Although contraflow requires less lead time in other states, Louisiana officials say a shorter time frame isn’t possible. The whole idea is to keep traffic flowing.”But the Louisiana transportation department said the strategy would be too expensive. In Louisiana, shoulders must be at least 8 feet wide to accommodate traffic. In lieu of infrastructure changes, state transportation officials want residents to leave as early as possible. Campbell said she hopes city and state officials continue to think of more ways to help people leave before major hurricanes hit.