Thanks to a surge in U.S. trade with Asia, our country’s 29 Pacific ports play a major role in the American economy. Nearly half of all shipping containers to the United States arrive at those ports, with California’s ports of Long Beach, Los Angeles and Oakland the three largest in the nation. When work at those ports slows down, as it did over much of the past year while contract negotiations with port workers dragged out, it can pack a significant economic punch.

U.S. GDP grew just 2.2% in the final quarter of 2014, and although severe winter weather contributed to that slowdown, economists blame the West Coast port strike as the primary culprit. True, American exports were already slowing because of the strengthening dollar, but the port strike may have shaved as much as 1% off our economic growth in the final months of last year.

Although the strike was hardly crippling, it does underscore how much the United States desperately needs to invest more in its infrastructure. Pacific ports handled more than half of America’s container imports in 2002. By 2013 that share had fallen to 43.5%, as labor disputes and congestion prompted many shippers to switch to ports on the Gulf and Atlantic coasts.

If you’re an Asian shipper moving a container of widgets from Beijing to Chicago, it used to make sense to unload that container at Los Angeles or Long Beach and then ship it by railroad. BNSF Railway’s TransCon Corridor, with more than 4,600 miles of track between Los Angeles and Chicago, could get that container from port to store in a matter of days.

Over the past decade or so, though, the major East Coast railroad Norfolk Southern (NYSE: NSC) invested heavily in its Heartland Corridor, which runs from the Port of Virginia to Chicago. Coal used to be Norfolk Southern’s lifeblood, until its intermodal business of moving containers from ship to truck to train to their final destination took over. And although it takes more days for a ship to travel from the Pacific to the Atlantic, interminable delays on the West Coast make that longer transit time worthwhile.

The Panama Canal expansion project, which should be completed by next year, will also shift more cargo east. By adding a new lane of traffic, the canal’s capacity will double, allowing larger ships to pass through the Isthmus of Panama. The canal, incidentally, also is a faster, more cost-effective route for Pacific-based ships to reach our Gulf Coast and Atlantic ports. In fact, lower fuel costs can actually make it cheaper to ship Asian goods from the East Coast to the Midwest, where most major retailer distributions are.

Also influencing the flow of imports into the United States is their shifting point of origin. When goods came primarily from China, it made perfect sense that they went straight to the West Coast. But with manufacturing shifting from China to countries such as Vietnam and India, ports on the Atlantic coast and the Gulf of Mexico become much more competitive.

Of course, our Pacific ports won’t be shuttered any time soon. Volume growth pretty much guarantees that West Coast ports will stay busy for the foreseeable future, even if traffic shifts east. For that to happen, many East Coast ports would also need to be deeper to accommodate larger ships, and transportation networks would need to be upgraded to handle the additional volume. Those changes are coming, though. That’s why Norfolk Southern spent billions of dollars upgrading its Heartland Corridor and expanding the Port of Savannah and other facilities in recent years.

Consequently, infrastructure investment should remain on your investing radar. Although we won’t invest the $3.6 trillion that the American Society of Civil Engineers recommends spending on infrastructure by 2020, a lot of money will still need to be funneled into roads, bridges, railroads and ports for us to remain competitive. There’s no reason investors shouldn’t piggyback on that spending to beef up their portfolios.