The federal highway program. Highways are heavily, heavily subsidized by state and federal dollars. That's why their true cost isn't born on drivers, and it's something that greatly exacerbates the problem of urban planning the U.S that leads to vast sprawl, urban decay, hell for walkers/bikers and environmental degredation. If all highways were toll roads, most would cease to exist and our cities would become denser, doubly so if all those highway dollars were diverted to public transit.
These aren't contradictory if you look where most of those state and federal dollars come from (i.e. fuel taxes, which is borne by the driver). Mass transit more fits the description of transportation subsidized by non-users.
Not sure they are uniquely Houston, and definitely not their explicit fault, but I'd say the issue is (obviously) large concentrations of people going to the same area. The DFW metroplex has some traffic issues like any metros, but not to the same extent as e.g. Houston despite being a larger metro (but smaller city). And that's the point. Were Houston's employers to fan out even more than they already do, you might see the suburb-to-suburb commutes that many other sprawls enjoy. Maybe there are plenty of people that live in Katy and work in the Woodlands or vice-versa. Not having to ever even enter the city on a regular basis is very welcoming to those who hate traffic.
This is not completely true. In some cases interstates are 80/20 federal/state funded, in others its 50/50. Not sure of any states where it is 100% federal funding of interstates.
Here's some questions we argue:
1. Where's the money coming from? We see massive Houston mega-projects, huge new freeways built on top of massive existent ones. Yet there's no gas tax, no state income tax, and I don't remember there even being a city income tax (that was several years ago that I worked here though). So who's paying for the new freeways?
2. Why do cars clump at exits? Why do Houstonians sometimes spend 15+minutes at a total standstill waiting to exit? Is it because of line cutters (culture of driving)? Is it because of people reacting violently to line cutters (culture of driving)? Is it because of poor design? Is it as the Houston Chronicle has argued and due to feeder roads, a feature that doesn't exist outside of Houston/Dallas (and thus is a strong contender)? Is it simply because the population is massive and driving is the only viable option to get around, and thus the roads are always clogged? Is it actually an issue in San Francisco, and we simply don't notice because we drive motorcycles (unlikely, but I will pay extra attention when we return)?
3. Why the fuck did i-45, in the middle of a 50 year construction project, suddenly swap out freeway-going-under-bridge design in the Clear Lake area for freeway-is-a-bridge design? Now it's terrifying to drive the speed limit over those bridges because you might smash at 65mph into a half-mile exit-clump line.