Skip to content

Posts from the VMT Category

15 Comments

4 Ways Road Builders Game the Numbers to Justify Highways

The people who make the case for highways often present themselves as unbiased technicians, simply providing evidence to an audience subject to irrational bias.

Greenville's Southern Connector, a PPP toll road, was predicted to attract 21,000 vehicles per day. It attracted less than 9,000. Map via Toll Road News

Forecasts said motorists would make 21,000 trips per day on Greenville’s Southern Connector, a public-private toll road. In real life they made fewer than 9,000. Map via Toll Road News

But traffic forecasting is not a neutral, dispassionate exercise. It is subject to all sorts of incentives, beliefs, and assumptions that can skew the results in a particular direction.

Intentionally or not, forecasters frequently exaggerate predicted traffic volumes to make the case for building toll roads, according to industry consultant Robert Bain [PDF]. Bain has catalogued 21 ways in which forecasters manipulate data to make toll road financing look attractive [PDF]. Gaming numbers isn’t limited to toll roads — DOTs do it for taxpayer-funded projects too.

Here are a few tricks Bain says forecasters use on private projects to make highways seem like a good bet to investors:

1. Pick a time frame that suits you

Maybe looking at the last 10 years of traffic doesn’t make that great a case for widening a highway. Why not just pick a different time frame?

To justify its $850 million I-94 expansion project, Wisconsin DOT used traffic data from 1999 through 2010, leaving out two years. But traffic was flat on the road between 2009 and 2012, according to a Wisconsin PIRG analysis, which has pointed out the agency is a notoriously overoptimistic forecaster [PDF].

Read more…

4 Comments

The Feds Aren’t Crowing About the Record Amount of Driving in America

Driving miles are again on the rise after a historically unprecedented dip. Graph: Doug Short

Driving mileage is on the rise again after a historically unprecedented dip. Graph: Doug Short

Gas is cheap again, and cumulatively, Americans are driving a record amount.

Newly released U.S. DOT data shows that through the end of November, Americans drove a cumulative 2.88 trillion miles last year, well above the same period in 2014, indicating that 2015 will set a new national record for driving mileage. Adjusting for population growth, driving is still about 6 percent lower than the peak in 2005, though that metric is also on the rise, reports analyst Doug Short.

On the bright side, at least this time the feds aren’t cheering the news, like they did back in August. Todd Solomon at U.S. DOT’s blog, The Fast Lane, wrote about the drawbacks of more traffic:

Each of those miles is wear and tear on the roadway surface. And when combined, those miles represent a significant challenge to our capacity. And that means traffic congestion. Which means lost time, lost money, and increased greenhouse gas emissions. So, while we appreciate that our roads made possible those 3+ trillion vehicle miles traveled, we aren’t exactly celebrating this new record.

Even if the average American isn’t driving as much today as 10 years ago, too many cities and towns are saddled with infrastructure that leaves people with no good alternative to driving for almost every trip. Without significant changes to transportation and land use policy, traffic isn’t going to decline on its own.

Hat tip: Tony Dutzik

10 Comments

Planning for Less Driving, Not More, Would Lead to Big Savings

masspirg-chart

Chart: MassPIRG

What if, instead of basing policy around the presumption that people will drive more every year, transportation agencies started making decisions to reduce the volume of driving? And what if they succeed?

A new report from the Massachusetts Public Interest Research Group quantifies what would happen in that state if driving rates come in one percentage point lower than the state DOT’s current annual projections. For instance, in a year that the DOT forecasts 0.49 percent growth in driving, MassPIRG hypothesizes a 0.51 percent decrease. MassPIRG estimates that the statewide effect from now until 2030 would add up to about $20 billion in savings and 23 million metric tons of carbon emissions avoided.

The effects grow as the decline compounds over time. In the first year, a one percentage point change in driving rates would save about $167 million in avoided costs of gas, road repairs, and traffic collisions. By 2030, the savings would rise to $2.3 billion per year.

Broken down by category, the state would save about $1.9 billion on road repairs over the 15-year period. Drivers would net $3.8 billion in savings on car repairs and another $7.7 billion on gas purchases. And auto collisions would cost $6.7 billion less to society, as people avoid medical expenses, property damage, and lost wages.

Read more…

8 Comments

Why Creating Meaningful Transportation Change Is So Hard

Cross-posted from City Observatory.

At his blog, The Transport Politic, Yonah Freemark pushed back this week on the idea that we’re seeing a revolution in the way people get around cities and suburbs, largely thanks to new transit-and-bike-friendly Millennials.

In fact, he cites one of City Observatory’s posts as an example of a narrative he doesn’t think is quite right: that despite an uptick in driving as a result of dramatically cheaper gas prices, economic and preference-based fundamentals suggest that we are still in the midst of a historic decline in driving after generations of consistently rising car dependence.

Freemark, who also works at Chicago’s Metropolitan Planning Council, is an excellent commentator on transportation and urban development, and we are all very much on the same page in believing in diverse, inclusive cities whose transportation systems contribute to walkable, integrated, sustainable neighborhoods.

Moreover, the central point of his post is not just correct, but hugely important for all transit advocates and urbanists to understand. As we’ve written, changing preferences are not enough to change transportation behavior, because a person’s behavior heavily depends on their options. Those options, in turn, depend on available transit services and land use patterns.

If the only available public transit is a very slow bus that comes once every 30 minutes—or the only bike route is along a high-speed stroad without a bike lane — it’s likely that even the most car-hating Millennial will get behind the wheel to get to work. Land use is similarly important: if your job isn’t anywhere near a transit station, it’s extremely unlikely you’ll be able to avoid driving, even if you’d really like to. In effect, land use patterns lock in place the mode choice preferences of previous generations and changes in behavior can happen only slowly. We can’t have a transportation revolution without major improvements to transit services and road design, and major reforms to our land use laws.

Read more…

16 Comments

The End of Peak Driving?

Cross-posted from City Observatory

A little over a year ago, a gallon of regular gasoline cost $3.70. Since then, that price has plummeted, and remains more than a dollar cheaper than it was through most of 2014.

Over the same period, there’s been a small but noticeable uptick in driving in the US. After nearly a decade of steady declines in vehicle miles traveled per person, car use has suddenly pushed upwards. Average miles traveled per person, which were 25.7 a year ago, have jumped up to 26.4 in July—the first sustained increase in driving in more than a decade.

Some in the highway community have heralded the growth in driving in recent months as a sign that we need to invest much more in road construction.

The increase isn’t very big, however. In historic terms, Americans are now driving at about the same rate as they were in 2000. It would take nearly a decade of growth at the current rate of expansion just to get back to the level of driving of 2004. But there’s little reason to believe anything like that is in the cards.

Read more…

1 Comment

Without Transit, American Cities Would Take Up 37 Percent More Space

Even if you never set foot on a bus or a train, chances are transit is saving you time and money. The most obvious reason is that transit keeps cars off the road, but the full explanation is both less intuitive and more profound: Transit shrinks distances between destinations, putting everything within closer reach.

A new study published by the Transportation Research Board quantifies the spatial impact of transit in new ways [PDF]. Without transit, the researchers found, American cities would take up 37 percent more space.

Transit-oriented development in Portland's Pearl District. Photo: Smartgrowth.org

Transit-oriented development in Portland’s Pearl District. Photo: Smartgrowth.org

The research team from New York, San Francisco, and Salt Lake City modeled not just how many driving miles are directly averted by people riding transit, but how the availability of transit affects the way we build cities.

By allowing urban areas to be built more compactly, the “land use effect” of transit reduces driving much more than the substitution of car trips with transit trips. Total miles driven in American cities would be 8 percent higher without the land use effect of transit, the researchers concluded, compared to 2 percent higher if you forced everyone who rides transit to drive.

On average, the study found, the “land use effect” of transit is four times greater than the “ridership effect,” or the substitution of car trips with transit trips. But the land use effect of transit varies a great deal across urban areas, the study found. In places like Greenville, South Carolina, it’s responsible for reducing driving 3 percent. In San Francisco and New York City, it’s 18 and 19 percent, respectively.

Read more…

12 Comments

FHWA Gleefully Reports That Driving Is Rising Again

Chart: Doug Short

Chart: Doug Short

After flatlining for nearly a decade, the mileage driven by Americans is rising once again. That means more traffic overwhelming city streets, slowing down buses, and spewing pollutants into the air. But to the Federal Highway Administration, it’s a development to report with barely contained glee.

This June, Americans drove 8.7 billion more miles than last June, according to FHWA, a 3.5 percent increase. Total mileage in 2015 is on pace for a new high — finally “beating the previous record” of 1.5 trillion vehicle miles set 2007, the agency reports, as if the further entrenchment of America’s car-dependence is some sort of achievement.

Low gas prices, population growth, and an expanding economy are three factors nudging traffic back onto an upward trajectory, not to mention a transportation policy regime that remains tilted overwhelmingly toward highway construction.

The recent growth in traffic, however, does not negate lasting signs of a long-term shift away from driving. Economist Doug Short gets into more detail about the nuances in the trends, pointing out that on a per-capita basis, Americans are now driving about as much as we did in 1997.

Read more…

7 Comments

Putting the Recent Uptick in Driving in Perspective

Driving is on its way up again after a decade of stagnation, but it's still not what it was. Graph: Federal Highway Administration

Total driving mileage has risen recently after a decade of stagnation but remains below its 2007 peak. Graph: Federal Highway Administration

With gas prices plummeting and employment figures rising, America’s per capita driving rate increased in 2014 for the first time in nearly a decade. But experts warn driving is far from back to its previous historical pattern.

According to new data from the Federal Highway Administration, total driving mileage climbed 1.7 percent in 2014, higher than the rate of population growth. Gas prices are likely a major factor. In the first half of 2014, driving rose only about 0.8 percent, about the rate of population growth, compared to the same period in 2013. But during the second half of the year, as gas prices dropped substantially, total miles driven shot up 2.5 percent.

Phineas Baxandall, a researcher with the U.S. Public Interest Research Group, says the increase needs to be put in perspective: This doesn’t look like a return to historical driving trends. Prior to about 2005, traffic rose at a fairly steady rate, with some fluctuation around recessions. But this latest increase doesn’t signal a return to that path of constant growth — the kind that has been continually used to justify highway projects.

“This past year saw big increases in employment and a precipitous dip in gasoline prices, yet the rate of increase in driving was still smaller than the normal increases for six decades before 2005,” Baxandall said in a statement. “The total volume of driving in 2014 still fell below 2007 levels, even despite the nation’s larger population.”

Of course, policy makers could also act to spare Americans from the burden of increasing traffic, congestion, and emissions. “The volume of driving could be even lower if public policies in coming years give Americans more choices about whether or not to drive,” Baxandall added. “We hope that this past year’s data does not distract public leaders from the profound changes underway in transportation.”

14 Comments

Americans Are Driving Less, But Road Expansion Is Accelerating

Notice how the new lane miles and miles driven depart in the upper right hand corner of this chart, via FHWA.

Starting around 2005, driving leveled off, but transportation agencies continued to expand roads. Click to enlarge. Chart: FHWA

Americans drive fewer miles today than in 2005, but since that time the nation has built 317,000 lane-miles of new roads — or about 40,000 miles per year. Maybe that helps explain why America’s infrastructure is falling apart.

The new data on road construction comes from the Federal Highway Administration and reached our attention via Tony Dutzik at the Frontier Group, which studies trends in driving. In 2005, Americans drove just above a combined 3 trillion miles. Almost a decade later, in 2013, the last year for which data was available, they were driving about 45 billion less annually — so total driving behavior had declined slightly. Meanwhile, road construction continued as if demand was never higher.

Between 2005 and 2013, states and the federal government poured about $27 billion a year into road expansion. According to FHWA data, road expansion was spread across highways and surface streets fairly uniformly.

That’s actually a faster pace than in previous decades, Dutzik points out. For the whole of the 1990s — when gas was cheap and sprawl development was booming — the country added, on average, about 17,000 lane-miles a year, less than half the current rate.

This is further evidence that America’s “infrastructure crisis” is due in large part to spending choices that favor new construction over maintenance.

13 Comments

The Feds Quietly Acknowledge the Driving Boom Is Over

DOT_forecasts

After years of erroneously predicting rapid growth in driving, the FHWA finally made significant downward revisions to its traffic forecast last year. Graphic: U.S. PIRG/Frontier Group

The Federal Highway Administration has very quietly acknowledged that the driving boom is over.

After many years of aggressively and inaccurately claiming that Americans would likely begin a new era of rapid driving growth, the agency’s more recent forecast finally recognizes that the protracted post-World War II era has given way to a different paradigm.

The new vision of the future suggests that driving per capita will essentially remain flat in the future. The benchmark is important because excessively high estimates of future driving volume get used to justify wasteful spending on new and wider highways. In the face of scarce transportation funds, overestimates of future driving translate into too little attention paid to repairing the roads we already have and too little investment in other modes of travel.

The forecast is a big step forward from the FHWA’s past record of chronically aggressive driving forecasts. Most recently, in February 2014 the U.S. DOT released its 2013 “Conditions and Performance Report” to Congress, which estimated that total vehicle miles (VMT) will increase between 1.36 percent to 1.85 percent each year through 2030. This raised some eyebrows because total annual VMT hasn’t increased by even as much as 1 percent in any year since 2004.

Comparing the 20-year estimates of the “Conditions and Performance Report” issued at the beginning of 2014 to the new 20-year estimates shows the agency has cut its forecasted growth rate by between 24 percent to 44 percent.

Read more…