Is Houston Public Transit Safe?

Going to be visiting Houston in mid-September for a weekend and trying to avoid renting a car. I know Houston isn't an entirely "walkable" city so I've been weighing my options of relying on Uber/Lyft of utilizing the MetroRail system. Main areas I'll be looking to commute from is the Museum district, NRG stadium, and Shell Energy Stadium.

Any insight from locals would be greatly appreciated!