Word on the Street: More lanes often mean more traffic, not less

Every driver who has ever been stuck in traffic has dreamed of having just one more lane available to allow cars to move around the bottleneck.  

But that dream is an elusive one, and building more lanes often results in the same traffic nightmare. The reason is that travelers who have been avoiding the congestion by not taking discretionary trips, traveling at a different time, or taking a bus or train instead of driving are inclined to drive more when new capacity is available. At the same time, new commuters may be brought into the corridor as highway expansion spurs development in new areas. As a result, adding lanes often only provides temporary relief to traffic congestion due to the additional traffic enticed by the promise of easier travel, a phenomenon known as “induced demand”.

“The bottom line is that we can’t just build our way out of congestion. When you try to do that, what we see over and over is that you spend millions of dollars to end up right back where you started,” said Trip Pollard, leader of SELC’s Land & Communities Program.

Those millions of dollars spent don’t even include the additional, recurring costs to maintain those new lanes that are now added to a transportation department’s budget. Nor do they account for the often significant environmental and community impacts of the expanded infrastructure and the suburban sprawl that often accompanies it.

Planners and decision-makers need to consider induced demand when assessing alternatives for addressing congestion. The Georgia Department of Transportation, for one, has recognized that so much potential demand exists in metro Atlanta that it cannot build uncongested interstate lanes. 

While every traffic situation is unique, there are a host of options other than expansion that can help open clogged thoroughfares. In Atlanta, the DOT has decided to toll all new interstate lanes in an effort to reduce the demand on those new lanes and ensure that, at the very least, the new tolled lanes function during rush hour for those willing to pay the extra fee.  

Charlottesville’s Route 29 Solutions project illustrates another approach. There, local drivers are the primary cause of congestion along the business-lined Route 29, so the state is upgrading the parallel road network to give those drivers alternatives to using the main highway, as well as better timing traffic lights for those remaining on Route 29.

As the Southeast looks to accommodate the projected growth in the region in coming years, there will be ample opportunity for planners and decision-makers to consider expanding highways or, more wisely, avoiding the pitfalls of induced demand and embracing the many alternative solutions available.  


SELC’s Land and Community Program tackles the growth challenges and decisions shaping the Southeast. This series of posts runs every other week and highlights the broader issues driving this work—transportation and land use developments, alternatives, and progress in our region. Click the links below to read previous posts.

More News

SELC op-ed: Virginians deserved better from senators on electric rates

SELC Senior Attorney Will Cleveland says what every Dominion customer felt as we saw our energy company and our state senators crushing every cha...

Frontier Logistics agrees to $1.2 million settlement in pellet-pollution lawsuit

Frontier Logistics has agreed to pay $1.2 million to settle a lawsuit that alleged the company spilled plastic pellets from its former facility a...

Great hikes from the heart of the Southern Appalachian Mountains

Aside from their boundless beauty and opportunity, one of the most magnificent things about our American national forests is our shared responsib...

Hydrogeologic report warns of pipeline threats to Memphis drinking water source

A hydrogeologic report presented to Memphis Light, Gas and Water (MLGW) warns that the Byhalia crude oil pipeline proposed by Valero Energy Corp....

Landmark clean transportation bills advance in Virginia

Transportation is the largest source of carbon pollution in Virginia, as it is across the South. People drive over 230 million miles every day in...

Tennessee Congressman urges White House to rescind Memphis pipeline permit

Congressman Steve Cohen (TN-09) wrote to President Biden urging that he direct the U.S. Army Corps of Engineers to rescind its recently issued na...

More Stories