They allow for absorption of runoff, recharging aquifers, and naturally filters the water before it reaches ocean, lake and river outfalls, improving water quality. It reduces the dangers from flooding and the need for huge storm drains and channels. Additionally, it can help with the 'heat island' effect where the heat of the sun is stored in all of the concrete and asphalt of urban areas, thereby trapping the heat and altering the micro-climate of the area.
There are several methods out there from just using a permeable porous concrete type mix if you prefer a solid looking surface, to a brick style where water can run through the cracks, a basic gravel, or just go all the way and create a green live driveway of grass, turf or native plants. The really easy (and somewhat common) way to create a green driveway is to plant an area and provide a solid surface (such as bricks or concrete strips) for the tires only. No matter what style suits you, there is a greener driveway option out there. Professionals are out there who can help you plan and execute your eco friendly driveway, or you can just do it yourself (DIY). Lets start with the variations on what is available in the way of environmentally friendly driveways.