Lisbon is banning through-traffic from its city center for a three-month trial period starting April 26. Beyond the center, a larger zone will bar access to most vehicles over 3.5 metric tons — including tourist buses but excluding public transit — between 8 a.m. and 8 p.m. Cars trying to cross town will instead be directed to a semi-circular ring of major roads just beyond downtown, which will act as a de facto beltway. Central Lisbon is undergoing substantial major construction this summer, including a metro extension that will create two new stations, installation of new storm drains to prevent flooding along the city's waterfront, street resurfacing and work on the sewers. If the ban becomes more permanent, it could help Lisbon become carbon neutral by 2030. Lisbon is one of 122 EU cities that have pledged to achieve this goal.