As each year passes, Southern states are becoming more urban. Cities like San Antonio, Atlanta, New Orleans and Houston are booming with transplants from all over the world, but few are taking serious steps to plan for their long-term growth. If southern cities do not take their own growth seriously, generations of Americans will face the consequences.

Let us use Houston as a case study. The population of Houston has grown so dramatically that it is now the fourth largest city in the US and the largest in the South. Its metropolitan area is the third largest in the country: more than 6.6 million people live in the Houston metropolitan area, and the population is expected to reach 11.1 million by 2040. Despite its size, Houston still has exactly zero zoning laws. This is emblematic of Houston’s generally laissez-faire approach to urban planning.

Houston’s relaxed urban planning is a blessing and a curse. On one hand, it has contributed to Houston’s remarkable economic growth. For eight straight years, Harris County, in which Houston resides, was the fastest growing county in the country. In spite of this growth, Houston has managed to keep rent relatively low, which few American cities have managed. It is also home to more Fortune 500 companies than any city but New York.

But Houston’s lack of planning has serious consequences. Often called “the blob that ate East Texas,” Houston relies on its highways to support millions of commuters every day. Houston’s roads have struggled to keep up with its explosive population growth. Now, the city is plagued by some of the worst traffic in the country. The traffic problem is expected to get even worse with time, which means Houstonians will continue to waste millions of hours every year sitting in traffic.

Even worse, Houston’s hands-off urban planning failed to prepare adequately for extremely heavy rainfall. The city is now prone to flooding, which exacerbated the damage caused by Hurricane Harvey. More than a year after the hurricane, Houston still has not decided how to prepare for future storms, so the city is still defenseless against its next hurricane.

Houston is not alone in this struggle. Atlanta is struggling with similar growing pains, and so are Charlotte, North Carolina; Nashville, Tennessee; Baton Rouge, Louisiana and many other cities throughout the south. There is no simple solution to the rapid growth occurring in the South. Adding zoning laws to Houston may not necessarily be the right next step for the city, but we need to acknowledge the fact that population growth will continue to strain these cities and innovative solutions will be necessary to keep them livable.

It is not all bad news: some steps are being taken to make these cities more accessible. Houston has invested in light rail lines, Dallas is investing in pedestrian-friendly neighborhoods and Birmingham, Alabama is working with the Urban Land Institute to develop long-term growth strategies. It is vital that southern cities build on this growth or the South may be consumed by sprawl from Austin to Charleston.