Impacts of Climate Change on Transportation: Freight Flow in Gulf Coast

From the Transportation Research Board (TRB) report Potential Impacts of Climate Change on U.S. Transportation, this case study describes the transportation sector’s response to Hurricanes Katrina and Rita. It focuses on the storms’ impact to national-level freight movement, highlighting efforts to reroute traffic in order to avoid long-lasting disruptions. Despite damage to Gulf Coast transportation systems from Hurricanes Katrina and Rita, the region experienced only modest disruptions to freight flow because transportation system redundancies allowed traffic to be rerouted away from impacted areas.

The Gulf Coast is a vital economic region for the United States, home to several of the nation’s most heavily used ports. These ports are important due to the area’s centralized location with respect to the rest of the nation and the high number of transportation connections by pipeline, highway, rail, and river. However, the geography of this region – an expanse of low-lying flat land along the subtropical waters of the Gulf of Mexico – is extremely vulnerable to hurricanes. Both Hurricanes Katrina and Rita severely disrupted transportation systems. Key highway and railway bridges were destroyed. Barge shipping was halted, as were grain exports out of New Orleans, the nation’s largest grain-exporting port. The pipeline network was also shut down, causing shortages of natural gas and petroleum products.

Despite the damage, freight flows were impacted only modestly. Much of this was due to redundancies in the transportation system that allowed traffic to be diverted away from damaged areas. For example, trucks were diverted from a collapsed bridge on highway I-10 over Lake Pontchartrain to highway I-12, which parallels I-10 farther north of the Gulf Coast. By utilizing several north-south highways that connect the Gulf Coast with major inland transportation hubs, commercial freight movement was almost fully restored within days.

Because the Gulf Coast has a mature transportation system with sufficient alternative routes, disruptions to commerce were minimized during Hurricanes Katrina and Rita. The study finds that most of the delays to restoring transportation services occurred because of a lack of electrical power and personnel. To increase the resilience of Gulf Coast transportation infrastructure, the case study recommends enhancing  the redundancy of power and communications systems.

In addition, the modest impact to freight movement occurred because the path of the storms spared major rail infrastructure, and because the storms struck before the peak season for corn and soybean exports. With this in mind, the study indicates that the Gulf Coast’s transportation system is still significantly vulnerable to hurricanes, especially given the uncertainty of future storm patterns resulting from climate change.

Finally, the case study notes plans to relocate and redesign port and rail facilities to improve resilience for future hurricanes. Additionally, most of the damaged major river and bay bridges will be rebuilt at higher elevations to accommodate forecast surge levels, following FHWA’s recommended use of a 100-year design frequency for Interstates, major structures, and critical bridges. FHWA also recommended design guidelines consider the combination of wave and surge effects, which FHWA has addressed in Hydraulic Engineering Circular (HEC) 25, Volume 2, released in October 2014.

 

This Adaptation Clearinghouse entry was prepared with support  from the Federal Highway Administration. This entry was last updated on October 31, 2015.
 

Publication Date: 2008

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