The Mythology of HOT Lanes

In July Virginia Governor Terry McAuliffe stood on the platform of a train station in Alexandria to announce that the U.S. Department of Transportation had granted $165 million for the Atlantic Gateway project.

While this is a multimodal project featuring rail, bus, and highway improvements, it was clearly the latter that most enthused the governor. At one point during his remarks, he declared that because of the road projects, “Today, the congestion is going to end!”

The primary focus of the highway improvements will be an extension of the HOT (high occupancy toll) lanes on I-95 and I-395. The only other speaker after the governor was a representative from Transurban, the controversial company that will operate the extended toll lanes.

McAuliffe. Photo: Kevin Posey
Virginia Governor Terry McAuliffe. Photo: Kevin Posey

Is McAuliffe right to be so confident in the ability of HOT lanes to eradicate congestion? Let’s look at three key arguments often heard in favor of HOT lanes.

Argument 1: Adding HOT lanes reduces congestion in general lanes along the same route.

According to the Federal Highway Administration, HOT lanes — sometimes branded as “express” or “managed” lanes — pull users from the general lanes because they stay uncongested. As usage of the HOT lanes increases, the toll increases. That keeps those who don’t want to pay the higher toll from entering. If enough drivers leave the general lanes for the toll lanes, the general lanes will move more freely.

This argument overlooks the phenomena of induced demand: as capacity increases, traffic also increases, as measured by vehicle miles traveled. The California Department of Transportation, Caltrans, acknowledged this effect could neutralize capacity expansions within five years.

It may not take that long. In Houston, Texas, commuters have discovered that having the world’s widest expressway that includes HOT lanes is no permanent congestion cure. The Katy Freeway is now a staggering 23 lanes wide, but three years after the state allocated $2.8 billion to expand it, congestion returned to its original level and continues to grow.

Though HOT lanes don’t prevent bottlenecks from occurring at toll lane exits, lane extensions are usually justified as an effort to eliminate them — just as highway expansions are typically justified. But no expressway or HOT lane can deliver drivers directly to their destination, and at some point there will be a bottleneck. This is the scenario now playing out in northern Virginia, just as it has after every previous expansion of I-95.

If HOT lanes do not relieve congestion in the long term, how do politicians and planners justify them? Consider this statement [PDF]  from the Washington State Department of Transportation, in a study on Miami HOT lanes used to promote a WSDOT project: “95 Express has improved overall traffic conditions along the project corridor since its inception.”

The WSDOT study, however, only looked at the first two years of Miami data — and even that shows travel speeds were already dropping by year two. A review of figures compiled by Caltrans [PDF] from the Katy Freeway, I-95 in Miami, and Georgia’s I-85 shows that short-term data are often cited to sell a HOT lane project.

Argument 2: Converting HOV (High Occupancy Vehicle) lanes to HOT lanes doesn’t increase overall congestion in those lanes.

The sight of HOV lanes sitting mostly empty during rush hour has proven irresistible to commuters, politicians, and planners, especially in a time of limited infrastructure budgets. When the Reason Foundation pitched the concept of converting HOV lanes into HOT lanes, it claimed: “In most cases the conversion of an existing HOV lane to a HOT lane should be more than self-supporting from the new toll revenues.”

Critical to justifying a conversion is showing that current HOV users, such as buses and carpools, won’t be adversely impacted by the addition of paying users. In Reason [PDF], Robert W. Poole Jr. and C. Kenneth Orski recommend a data-driven approach to downplaying this risk:

The analytical case may involve computer modeling to show that overall traffic flow will be improved in the corridor in question, reducing the extent of stop-and-go traffic (and hence, reducing running emissions) in the existing lanes while guaranteeing the smooth flow of traffic in the HOT lane.

Citing short-term studies from the 20th century may bias the modeling to yield favorable results. More recent in-depth studies show that traffic does, in fact, slow in reserved lanes after conversion. On California’s I-680 in the southbound reserved lanes, travel speeds dropped significantly [PDF] after the conversion to HOT lanes in 2010. The cost to local, state, and federal taxpayers for this project was $195 million [PDF].

If converting HOV lanes to HOT lanes doesn’t improve vehicle flow, idling isn’t reduced. Idling is considered a cause of CO2 emission, since vehicles must burn gasoline for longer periods than would otherwise be the case in free-flowing traffic. The alleged reduction in idling is an argument used by HOT lane advocates [PDF] in cities that are out of compliance with the Clean Air Act. Evidence indicates that argument is unjustified.

Via D.C. Metro
Image: DC Metro

Argument 3. HOT lanes help boost transit use and carpooling.

“High occupancy” implies HOT lanes are for vehicles with more than just one person. According to the HOT lanes marketing toolkit from the U.S. Department of Transportation, “HOT lanes encourage carpooling and other transit alternatives while offering vehicles that do not meet standard occupancy requirements another option for providing more reliable travel times.” However, a 2013 FHWA white paper [PDF] showed that out of HOT lane studies in Minneapolis, Denver, Atlanta, Miami, and San Diego, only Minneapolis saw a clear improvement in carpooling usage. Results in other cities were neutral, inconclusive, or, in the cases of Atlanta and Miami, negative.

Slide: FHWA
Image: FHWA

Other studies show the negative impact of HOT lanes on carpooling. Researchers at Texas A&M [PDF] found that “…it does appear that carpooling is often negatively impacted by converting a HOV lane to a HOT lane.” They continued: “In theory, the added choice of traveling as a SOV on the HOV lane may result in some carpools breaking up.” Researchers at Boston College [PDF] reached the same basic conclusion.

In essence, giving motorists the choice of paying a toll so they don’t have to ride with others encourages single occupant vehicle travel. Does the same effect hurt transit?

Not according to rigorous studies. However, the Center for Neighborhood Technology [PDF] found that, “In practice, many new riders of buses on HOT lanes come from other transit modes and, therefore, do not represent growth in system ridership.” For example, surveys of riders on Miami’s I-95 express lane bus service found that a third of them came from commuter rail. The best that can be said for HOT lanes’ impact on transit use is that it is neutral, though the expenditure of budget resources for no net improvement could certainly be considered a negative.

So, if HOT lanes don’t reduce overall congestion along their routes, worsen congestion in previously existing HOV lanes, and either hurt or fail to improve high occupancy vehicle usage, why build them? Perhaps politicians, desperate to appease angry drivers, are succumbing to a scheme that offers false hope. However, many commuters have begun to lose faith. They are moving to the cities, where they are less dependent on highways to get around. If taxpayer dollars are to be spent effectively, they will have to follow the people.

  • AlexWithAK

    One thing that can be said for HOT lanes is that they are an entry point for paid use of highways. Ultimately, it would make sense to toll ALL congested highways, even if it’s a nominal amount. In that case HOT lanes can continue to be the premium lane but with a price point that truly keeps HOVs and buses running smoothly. Any tolling scheme must aim to provide viable alternatives for those can’t (or don’t want) to pay the toll.

  • JustJake

    How about the concept of HOT cities, and surcharging for use of those?

  • SD70MACMAN

    Another issue with HOT lanes is politicians receiving pressure to reduce or eliminate tolls during certain periods of time.

    For example: WSDOT’s I-405 HOT lanes. The two-year trial period of variable 24/7 tolls was reduced to six months after local politicians, who originally approved the project with a two-year period, backtracked after pressure from constituents. Now, the HOT are free and open to all users except during weekday peak times. With HOV/HOT conversion and new HOT lanes slated to expand, this scenario will likely repeat itself now that people know how to pressure their elected leaders.

  • Vooch

    Riverside Freeway (aka 91) has a stretch of paid HOT lanes with variable pricing – sometimes it’s $15.00, sometimes it’s $2.00

    great system and should be applied statewide

  • calwatch

    HOT lanes are just like HOV lanes – a way to add capacity in a fashion palatable to environmentalists and air quality regulators. HOT lanes will become congested and useless slower than a general purpose lane, but eventually will clog up as capacity is reached.

    I find enforcement on HOT lanes to be questionable at times, as the I-10 express lanes can attest. The tolls are sometimes up to $20 end to end but are still packed, and part of the reason is that people are cheating the system, and there is no automated means of enforcement. Motor officer enforcement is very tricky since you have to pass by a single occupant vehicle and verify the correct occupancy is set while they are passing by at speed. Rarely are HOV lanes totally underutilized, and the tolling mechanism is not dynamic enough to charge extremely high rates for the lane when necessary. HOT lanes can subsidize transit providers, which may be a net positive over the equivalent HOV lane if transit service would not be funded along the corridor, but is a negative if that service becomes more unreliable due to SOV toll payer caused congestion (i..e. LA Metro Silver Line).

  • laldm109

    The issue with HOT lanes is that we are creating haves and have-nots in the highway system. It used to be that everyone, no matter their income level, had to sit in the same traffic on the highway. Now that HOT lanes exist, those that make more money can be assured free-flowing highways for a small fee while everyone else sits in congestion. The danger with this is that those with money are also typically those with power in our society. One reason why transit is so overlooked and underfunded in the US is that, for the most part, those with the power to affect change don’t use it. The general-purpose highway system risks losing influence in the same way and, therefore, funding if those with power/money abandon it and just zip to work on the HOT lanes.

  • Joe R.

    Easy way to solve that issue is to guarantee a speed limit trip. If this doesn’t happen then you don’t get charged a toll when you exit the HOV or HOT lane. This will provide an incentive to enforce lane restrictions. If someone is caught cheating, then you permanently revoke their ability to use a HOV lane in the future.

  • Joe R.

    Certainly true but consider in the places where highways are used a lot often public transit doesn’t exist, nor it is even remotely feasible for it to exist.

    I’ll admit I’m less than thrilled about the concept of buying your way out of traffic congestion. Maybe a better alternative is to start limiting highway access once traffic drops below free-flowing speed. This will of course deny some people use of the highway during peak periods, but it won’t discriminate between rich and middle class.

    Bottom line however is we’ll probably still need to price road use if we want to reduce congestion. Ultimately this will mean car use in the more congested parts of the country will end up being mostly for the wealthy or upper middle class. Again, I’m not thrilled with it but I can’t think of any reasonable alternatives. Right now transit in the US is underfunded because it’s mostly the poor who use it. When congestion pricing forces the middle class into transit there will be a lot more political pressure to fund it properly.

  • Like London?

  • Which is currently undergoing an extension and widening through to I-15 the capacity of which is already spoken for in terms of how many developments are approved and under construction in the IE at the moment. At around $200mn/mile, I’m pretty sure that there are better things that could be done with the money, but it’s a bit late for that now.

  • Vooch

    I Drive often from Newport to Elsinore a Few years ago at Many different Times of the day. My Average door-to-door Speed was typically

    9-12 Miles an Hour

    the 55,91, and 15 are massive freeways often with 7 lanes in One direction. Increasing capacity Is Not the Solution. There Is Too much capacity right now.

    the Solution Is simply to encourage Adjacant work-play-shop-live places. just get People to live 3-5 Miles from work instead of 20-35 Miles would reduce VMT Orders of magnitude.

    it’s a dystopian nightmare.

  • FreeTheMarket

    Great article! My experience working in a state transportation agency has been extremely troublesome. I brought up the topic of “induced demand” and the inaccuracy of travel time measures used to study delay (congestion) like TTI, BTI, PTI (reference Todd Litman’s work at VTPI) to my superior, a civil engineer, and he looked at my like I was speaking witchcraft! He then went on to say that we only focus on what the FED wants, and the FED wants anything that justifies a bigger budget and creating puppets out of state agencies. The more things change, the more they stay the same.

  • Mark

    HOT lanes are a great concept. They provide transportation options with guaranteed trip time. In theory you would get to a saturation point with all HOV riders and buses. We need more apps such as https://www.sameride.com/ to help connect carpollers. This concept is much better than rising the gas tax or adding more GP lanes.

  • keenplanner

    I’m not hot on HOT lanes. The most important thing is to move more people faster. Carpools and buses should have priority. Most HOV lanes with a 2+ passenger requirement are now as slow as the GP lanes. The feds require that HOV lanes be maintained so the min. speed is 45 mph. But the state and counties refuse to go from 2+ to 3+, fearing more congestion in the GP lanes.
    Well, that’s the idea. You’re sitting in traffic while all these carpools and express buses go speeding by.
    States can remove “clean air” vehicles and motorcycles if HOV lanes are too slow. I hope they will remove HOT vehicles if they need to as well, or make the trip VERY expensive for them.
    Great report from TransForm on the issue of converting vs. adding lanes for HOT/HOT use:
    http://www.transformca.org/resource/innovation-required-moving-more-people-less-traffic

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