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How to Improve I-25 Traffic Without Spending Big Bucks

Posted by Mike Salisbury Fri, 07/14/2017 - 02:01 PM Categories: Transportation

Use market forces to help highway travelers for the long-term


I-25 in Denver on a typical workday morning. Photo: Andy Cross/ Denver Post/ Getty Images

Anyone who travels on highways in the Front Range knows that congestion is a major problem in the Denver metro area and, based on expected population growth over the next 30 years, it’s only going to get worse.

The traditional solution, expanding the highway network to relieve congestion and accommodate additional demand, is both unaffordable and ineffective.  The Colorado Department of Transportation has said it needs an additional $1 billion per year to maintain and expand the existing highway network, but the department’s main source of revenue, motor fuel taxes, actually is losing value because of inflation. The high cost of highway expansion makes it difficult to add lanes in a time of declining funding. 

Even if Colorado does find significant new revenues for transportation (which I strongly support), added lanes alone would not untangle front range congestion.  Multiple studies show that while increasing highway capacity might temporarily reduce congestion, in the long run it only encourages more people to drive until congestion returns to high levels.  Imagine trying to stop obesity by loosening your belt: you’re not solving the problem, only buying yourself a little more time.

One compelling example is the $1.67 billion Transportation Expansion Project, commonly called T-REX, which expanded Interstate 25 and added transit service parallel to the highway through southeast metro Denver.  The project started in 2001, finished in 2006, but just four years later – in 2009 – congestion had returned to the level experienced before construction began.  The accompanying rail line provides a fast, uncongested trip for many travelers, but the highway expansion had no long-term benefit in reduced congestion, according to CDOT’s congestion measurements. (Please see the chart at the end of the text.)

What if there was a way to increase mobility on the existing road, and improve transit and other options, at low cost and without having to add lanes? This sounds like magic, but it really just requires a smart approach to using market forces to optimize the use of our existing highway lanes.

The idea actually is very simple: Convert existing highway lanes into high-occupancy toll (HOT) lanes. This relatively low-cost alternative can increase the number of people using a roadway and ensure a congestion-free travel option. The change takes less time to implement than adding entirely new lanes, and certainly costs far less money. Benefits can be maximized by using the revenue generated by the tolls to invest in improved access to transit, expanding and upgrading biking and walking infrastructure, and additional alternatives such as carpools and vanpools.

Conversion of existing lanes to managed lanes, along with aggressive promotion of alternatives to driving alone, can benefit all types of travelers and give them more choices, without increasing congestion in the remaining general purpose lanes, all at much lower cost than trying to expand the highway.

The transportation advocacy group TransForm did an analysis for Highway 101 in the Bay Area and found that shifting existing capacity to HOT lanes would move more people, move them faster, and at less cost than expanding the highway.

Ironically, a top candidate in Denver for such a lane conversion is I-25 through the T-REX area because of the severe congestion there, along with no realistic options to further expand the highway.

As part of a white paper, Managed Lanes and Other Strategies to Improve Mobility on the I-25 South Corridor, SWEEP analyzed this section of I-25 and found that there could be significant benefits from converting one lane in each direction to a HOT lane, then investing the revenue in transit passes and connections to transit particularly for the first and final miles of popular commuter routes.  This win-win approach would give drivers access to HOT lanes where congestion would be greatly reduced. It further would allow more people to use additional, affordable, effective and efficient transit instead of driving. Meanwhile, traffic in the remaining “free” lanes would be no worse than before the changes.

This method optimizes the use of the existing highway, and will give travelers new options that will save them time, whether they choose to pay a toll when they are in a rush, or take the train because there are now better first- and final-mile connections to the transit stations.

In a world of extremely limited transportation funds, the idea should appeal to officials trying to manage limited budgets by make the best use of existing infrastructure.

Maybe it is time to try something new.

For an expanded and more detailed version of this blog post see Improving Mobility without Building More Lanes

View User Profile for Mike Salisbury Mike Salisbury is the Senior Transportation Associate in the Transportation Program at SWEEP. The transportation program focuses on strategies to improve the fuel efficiency of the vehicle fleet and to reduce motor vehicle use. Mike holds a Masters' degree from the University of Delaware's Center for Energy and Environmental Policy, where his research focused on transportation systems and renewable energy.

Comments

Mon, 07/17/2017 - 08:56 PM
Steve
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I wonder if all of the assertions are true:  1) "Converting a lane to a Hot lane will not slow down traffic on all the other lanes". There are more.

THis paper assumes that the traditional funding (federal and state gas taxes and Federal general fund) are not ever going to be available.  If you assume those things as axiomatic, then you will get them to be true. I prefer to accept obvious truth: Improved gas mileage and electric cars will reduce the gas tax revenues per driven mile.  However this can be accomodated  with alternative funds. On the federal general funding, the issues is different. The Fed Govt under Reagan and those to follow wanted to make The American Rich be Richer....  the consequences were that we have less money for education, less for Health care, Less for Infrastructure.

Roads, Bridges, Airports, etc have faltered. Schools and Universities have lost funding. Students are bankrupt as  they graduate.

And the rich get fatter and fatter ... and demand more tax cuts.... for themselves. 

That is what we need to accept as fact not as a mandatory future. For the future

We need Bernie's plans.... Yes Sir, we do!

 

 

 

Tue, 07/18/2017 - 03:15 PM
Will Toor
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Hi, Steve. Our analysis looked at how many drivers would likely switch over to carpooling and public transit if the revenue from the HOT lane was used to provide better connections and incentives for carpooling and transit use, and concluded that this would be larger than the number of cars that would switch from the Hot lane to the remaining general purpose lanes - that is the basis for our claim that this would not make traffic worse in those lanes.                 We do think that it is very unlikely that the level of public investment would be high enough to build all the roads that CDOT has in its plans; but even if there were enough money, where would you expand something like I-25 through T-REx? The walls of the trenches abut existing buildings. And even if you did somehow solve that (maybe by double decking the highway), the induced demand would just fill the new road back up until it reaches an equilibrium level go congestion.

 

 

Wed, 07/19/2017 - 09:14 AM
Steve
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Will.  I agree with you that it is unlikely that money will be available to improve I-25 through T-Rex.  I apologize that my post was not clear on my proposal.  Instead of having a HOT lane with HOV3, I propose turning one of the lanes into an HOV2 lane.  When drivers in the General Purpose Lanes see that the HOV2 lane is travelling at 55 mph because traffic is limited to 1,400 vehicles per hour, drivers will either carpool, vanpool, or ride The Bustang so that they can travel in the HOV2 lane.  This will reduce traffic in the two General Purpose Lanes and traffic in those lanes may move at 35 mph.  I like this suggestion because it is more equitable and doesn't allow the rich to buy themselves out of traffic jams.  I also think that the RTD light rail stations should not charge Out-of-district drivers for parking at their southern stations.  This would encourage more drivers from Castle Rock to ride the Light Rail and use excess Light Rail capacity and would consequently diminish the number of vehicles in the General Purpose Lanes.

Wed, 08/09/2017 - 12:22 AM
csjshi
View User Profile for csjshi

The idea actually is very simple: Convert existing highway lanes into high-occupancy toll (HOT) lanes. This relatively low-cost alternative can increase the number of people using a roadway and ensure a congestion-free travel option. The change takes less time to implement than adding entirely new lanes and certainly costs far less money. Benefits can be maximized by using the revenue generated by the tolls to invest in improved access to transit, expanding and upgrading biking and walking infrastructure, and additional alternatives such as carpools and vanpools.

Thu, 08/31/2017 - 05:41 AM
Sumit
View User Profile for Sumit

THis paper assumes that the traditional funding (federal and state gas taxes and Federal general fund) are not ever going to be available.  If you assume those things as axiomatic, then you will get them to be true. I prefer to accept obvious truth: Improved gas mileage and electric cars will reduce the gas tax revenues per driven mile.  However this can be accomodated  with alternative funds. On the federal general funding, the issues is different. The Fed Govt under Reagan and those to follow wanted to make The American Rich be Richer....  the consequences were that we have less money for education, less for Health care, Less for Infrastructure.

Thu, 09/07/2017 - 01:03 AM
sambhav
View User Profile for sambhav

This sounds like magic, free printable algebra graph paper but it really just requires a smart approach to using market forces to optimize the use of our existing highway lanes.

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