Is this freeway stat per lane-mile? Rail often has 2 sets of tracks along a corridor, or at most 4. Roads have a lot more.

I'm guessing even a busy/congested freeway has a greater throughput per lane than transit; even with automobiles with only 1-2 people in it, vs a train that may have hundreds but pass only every few minutes at most.

One problem with roads is that once you get off the freeway, you need more roads to serve housing and businesses; and the size of those leaf nodes pushes businesses and houses all further apart from each other, necessitating MORE road trips and decreasing walkability.