The ugly concrete slabs that line urban highways might seem like a necessary evil. Without them, anyone living nearby would have to deal with traffic noise that was twice as loud.
In Amsterdam, the government is experimenting with a different way to block out the sound of passing trucks and cars that still cut noise but are less unsightly. Light, renewable bamboo, it turns out, might work as well as tons of concrete–and possibly even better.
After some successful smaller tests, the city has started growing a 20-foot wide, 500-foot long hedge from bamboo along a busy North Holland highway. As the bamboo grows to full size over the next couple of years, they’ll study the noise reduction and decide if bamboo might make sense everywhere.
The idea came from a city engineer. “He was inspired by a noise barrier in the city of Eindhoven made of aluminum pipes,” says vice-governor Elisabeth Post. “It made him think of bamboo ‘pipes’ in nature, and he thought it might be an attractive, green, and cheaper alternative for noise reduction than traditional materials used in noise barriers as concrete or steel.”
Unlike concrete, the plants absorb sound, so they may ultimately make highways quieter. “We think bamboo might make roads more quiet because the sound waves ‘diffuse’ in the bamboo hedge, rather than bouncing back from a traditional massive barrier,” Post says.
While some other plants are able to absorb noise, bamboo is the hardiest and most likely to survive cold winters and all the salt dumped on roads to reduce ice.
Besides looking better than a sprawling concrete wall, bamboo is also cheaper. The city estimates that growing it may cost as much as two times less than using concrete and steel. It’s also better for the environment; concrete has a massive carbon footprint, while bamboo can actually help suck pollution out of the air.
If the test is successful, the new hedges could potentially be used throughout the Netherlands. It isn’t the country’s only experiment with alternatives: Another city is testing transparent, colorful solar barriers that can generate clean power while they block noise.