It's nearly impossible for that to not be true. Cars are pretty much the least efficient way to move large numbers of people around.

The upper limit on capacity for even a fairly minor rail project is absolutely insane. In nearly all ways, as utilization goes up the quality of service gets better. Particularly frequency which is the single most important factor most people consider when deciding a transit route - nothing makes the experience of public transportation worse than waiting for the transportation to arrive.

As opposed to driving basically everything about the experience gets worse linearly for every additional vehicle on the infrastructure.