There are over 175 million cars and trucks in America. Infrastructure is in place for gasoline and diesel. The only readily available viable alternative is compressed natural gas. The infrastructure is in place in eastern US. All service stations have to do is have a tap on a local gas main and install a compressor station to fuel vehicles. Fleets would benefit the most. Natural gas is about $1.85 per gallon equivelant energy to gasoline. That being said, we can also make synthetic diesel from coal. We have about a 200 year supply of natural gas and an 800 year supply of coal.
Why are we using imported oil? It is because of government regulations, restrictions, and meddling. Government restricts drilling. Government uses the Environmental Protection Agency to REGULATE lots of things, even installing gas mains in new subdivisions, every creek crossing, even if we are boring under the creek 15' deep. Mountains of paperwork just to install over 1,000' of gas main in dedicated street and highway right-of-ways. GPS cordinates, maps, description of what we are doing. Discription of trenching, backhoeing, boring methods, clean up methods, how we are going to install silt screens, hay bales, sod, seed, rip-rap, etc, etc. Every single job.
I know it must be a pain for the oil and gas companies to drill, or for the coal companies to dig. Common sense and pragmatism must be used or else we are going to destroy ourselves and our economy. Windmills are bad for the birds. Solar is bad for the animals underneath the solar panels. Coal is bad for producing electricity, natural gas is bad for producing electricity because we might run out. Nuclear is bad because of potential radiation. So what is the most viable alternative fuel for vehicles. Electricity can't take a vehicle but so far, then you have to recharge for 8 hours. This is impractical for cross country trips. The navy is making synthetic jet fuel from seawater, but it requires lots of nuclear power. Algae oil will require lots of greenhouses to be built, taking up potential farmland. It also requires lots of water.