Did you know that 2% of road transportation emissions actually come from the roads themselves? Two percent may seem like a paltry amount, but when we’re talking about 2% of almost 6 billion metric tonnes (globally, transport accounts for 13% of total global emissions, estimated at 46 billion metric tonnes), that’s nothing to sneeze at!
And, it turns out a number of companies and engineers around the world recognize the need to reduce the environmental impact of roads and are trying to do something about it. Here are three ventures I’ve read about recently:
- A construction firm in the Netherlands is working on a road surface to be made entirely of recycled plastic. The company said the surface should require less maintenance than asphalt, withstand greater temperature extremes, and be laid in a matter of weeks – rather than months.
- Researchers at Washington State University have made a version of asphalt that uses cooking oil in place of crude oil bitumen. Their research has found that cooking oil increases the asphalt’s resistance to cracking. They also believe it could cost much less per tonne, as currently asphalt prices are tied to oil prices (which can fluctuate tremendously).
- A road contractor in Melbourne has been working with a print cartridge recycling company to replace bitumen in asphalt with recycled printer toner and recycled oil. The new mix (TonerPave) is said to be 40% more energy efficient and will save 270kg of CO2emissions per tonne of modified asphalt.
Of course, none of these products has reached the level of large-scale commercial deployment, but I’m intrigued by the many possibilities out there! Road paving may not seem like a sexy topic, but it represents such a significant part of our infrastructure – at least here in the U.S. I imagine driving will always play a major role in U.S. transportation, so it will be important for us to introduce elements of sustainability wherever possible. Plus, if they have the added benefit of being more durable, the U.S. stands to save a large amount of money in the future – a majority of the money allocated to road construction goes toward maintaining and repairing roads, rather than building new roads (in 2011, $21.6 billion out of the $31.8 billion allocated by the Federal Highway Administration was spent on improvement to the road system, rather than new road and bridge projects).
A lot remains to be seen on the viability of these new technologies:
- Are they safe in all road conditions?
- Are they as or more durable than asphalt concrete?
- Will they be price competitive? (The cost of TonerPave is already equal to that of standard asphalt and is expected to decrease further as the product matures.)
- Will the needed materials be available on a large scale? (Bruno Bujoli, director of research at CNRS (Centre National de la Recherche Scientifique), is worried that commercialization of asphalt using cooking oil will negatively impact food stocks. If the pavement must compete with the need for food, the cooking oil will likely become less readily available.)
Additionally, it will be a long road (pun intended and relished) to transition all existing roads to new, more sustainable materials — the U.S. has over 4 million miles of roads after all! But, when you think about it, roads need repair and repaving quite often; when that need arises, why not just repave with a “greener” version?
If you’ve been reading my blog for a little while, you know that when it comes to climate change mitigation, I support an “all-of-the-above” strategy — MEANING we need to embrace multiple new sustainable and renewable technologies in multiple sectors to meet our emissions reduction goals. I think greening the pavement industry is a valuable piece in what is, admittedly, a complicated puzzle.