Why widening Interstate 5 in Stockton is not worth the money

Driving along Interstate 5 in Stockton is not a pleasant experience these days: the pavement is littered with potholes, heavy equipment dominates the landscape and shoulder access is restricted by concrete barriers. But many Stocktonians don’t mind the inconvenience because the $262 million lane-widening project signals progress. Likewise, Highway 99 will be upgraded and expanded for a price tag of $250.5 million. To several, these new lanes can’t come fast enough. Local rush hour traffic feels like it has reached Los Angeles or Bay Area grade levels, but once there are more lanes, traffic will disappear!

Sounds like a great plan, too bad it won’t work. Over the long term, these “congestion relief” improvements will not reduce traffic and will most likely make congestion worse for Stocktonians and visitors alike.

How can I make such a brazen statement? Because every other region that tries to build its way out of congestion ends up with more traffic, not less, and there is plenty of data to back that up. At first, this notion may seem counterintuitive: wider freeways means more space for cars which should mean less traffic, right? Unfortunately, this axiom is fatally flawed by two words: induced demand.

The concept of induced demand is simple: when you supply more of a good, more people will consume it. There may be no better example of induced demand than traffic. As more lanes open up on a highway, more people start using those lanes, meaning more people overall are driving, eventually leading to even more congestion. This specific phenomenon is known as “induced traffic.”

Research on induced traffic repeatedly shows that more roads mean more congestion. In 1998, an expansive analysis of over 70 cities by the Surface Transportation Policy Project found that for 90 percent of new urban roadways, it takes only five years for congestion to return.

Is widening I-5 worth the cost?

Is widening I-5 worth the cost?

The study also found that areas spending the most on highway construction actually end up with slightly higher amounts of congestion, fuel costs and travel delays than areas that spend less.

Since 1998, there have been several studies that reinforce these findings. A 2004 study  found that new lanes are filled to capacity in just a few years.* In 2009, a National Bureau of Economic Research report  concluded that building additional roadway almost always leads to a corresponding increase in traffic. The report’s data “suggest[s] that an average extension of the interstate network does not result in sufficient travel time improvements to justify its cost.” I could go on, but you get the point.

Even measures like carpooling can’t justify more lanes. In Stockton, the Interstate 5 lane widening may feature High-Occupancy Vehicle (HOV) lanes, though Bay Area researchers found that added HOV lanes actually increased congestion while not encouraging carpooling.

There is no reason to think that the fate of traffic in Stockton will be any different. This is not to say that there will be absolutely no good to come of these projects. Our share of Interstate 5 is in dire need of repaving as poor road conditions diminish fuel efficiency and exacerbate wear and tear. And of course any money being spent here on construction surely helps the local economy. Even at their onset, these new lanes probably will ease traffic, if only for a few years. However, with a price tag of over $500 million, are these projects worth the cost? I personally do not believe they are, especially when you remember that 1,025 trees were uprooted— without a commitment from Caltrans to replace them– to make room for these new lanes.

The state and region would be much better served investing some of this highway money on overlooked and underfunded transportation modes, such as rail and bike lanes. At the very least, priority should be given to projects that can actually make driving more efficient, such as renovating bridges and repaving. Simply put, the cost of widening highways is not worth the benefit.

*This study and the STPP study are quoted from “Walkable City” by Jeff Speck.

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Categories: Community Commentary, Transportation

Author:David A. Garcia

David A. Garcia created SCL in March of 2012. Garcia is a Stockton native with a background in urban policy and planning, holding a Bachelor's Degree from UCLA as well as a Master's Degree in Public Policy from the Johns Hopkins Institute for Policy Studies. He currently serves as the Policy Director at the UC Berkeley Terner Center for Housing Innovation. David was also COO at Ten Space, a real estate development firm focused exclusively on Downtown Stockton, and continues to advise on their projects. Prior to that, he worked three years as a researcher/analyst for a Congressional research agency in Washington, DC. The views expressed on this site are entirely of the author's

5 Comments on “Why widening Interstate 5 in Stockton is not worth the money”

  1. Joel
    January 22, 2013 at 10:56 am #

    agreed. We need just look to the South East of Stockton at the Tracy project. How many times have I sat in traffic on that new and “improved” section of freeway…
    The other thing to consider about our section of I5 is the view from it and the money that should have been spent to improve it. I know to many that sounds shallow, but understand, thousands of out of town/state drive through this section of 5 everyday (regardless of how many lanes there are). It’s marketing. Make the views from 5 more appealing and more people will stop and spend money. Right now most of the off ramps look like they lead into a carjacking waiting to happen. We’ve needed a repaving for a long time, it just seems they needed to look at the bigger picture while planning the project.

  2. Chris Mondragon
    July 9, 2013 at 11:30 am #

    I don’t care too much about the widening. I care about the cracks and holes on I-5. If the widening takes care of that, I am game.


  1. Blog: I-5 widening not worth the money - January 22, 2013

    […] Stockton City Limits has a post today about the on going construction on Interstate 5 through Stockton. Though the blog’s author David Garcia supports improving the surfaces, he says the congestion relief provided by the new lane would eventually be lost because of something called “induced demand.” […]

  2. Urban Mobility Report: Stockton traffic not so bad « Stockton City Limits - February 7, 2013

    […] While some of the report’s data appears a little circumspect (I really don’t think commuters in Washington, DC leave almost 3 hours ahead of time for a 30 minute trip because of traffic. Also, the report lists Stockton metro’s population at around 400k, which is more than 200k lower than it really is), its real value lays in the ability to compare across cities and over time. For Stockton, we can see that our traffic situation is fairly ideal, especially for a city of this size, and has actually improved since the mid 2000s, which begs the question: why is $500 million being spent to widen Interstate 5 and Highway 99? Is it really worth spending hundreds of millions because of an extra 2 minutes spent in traffic on a 20 minute drive? Definitely not, especially when you consider that building more lanes won’t alleviate congestion in the long run. […]

  3. Why Stockton needs to embrace biking | Stockton City Limits - May 7, 2013

    […] Installing bike lanes is a bargain when compared to the costs of widening or even maintaining an existing road. One mile of bike lane can cost around $60,000 in California. Not cheap, but consider that it’s costing $262 million to repave and widen Interstate 5 in Stockton. A tiny fraction of this amount could be used instead to build an impressive biking infrastructure. With just one eighth of the total it is costing to revamp I-5, Stockton could install nearly 55 miles of bike lanes  (see my earlier story on why widening I5 is a waste of money). […]

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