint, which is 30% more expensive than regular lines but offers better reflectivity. During construction, a marking machine with serrated templates must be used, with each serration spaced precisely 15 cm apart. These lines have a shorter lifespan compared to standard markings and require repainting every six months on high-traffic highways. They are most commonly used at bridge joints, as sudden braking can easily lead to rear-end collisions. During the last maintenance check, tests showed that downhill sections with serrated lines reduced accident rates by 40%.

[OAlessandra]

While driving in Germany, I noticed their sawtooth road markings are more exaggerated, covering entire lanes like piano keys. In China, they are relatively restrained, usually only painted at the center divider. Traffic regulations mention that speeding over these markings results in penalty points, as they often come with mobile speed cameras. Once on a mountain road, I saw a clever setup: sawtooth markings at the crest of a hill, followed by three sets of transverse rumble strips, and finally a speed limit sign—a triple whammy for slowing down. Nowadays, navigation apps can also recognize these markings and provide early warnings.

[VanCharlotte]

The traffic design manual clearly states that zigzag lines are classified as longitudinal deceleration markings, with the technical term being 'longitudinal deceleration markings for carriageways.' An engineer friend mentioned that the key parameter is the line segment repetition frequency of 8-10Hz, which precisely triggers the human eye's motion sensitivity. Actual tests show that when driving at 60 km/h, viewing these zigzag lines subjectively increases the perception of speed by 15%. Recently, an upgraded version with raised reflective studs has been spotted, which is extremely eye-catching at night due to its reflectivity. Remember the important principle: the denser the zigzag lines, the stricter the speed limit requirements—don't push your luck and try to speed through them.