Although most modern roads do tend to use petroleum products, the asphalt is actually remarkably sustainable as almost all of it is recycled: http://www.asphalt

Although most modern roads do tend to use petroleum products, the asphalt is actually remarkably sustainable as almost all of it is recycled: http://www.asphaltpavement.org/recycling http://www.asphaltpavement.org/recycling. It seems like it would be tough to move to another type of material that would actually be more environmentally friendly after considering all the extra maintenance required for a less durable but more environmentally friendly construction. As others have mentioned, it seems like the long term solution is to move to a less car-dependent society.