The trailer for the next season of Girls is out, and if you haven't already clicked over to watch it, you should know it begins with Lena Dunham's character having moved from New York to Iowa City to attend the venerable Iowa Writers' Workshop. "Iowa's incredible," she says while eating grapes. "We should all move here and start the revolution." To which her friend responds: "No one is moving to Iowa, ever."
There might not be a lot of people moving from New York to Iowa City, ever, but there are quite a lot of goods making that trip every year. About $174.4 million worth, to be more precise. We know this because Brookings has built an incredibly useful interactive tool mapping the value of trade commodities between various U.S. cities. (Yes, we did just tie Girls to intercity freight policy. You're welcome.) Here's a look at Iowa City's trading partnerships:
The diagram shows the aggregate value of Iowa City's goods movement on the left ($14.7 billion) and its leading flow routes, combining imports and exports, on the right. In the case of Iowa City, we see several key freight corridors within the state, but we also notice the importance of major cities like Chicago, Minneapolis, New York, Los Angeles, and Dallas. There's even a healthy relationship with foreign countries like China, Canada, and Japan.
The tool can be adjusted by trade sector, too. If you want to know where Iowa City gets most of its grapes, for instance, you can filter the trade results by "agricultural products." You'll find once again that most of the trade partners are within Iowa, in this case, but that major outside metros still contribute a great deal to local agricultural consumption and sales. Los Angeles does about $15 million in these exchanges with Iowa City—equivalent to trading a little more than one Lena Dunham.
In this way, the interactive tool and accompanying report by Adie Tomer and Joseph Kane offer a broader lesson in freight movement and the interconnectivity of America's transportation network. Simply put, a traffic jam on a New York City bridge can impact the cost and availability of snacks for young writers in Iowa City. Here's Tomer and Kane on the "economic interdependence" between metro and non-metro areas (our emphasis):
Both sides require the country’s expansive freight network to operate at peak efficiency, whether initiating supply chains in rural areas or coordinating global value chains from metropolitan areas. It also means that traffic backup at an intermodal center or on a congested highway—the majority of which are in large metropolitan areas—creates costs for traders across the country. In this way, it is critical that rural areas recognize the benefits they receive from freight investments elsewhere.
Several of the statistics collected by Tomer and Kane bear out these big city-small town relationships. In 2010, the largest 10 metro areas facilitated about 80 percent of the country's $20.3 trillion worth of goods movement. Trade with major metros accounts for 84 percent of all non-metropolitan (read: rural) exchange. A small group of huge metros—Chicago, New York, Los Angeles, Houston, and Dallas, at the top of the list—serve as national network centers. And more than 77 percent of all trade goes across state lines. These trends come through more clearly in the below map of the heaviest truck traffic in 2007.
While getting someone a grape requires a harmony of many types of transportation modes, trucks move about two-thirds of all national tonnage. This integrated commercial road network was a primary reason for building the Interstate Highway System—and yet, as Dan Glass reported for our Future of Transportation series, commercial vehicles account for just 9 percent of all highway travel. Cargo firms use logistics to avoid congestion, but passenger traffic in metro areas can't help but overload the road network at times. If you're frustrated by your slow bridge-and-tunnel New York commute, so is a vendor in Iowa City.
Here's Tomer and Kane again (and our emphasis, again):
Critically, it is the federal government's responsibility to reasonably protect local congestion from interfering with interstate commerce. For example, while Des Moines, or even the state of Iowa, will need to examine market-specific freight concerns in greater depth, it is essential that federal policymakers consider how transportation problems in distant hubs like Los Angeles and New York can impact Iowa's industries. Developing a comprehensive national freight strategy across multiple modes and markets is one step that can help prioritize investments.
So let's widen the lens a bit on what all this interconnectivity means. First, it's a reminder that single-occupancy cars take up excessive space on our road network in the service of only themselves, and an argument that they should be charged for that space accordingly—especially during high-traffic times. It's also a counter-argument to elected officials representing remote areas who complain that their state's federal gas taxes are used to pay for roads and transit systems in big cities. We're all in this cheap-consumer-goods thing together.
Last, national freight connectivity is a point in favor of maintaining a strong federal role in highway spending. If infrastructure funding falls primarily to states and local government, as has been the case of late with the declining power of the Highway Trust Fund, then key interstate corridors run the risk of deteriorating—to the detriment of consumers across the country. Tomer and Kane recommend adjusting highway spending formulas to prioritize these vital routes. It seems safe to assume, at least for this season, that Lena Dunham would agree.