You approach a school bus that has stopped on the opposite side of a four-lane highway. Its red signals are flashing. Do you need to stop here?
Normally, vehicles traveling in either direction must stop for a school bus displaying its red flashing lights or stop arm. However, this rule does not apply if you are on the opposite side of a four-lane highway. [School Buses, 2. Traffic Signs and Rules of the Road, Iowa Driver's Manual]