So we have all heard about high speed rail, but what about high speed roads? Instead of installing costly and difficult to maintain infrastructure for trains that just go really fast, why don't we improve America's already existent highways and road cars to be able to travel at 150+ mph?

Cars would become even more affordable and with computers and such the engines could easily handle the improved conditions.
Cheaper cars would come with less equipment while more expensive cars would come equipped with predictive merging and radar for detecting the fastest lane to be in.
Mileage would increase because the faster you go the quicker you would get to your destination and the more miles you would pass on the same tank of gas.
It would be a golden age of transportation as everyone would want a car with 400+ horsepower just for leisure. We could put gas turbines in the more high end models and put 2000HP aircraft engines in big rigs. Inject plastic into the tires to make em last longer or something