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Executive Summary
Road Work Ahead
Is Construction Worth the Wait?

The United States is experiencing a boom in road construction as an infusion of new federal dollars reaches the states. In many cases these road projects are designed to ease traffic congestion by widening or otherwise expanding the capacity of existing roads.

But ironically, the construction projects themselves can create significant congestion and delay. Transportation officials rarely consider the impact of these delays when they promote the congestion-relieving benefits of a new road. To see if these delays ultimately result in better commutes for those who regularly use the roads, STPP conducted case studies of road expansion projects now underway around the nation.

We used figures provided by state Departments of Transportation (DOTs) and selected case studies according to the nature of the project, geographical distribution, and availability of data. We studied both large and small projects that expand road capacity by adding travel lanes and modifying interchanges.

Results from these case studies indicate that road expansion projects often deliver scant time savings to people who use the road everyday, while allowing and even stimulating significantly more traffic once the construction project is completed. In many cases driver delays due to construction are so long, and the time savings predicted from the finished project so minor, that it can take years for commuters to break even and begin to make up the time they lost during construction.

For the massive I-15 highway in Salt Lake City, Utah, we found that commuters now using the road won’t break even on the time they wasted during construction until 2010, a full eight years after the project is completed. In Nashville, Tennessee, adding lanes to I-24 is causing delays that current highway users won’t recoup until they have driven the new section for more than two years. That puts the break-even point in 2003. In Trenton, New Jersey, the expansion of Route 29 necessitates a detour that costs the average commuter more than 80 hours a year. The new road will save just about 25 hours a year. The break-even point for motorists using this route will not come until 2012, an incredible ten years after completion. Most alarming is the Springfield Interchange located in Northern Virginia outside of Washington, DC. Unless the Virginia Department of Transportation can remove 2,500 cars from the road every day during construction, the average commuter could waste an astonishing 1,750 hours in traffic during the eight years of construction. Motorists who stick it out hoping to realize some time savings once the project is completed will never recoup the hours lost to the reconstruction project.

The results of this study demonstrate how traditional transportation planning fails to focus on what is most important to citizens: their own commute. Engineers focus on increasing road capacity, which they measure through engineering metrics such as "average daily traffic," (ADT), and "Level of Service," (LOS). Unfortunately, these calculations do not adequately reflect the experience of individual drivers. As a result, road projects that succeed in increasing capacity can fail when it comes to significantly improving individual commutes.

Road construction addresses just one part of the congestion problem. Population growth is often cited as the underlying reason for increasing road capacity. However, in the past 15 years, road building has more than kept up with population growth in metropolitan areas: in fact, the number of miles of roadway per person in those areas has increased by nine percent. But the amount the average person drives has grown much faster than the population, with daily miles traveled increasing two to five percent per year since the 1950s. This increase in driving is in large part a result of sprawling, unplanned development that requires many car trips to meet basic needs.

Road construction may in fact have even fewer benefits than those projected here, because additional highway space can lead to additional traffic. While this study relied on official projections of future traffic from state DOTs, in many cases these predictions do not take into account the increase in driving that the new roads will lead to. This phenomenon, called "induced travel," occurs when road capacity is expanded and drivers flock to the new facility hoping to save time. Also, the new roadways tend to draw people who would otherwise avoid congested conditions or take alternative modes to their destinations. In the long run, this encourages additional development nearby, and that leads to even more traffic. Using a conservative Federal Highway Administration estimate of the impact of induced travel, an STPP analysis found that by the year 2011, a mere decade after construction is completed, average rush-hour speed on I-15 in Salt Lake County could drop to 45 mph. This is lower than the average in 1996, before construction began.

These case studies indicate that while construction projects are often billed as relieving congestion for residents and workers, what they may ultimately do is encourage more traffic. Current highway users get little benefit.

Recommendations:

We recommend that:

1. Transportation officials tell citizens how their commute will be affected by road building plans. Investments in road expansion projects should not be made until transportation officials consider the effect of construction delays and induced travel.
   
2. State and local transportation officials place a high priority on reducing delays caused by road construction, by streamlining construction processes and making transit service convenient.
   
3. Transportation officials find ways to provide congestion relief without inflicting the increased congestion that results from construction projects. Among the many techniques available are providing better transportation alternatives, allowing flexible work hours, and clearing accidents quickly.