How bad is traffic congestion in the Twin Cities—and how do we know?
By Barb Thoman, Executive Director
With the release of the recommendations by the Governor’s Transportation Finance Advisory Committee and MnDOT’s annual report on Performance Measurement, there is growing discussion about traffic congestion. Is our congestion among the worst or average for our size? And how do we know?
The Texas Transportation Institute (TTI)’s Urban Mobility Report is the most often referenced national report comparing rates of traffic congestion among metro regions. The most recent report ranked Twin Cities highway congestion 16th in the nation, based on an indicator they call the Travel Time Index, which measures the difference in the time it takes to make a trip during peak times (i.e., rush hour) versus the average of all the non-peak times (i.e., the rest of the day).
Our congestion ranking is exactly our ranking in terms of population—16th. As you might expect, larger metro regions have more traffic congestion than smaller regions, unless your economy is weak, as in Detroit, and then your congestion ranking is lower than your population ranking.
So why does MnDOT’s recent Transportation Performance Report say our region has the 7th worst congestion? This is not 7th worst in the nation; it’s 7th of 32 “large” cities. We are in fact the most populous region of the 32 regions classified as Large. And, we don’t typically compare ourselves with Columbus, Memphis, Las Vegas, or the majority of the places in the Large region grouping. Not surprisingly, these smaller regions have a lower level of economic activity and less traffic congestion—making our rate in the group look high.
So, remember: 16th in size, 16th in terms of our congestion ranking and average.
MnDOT defines congestion as speeds below 45 mph. That seems like a pretty high threshold to me (40-45 mph isn't much of an inconvenience). Nevertheless, for 2011, MnDOT reported that only 21 percent of the 379-mile regional highway system is congested during peak periods.
Nearly 80 percent of our highway system averages speeds above 45 mph at peak periods. Twenty-one percent congested in the peak is a slight drop from 2010, when the rate was 21.5 percent congested. The current rate is about the same as 2003 (20.8 percent) and 2007 (20.9 percent).
So remember: nearly 80 percent of traffic during rush hour is going 45 mph or more
So what is not in these national and local reports that might be helpful to know when you want to draw conclusions about traffic congestion?
Our region has a very large regional highway system—8th largest in terms of lane miles per person, according to the Federal Highway Administration. The size of a region’s highway system does not always correlate with its congestion rate. The transit-rich region of Portland, Ore., is a case in point. That region has only 2/3 of the highway lanes miles that we do, and a congestion rate that TTI reports to be only slightly higher than what we experience. So Portland’s much smaller highway system has not translated into terrible traffic congestion, largely because people have a lot of transit (and bike) options for avoiding it.
It’s also important to know how far people are commuting and slowed by congestion. A region might have terrible traffic congestion, but if the region is compact and commutes are shorter, the impact of congestion on individual drivers is less. If we compare our region to Seattle, we see that Seattle’s congestion rate is higher than in the Twin Cities but peak-period commute trips there are much shorter (13 miles roundtrip vs. 21 miles in our region). In addition Seattle offers many more transit options so people have more options for avoiding congestion.
So remember: congestion is as much a factor of how many options you have and how close things are.
As we look to the future of our region and making mobility possible for everyone, including the additional 900,000 people we expect to live here by 2030, let’s remember that we already have a very large highway system that should be kept in good repair. To remain competitive as a region and to offer people options for avoiding congestion, we should finally build out a 21st century transit system—and safe connections by bicycling and walking. Finally, I hope we can begin to refocus our development patterns in a way that reduces the need to drive so far so even if you can’t avoid congestion, you’re not in it for very long.
See TLC’s policy brief that summarizes FHWA data on highway size at http://www.tlcminnesota.org/pdf/Final%20Highway%20lane%20miles%20brief%202008%20data.pdf
See page 68 of CEOs for Cities' "Measuring Urban Transportation Performance" report for estimates of commute length at http://documents.scribd.com.s3.amazonaws.com/docs/8mi393oq0w1huf4e.pdf?t=1333050452