Why do they put grooves in concrete roads?
Jackie de Longmont writes, “What is driving you crazy?” Why do they put grooves in concrete roads like at home on route 66 to Lyon and route 287? Seems like it not only throws cars away but wears out our tires faster. I don’t see it helping with the ice or the heavy rains only make it worse.
The main reason for these Jackie lines is water drainage. Concrete, for all intents and purposes, is a non-porous substance in a thunderstorm, so the thickets help disperse some of the rainwater that is on the road and help it dry faster. Asphalt, or bitumen, is more porous than concrete and has greater water absorption capacity, so there is no need for grooves.
According to a article in USA Today, the concrete lines were first launched as a solution to a problem NASA engineers needed when the space shuttle landed on a wet runway. âSpace shuttle landing requirements have led NASA scientists to conduct extensive research into reducing hydroplaning on runways. They found that carving out grooves in the runways helped drain water from the runway and significantly reduced accidents. Many highways and airports now have grooved pavements. “
I spoke to Leah deRiel, senior project engineer for the City of Miramar Florida, a city that uses a lot of concrete for roads and receives a lot of rain, talks about the efficiency of these lines.
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She tells me that concrete cannot even absorb all the rain produced even by a small thunderstorm. She says road crews are supposed to pour concrete pavement so that there is a climax in the center. This slope allows rainwater to drain off the side of the road. âHowever, while you want positive drainage and that general direction of flow, you don’t really want that kind of water flow, a smooth sheet of water running across the road in front of you. We call it Sheet Flow, and it’s really easy for cars to hydroplan.
deRiel claims that while these longitudinal grooves present a minor obstacle to the easy flow of water from the center of the road to the side of the road, they also make the water turbulent, which helps tire traction in the event rain. âIt’s the same principle with tires and that’s why it is so important to have a good tread. The groves not only channel water, but they help with traction by increasing the force on the remaining area. There is a point at which the water will flow like a slick anyway if you have a high enough volume of water, so there is a point where the groves don’t really help, but they are way better than nothing.
deRiel tells me that the grooves should be cut almost longitudinally to the driving surface. âThere may be a bit of variation in that because the grinder is run by a human operator, but they won’t be an insurmountable obstacle that sucks your vehicle into two lanes of traffic. They are quite small, and anyone driving a motor vehicle should be an active driver, which means paying attention to road conditions, surrounding traffic, weather conditions, etc., and active steering. Winds in a thunderstorm can generate more force on a car than these grooves, and drivers have a responsibility to maintain control of their vehicles at all times. “
Another reason for long lines in concrete, according to deRiel, is to help reduce the impact of pavement joints. This is why the grooves are cut longitudinally rather than transversely. âConcrete pavement is generally poured in 12 ‘x 12’ slabs, depending on the width of your lanes. Concrete is a fragile material. In order to distribute the load evenly, the slabs are poured as close to the square as possible. They are also cast so that the joints are as close to the track lines as possible, to minimize the risk of your tires rolling over a longitudinal joint to your destination. If you’re 5,000 feet of sidewalk, that’s a lot of joints. Imagine pouring all these slabs by hand. What are the chances that they are all at exactly the same altitude? Not a snowball chance in Miami. If you look at them from the pavement surface, you will likely be able to see a difference in elevation between two adjacent slabs. Get in a car and drive it, you will be able to feel the difference in elevation … on every … single slab. Cars don’t like bumps, drivers don’t like bumps, passengers don’t like bumps, and maintenance workers don’t like bumps either because bumps in the pavement generate heavy loads. ‘impact. Cars take off from one slab to crash into the generally unsupported edge of the next slab. This causes the slabs to crack, usually near the joints, which is a maintenance nightmare. Keep in mind that water drains and can wash away some of the foundation soil under these slabs, especially at the joints! So how do you solve this nasty little problem? You grind the top 1/4 “of the concrete using a machine, so that all the slabs line up.
As for the bumps affecting the life of your tires, deRiel tells me, âEvery driving surface has a texture. Even âsmoothâ driving surfaces have voids / grooves / irregularities when you look at them closely. For example, a freshly paved asphalt road usually has small voids that serve the same function as the grooves in concrete, they help with drainage and prevent leaf runoff. Grooves in the asphalt would be terrible from a material point of view. Asphalt is not as durable as concrete, so grooving in the asphalt would result in a giant, continuous pothole. Do you know which surface has no texture and is about as smooth as it gets? Ice. And while ice won’t wear down your tire, it’s not what you want to drive on because smooth, slippery surfaces are not safe. You want your tires to wear out over time. It is the result of them doing what they are supposed to do, which is to hold the road.
Denver7 traffic anchor Jayson Luber says he’s been covering Denver subway traffic since Ben-Hur was driving a tank. (We believe the actual number is over 25.) He’s obsessed with letting viewers know what’s going on on their record and the best way to avoid issues that arise. Follow him on Facebook, Twitter Where Instagram or listen to his Driving You Crazy podcast on itunes , Stapler , google play Where Podbean.