by Michael Brown
Urban freeways provided unprecedented mobility for decades, and helped the United States sustain a strong economy throughout those decades. But their success eventually became their demise. They enabled far-flung lifestyles, which induced demand and congested them faster than we expected. At first it was cheap and easy to convert medians and shoulders to lanes. Unfortunately that enabled even further driving from the next wave of fringe residents. Now it is getting too expensive to expand, and we know that congestion will return soon anyway.
But hey, we’re Americans! Big things are what we do! Yes, the spirit is able, but when we think about that federal debt clock getting close to $20-trillion, a small voice inside gnaws at us, “You already spent all the money, and your children’s money too. Fort Knox is full of IOU’s to who-knows-who? Even if you can get another loan from China – they’re figuring out that you’ll never pay them back – how can you do this in good conscience?” And we respond, “But how can we not? Mobility is life! Mobility is the economy! We can’t earn the money we need to get out of our debts if we can’t get around!”
There Are Solutions! Before you get liquored up at the “Build-Your-Way-Out Bar & Grill” once more, READ THIS!! Earlier articles in this series articulated the benefits of two freeway optimization strategies – congestion pricing and preventive ramp metering (sometimes called “Managed Motorways”). Either system can optimize traffic flow (i.e., eliminate mainline congestion), but both come with negative side effects and political hurdles. That’s why there are few examples! HOT lanes are the baby steps we’ve been able to make because they’re politically acceptable. But the bang-for-buck of HOT lanes is much less impressive than pricing or preventive metering.
Combining Win-Lose, Lose-Win, to Get Win-Win
Congestion drags the economy and creates frowny-faces. I believe that with congestion pricing, virtually everyone comes out a winner in some way. There are huge wins for sustainability and everyone has the option for fast travel at any time of day. But paying to access a freeway is also a visible loss to everyone, and that makes the strategy politically problematic.
Preventive metering also has positive economic effects — new efficiency means things will move! But traditional activity centers may continue to lose out to the fringe because the preventive metering of Managed Motorways tends to reward long trips. That could accelerate sprawl and increase Vehicle Miles Traveled, making its positive effects more temporary than pricing. More on that momentarily…
This article articulates a way to combine these separate ideas to get the benefits of pricing and metering without the negatives, resulting in an “advanced new formula” for freeways that can potentially support 30-50% more peak-period traffic without any new lanes! This advanced formula could guarantee high speeds, but also counteract the sprawl caused by high speeds. This idea requires very little construction to implement on existing freeways, and in contrast to congestion pricing, which requires 100% of people to pay for a 5 p.m. drive, this hybrid system can be free to many and maybe most users at 5 p.m., making it more politically practical.
But wait! There’s more! The first region to implement this new concept will become billionaires! Not only will they free themselves from billions in “Big Dig” construction debt, but they will also gain a major competitive advantage over other states worth billions in higher Gross Regional Product. As mentioned in Who Wants to Be a Billionaire, we used the EDRG’s Transportation Economic Development Impact System, or TREDIS, to test this concept for Salt Lake. That effort suggests that the 30-year accumulated societal value of time saved could be over $50-billion, and the value of more and better paying jobs could be around $12-billion. But before introducing this new concept, first consider its cousins which have many positives, but also many negatives.
Cousin #1: HOT Lanes.
Earlier in this series, I pointed out that when freeways are overwhelmed, they will lose 30-50% of their throughput – dropping from 2,200 vehicles per hour per lane (their maximum potential) down to 1,500 vphpl or less in actual measured flow. That was the case with SR-191 in Riverside, California, which reported average speeds of 15 mph, and average throughput of only 800 vphpl prior to adding HOT lanes. Afterwards, the HOT lanes achieved 65 mph speeds and throughput of 1,600 vphpl, a tremendous improvement! Eighty percent of low-income residents had a positive opinion of the project, since they did pay for the fast lanes sometimes and were grateful for the option.
But the Riverside example has several problems, which are observable from the photos below and their own data. While an improvement from 800 to 1,600 vphpl is very impressive, why didn’t they get to 2,000 or 2,100, given that the opportunity is about 2,200? There won’t be much elbow room at 2,100, but a freeway lane can carry that much without breaking down. In the photo, you can see the free lanes are clearly overwhelmed, while the priced lanes are relatively empty (presumably not higher than 1,600, but visually this looks to be even less than that). This suggests that they are not trying to maximize throughput, but may instead be trying to maximize revenue to pay for HOT lane construction. Or maybe they are trying to guarantee great service – “elbow room” to those who pay the high fare. When facing imminent failure, the system cannot remain free without failing. But if your goal is maximum throughput, then you also cannot charge too much or the lanes end up with low flow because few will pay the excessively high price. With high prices, you create Lexus Lanes that don’t need as much elbow room as you are creating. Continue reading