Roads in San Antonio... questions

[huckster]

As a road builder for thirty five years, all over the country, I can answer your questions.
I am a grader-finish grade-operator.
The subsoils of San Antonio are notoriously unstable. A lot of clay mixtures of different varieties.
All absorb water and then EXPAND and displace all soils above, even road surfaces , thus the uneven
surfaces sometimes even severe changes in grade over short distances causing cars ability to go airborne like on Marbach road. I have seen subdivision streets in San antonio heave and crack
after only a years time. Subdivisions get far less gravel and pavement thickness .It is not the fault of the operators or even the contractor, it is the composition of the soils.
Where the road is built on sandy subsoils the road is far more stable as the runoff groundwater
goes right through the pourous sand underneath the roadbed and does not "heave" upward and lift the roadbed up in the air because the sand does not swell when moisture is applied to as clay would.
Notice how nice hill country roads are, they are also not built on clay.
This is why Floridas roads are so nice.
Michigan , located in the great lakes, has a high ground water table and so even in sandy soils
the ground will heave because of ground frost . The earth will freeze to depths of two feet and of course frozen water expands thus once again a "heaving" effect occurs and the road surface
once again is compromised, and ruined. Michigan has far worse roads than Texas has. You should all drive around Detroit once , huge potholes, right in the interstate, expansion joints that never seat back after the spring thaw and leave the surface so uneven that the car jolts with each joint. Small potholes become huge when ice expands them and cannot be repaired except with repaving.
So consider yourselves lucky.
Blademan