There’s no single, completely satisfying way of measuring what it is we hate about traffic congestion. In fact, travelers in the D.C. area rarely describe the target of their anger as “traffic congestion.”
Instead, they complain about a traffic light that’s always red when they reach the intersection, about drivers with bad merging habits or about the lack of a more direct route between home and workplace.
All those conditions contribute to congestion and hinder mobility. But they don’t resonate equally with a traveler in Bowie and another in Centreville, let alone with one in Boston or New York.
This creates a difficult task for the researchers trying to quantify the experience of congestion and for the travelers trying to understand what they are experiencing.
The Urban Mobility Report by the Texas Transportation Institute is the study that has become the benchmark for badness. It tries to quantify the problem in several ways. No one measure satisfies all travelers, but the collective impact is telling.
You will see that the D.C. region does very badly overall, even if we’re not always worst in the nation.
Also note that our congestion isn’t worsening as quickly as in the late-20th century, and consider the effect on our transportation planning.
We’re counted among 15 Very Large Urban Areas in the most recent report, which measured mobility and congestion in nearly 500 urban areas based on 2011 data.
Within the large-area group, the worst performers are the D.C. region, Los Angeles, San Francisco, New York and Boston.
Nationwide, many types of congestion recorded in the study peaked around 2005. The report suggests that this is a short-term achievement. The conditions that fuel congestion will return as the economy improves, the report says, and congestion solutions are not being pursued aggressively enough.
Annual Delay Per Auto Commuter: This measures all the delays for commuters who drive in the peak period (6 to 10 a.m. and 3 to 7 p.m.). The institute says it illustrates the effect of congestion per mile as well as the length of each trip.
In 1982, the yearly delay nationwide was measured at 16 hours. It was 39 in 2000 and 43 in 2005 but shrank to 38 by 2010 and has remained there.
The D.C. region ranks first, with 67 hours of delay per year. Los Angeles and San Francisco were tied for second, with 61 hours. The national average among the 15 Very Large Urban Areas studied was 52 hours. Baltimore, considered a Large Urban Area, ranked 23rd, with 41 hours.
Travel Time Index: This measure is a ratio comparing travel time at rush hour with uncongested travel time. An index of 1.30 would indicate that a trip taking 20 minutes when traffic flows freely would take 26 minutes during the peak. The national index had reached 1.23 in 2005 but declined to 1.18 in 2010 and 2011.
The D.C. region ranked fourth in the 2011 data, with an index of 1.32. The Los Angeles region was No. 1, with an index of 1.37. Almost all of our rise on this often-cited index occurred between 1982 and 2000.
Congestion Cost Per Auto Commuter: This calculation measures the value of travel delay and extra fuel consumed in traffic congestion. The D.C. region is No. 1, with an annual congestion cost of $1,398. Among the top 15 urban areas, the average was $1,128. The Los Angeles region was second, at $1,300.
Planning Time Index: This is a new index, so there’s no previous period for comparison. The researchers created the index to measure how much travel time varies from day to day. It’s not just the congestion. It’s the unreliability of congestion and the effect that has on travel planning.
Reducing that annoyance to a formula, the researchers set a fairly high standard: How much extra time commuters should build into their scheduled to be late no more than one workday a month, despite encountering sleet storms, crashes and motorcades.
If the ratio is 3.00, a traveler should allow an hour for an important trip that takes 20 minutes in free-flowing traffic.
The D.C. region is No. 1, with an index of 5.72. The average for the 15 Very Large Urban Areas was 4.08. Los Angeles and New York were second and third. (Don’t use the index as a guide to your own travel preparations. It’s showing us that when travel is disrupted, the impact is severe and widespread.)
At this point, you might be thinking about what a great country this is, where researchers can find employment telling you what you already know about traffic congestion. And yes, the categories covered are broad. But there are enough of them over enough time to give us quite a bit to discuss.
Three decades of indexes and measures point in the same direction: Congestion costs us time and money we could put to better use. Some of us have the luxury of making individual decisions that cut the personal cost. We can live close to work or to a transit station. But what should we do as a region?
The mobility report says that although big urban areas tend to share the same congestion issues, each region needs to find its own “projects, programs and policies that achieve goals, solve problems and capitalize on opportunities.”
And that isn’t a task confined to government transportation agencies. The most effective strategies are ones that combine the efforts of government with those of business and civic leaders, and travelers, the report says.
We haven’t failed to act. The mobility report notes the positive effects nationwide of managing road networks and improving public transit. The decades covered by the studies overlap with the completion of the Metrorail system, the expanded use of high-occupancy vehicle lanes, the creation of high-occupancy toll lanes, the addition of real-time traffic and transit information and more creative use of lane space.
Have we done enough, and do we want to invest more to accelerate improvements?
Yes, we’re the capital of commuter pain, but perhaps that doesn’t hurt as much as it used to, since the pain isn’t increasing as sharply. Are we now willing to endure the costs in time and money that it takes to get around the D.C. region? Have we become comfortable with the things we call congestion?