1. Smoking (is not allowed) (is forbidden) (is prohibited) in this house.
2. Didn't you see the sign? You (may not) (must not) (may be fined if you) drive more than 30 miles (should this be 30 miles per hour?).
3. Playing football (is prohibited) in this park.
I assume you are trying to express the idea of a prohibition. If not, there are many other possibilities for these sentences. (Smoking [is common] in this house, etc.)
I hope this is helpful.
Student or Learner