School zone conditional restriction

I understand from the wiki that school zones are to be coded as conditional restrictions. The school zone I’m working with has no times of operation posted. Instead the zone is marked by a signal light and a sign that reads “SCHOOL SPEED LIMIT 20 WHEN FLASHING”. There are guidelines for what times the signal should operate, but the guidelines allow for the signal to be active at other times, so the restriction is really “WHEN FLASHING”.

  1. Is the proper way to code this restriction:

maxspeed=30 mph
maxspeed.conditional=20 mph @ (signal flashing)

  1. there is an additional restriction in Texas that outlaws the use of handheld cell phones while driving in school zones. How would I add this additional restriction?