In addition to the previous post, the Texas Department of Transportation (TxDOT) has additional resources about speed limits. This is especially true for state highways:
https://www.txdot.gov/safety/driving-laws/speed-limits.html
On that first page you will see information such as:
Adjust your speed to driving conditions
Observing speed limits means more than driving faster or slower than the posted speed. When you encounter icy roads, drive through rain or fog, and approach heavy traffic or constructions zones, follow these tips:
- Slow down and allow for more distance to stop.
- Look out for flashing beacons warning of intersections.
- Look for pavement markings to guide you.
- Watch for signs alerting you of reduced speed limits ahead.