Complex sentence: The plan also called for making the Cabrillo Bridge one-way, eastbound only, so that people could enter the park via the Cabrillo Bridge but could exit only via Park Boulevard.
Split into simpler sentences: The plan also called for changes in access to the park via the the Cabrillo Bridge. The bridge would become one-way, eastbound only, so that people could enter the park via the Cabrillo Bridge but could exit only via Park Boulevard.