Experts weigh in: Will autonomous vehicles mean more congestion — or less?

Here’s a simple little multi-billion-dollar question for Utah’s transportation planners:

Will autonomous vehicles, smart highways and the sharing economy increase congestion or reduce congestion on our highways?

It’s a multi-billion-dollar question because advanced technology and the sharing economy are coming very quickly to our vehicles and highways – along with rapid population growth. Meanwhile, major highway and public transit projects cost billions of dollars and require many years of planning and construction.

Projected future travel levels and resulting expected congestion drives transportation planning and the selection of projects to be developed. Understanding the impact of autonomous vehicles and smart highways will be key to development of the long-range statewide transportation plan.

If the high-tech transportation future slows congestion, then perhaps some of the planned projects can be scaled back or even eliminated. But if congestion is going to increase because of improved mobility and population growth, then projects need to be accelerated and expanded.

If we build the wrong infrastructure for the future, a lot of tax dollars could be wasted.

Here are some questions that need to be answered:

–Will coming “mobility on demand” increase congestion because travel will become easier and more convenient?

–Will people with disabilities, the elderly, and even children be on the roads in higher numbers and use public transit less, thanks to driverless cars and easy mobility?

–Will technology allow higher vehicle density on the roads with fewer accidents, increasing capacity and throughput of existing roads and highways?

–Will commuters be less likely to use public transit because of the convenience of autonomous vehicles and the ability to use phones and laptops en route to a destination – even if a trip takes longer?

–Or will public transit see higher use because increased mobility will create such congestion that public transit will be a faster and more convenient option?

–Will mobility on demand help solve the “last mile” challenge for public transit?

–Will the sharing economy and autonomous vehicles mean less vehicle ownership, but more vehicle traffic because calling for a car when one is needed will result in a car driving empty for some distance, which will increase congestion more than if an owner drives it out of a garage? 

Because of the importance of this discussion, went to the experts for answers. We asked four Utah transportation leaders if they think advanced transportation technology will increase congestion or decrease congestion:

Carlos Braceras, executive director of the Utah Department of Transportation. These are important questions that many transportation professionals around the world are trying to understand and to be prepared to realize the amazing benefits. The transportation system of the future will be truly revolutionary; we will have the safest system ever, moving rapidly towards our shared goal of zero fatalities. We will have a seamlessly integrated multimodal system, where users will have options on how and when trips are made. The focus will be on the journey, and not on the mode. Based on your goals (travel time, costs, level of engagement with the journey, desired activity, social interaction, etc.) you will be presented with the best option. 

The future isn’t one that just happens, and all of a sudden we all look around and realize it’s here. It is happening right now, and most of us will just think this is the way it always was. So, making absolute statements about the benefits is difficult when you are considering that the baseline is always moving. And yes, the technology changes that are needed are happening faster than ever, but I feel that we don’t even know what the technology will be in 5 to 10 years. Remember, 10 years ago we were just hearing about this thing called an iPhone; now we can’t imagine our life without it.

I believe that we will have more mobility. People, goods, data, ideas will move more in the future then they do today. I believe that we will have less of what people think of as congestion, because our integrated, connected transportation system will do a much better job of optimizing the journey. I believe that mobility as a service, when it’s seamlessly integrated into our mass transit system will help transit be the mode choice for more of our population. 

I am very optimistic about the future and with the amazing partners we have I know that Utah is going to help lead our nation to realize Zero Fatalities and Enhanced Mobility to provide that vital foundation to our economy and quality of life.

Matt Sibul, Utah Transit Authority government relations director. Autonomous vehicles and the sharing economy are here, and they are growing stronger by the day.  Probably like most of you (or perhaps yourself) I have several friends and neighbors who have pre-ordered the yet-to-be released Tesla Model 3.  Every single one of these affordable electric cars will have self-driving hardware and software pre-installed.  Anyone can get on YouTube and see how this is already working, almost in a shocking way all around us in more expensive Teslas.

But at the end of the day, what gives me confidence that there will always be a place for transit in a potential world of self-driving, on-demand cars is simple—geometry.  We are constrained in the width of our roadways, and when too many cars fill those roadways it leads to traffic congestion.  No matter who—if anyone—is behind the wheel.  In the space that just one fully loaded bus of 40 people occupies, it would take a city block of a one lane road to fit that many people, even in autonomous cars.  When you consider that one TRAX train can move up to 600 people at a time, you get the picture of the geometry problem that relates to autonomous cars and congestion.  And in a state that is the fastest growing in the nation, we all know that car traffic will increase accordingly, unless we plan for the future.

As for the sharing economy, as a transit person I will fully admit to using UBER and Lyft once in a while; but that’s in addition to riding my bike, walking, riding buses and trains, and yes, EEEEEEK—driving.  My point is that we should not be forcing labels on people—especially Millennials—when it comes to mobility.  Transit is evolving to co-exist, and hopefully thrive, in the presence of the sharing economy.  I like to joke with people that public transportation was the innovator here, as we pioneered shared rides with stagecoaches, trains, and buses!  But the bottom line is that people just want to get around in the most effective, inexpensive, and relatively quickest way possible.  Especially for younger people, one day that means a train, the next a GreenBike and walking, and the day after that it’s Lyft.  That’s not a label, that’s just life.

There should be no pride of ownership when it comes to getting transportation right for our stakeholders who would like to travel without owning a car.  UTA has focused in the past few years on providing service to the more heavily travelled corridors along the Wasatch Front.  That means trains, Bus Rapid Transit (BRT) and frequent regular buses on arterial corridors, which reduces congestion and helps with the geometry problem discussed earlier.  That leaves many neighborhoods without good transit service.  But it doesn’t mean that UTA should strive to jam large 40 foot long buses down every neighborhood street.  In these cases, smaller shared ride vans, circulators, and bike/walk options would be a better fit.  These don’t need to be owned by the transit provider, but they surely need to be integrated into the transit system, with a seamless way to pay your fare.  There are a lot of smart people working on these things at a local, regional, and national level, and I’m convinced of our bright transportation future, no matter the mode.

Dana Meier, WSP (formerly Parsons Brinckerhoff) area manager and transportation engineer. As with most modern problems, technology is one of the important tools to mitigate or manage our traffic congestion. With the population along the Wasatch Front expected to double by the year 2050 and the major transportation corridors reaching full build-out, traffic congestion is likely to get worse unless technology can offer some solutions.

As autonomous/connected vehicles (ACVs) are integrated into our transportation systems, we can remove the most unreliable element from the system, human error. This should result in a more reliable and safe transportation system.  ACVs will eventually communicate with each other as well as with the infrastructure. This will allow narrower lanes and less stopping distances between vehicles that will likely increase the current theoretical limit on freeway capacities, giving more bang for the buck on utilizing our existing pavements.

Soon, you may wake up in the morning and have your smart phone notify you that you have an early appointment downtown. It will also notify you of the time you need to leave to make that appointment. The smart phone will communicate with the transportation system to know the fastest, most reliable route available. Your smart phone will also ask if you would like to schedule a vehicle to pick you up at the appointed time and let you know the cost of that ride. It will likely give you an option to leave a little earlier and pick up additional passengers that will reduce the cost of the trip substantially.

There are currently several technologies that offer hope for a reliable, safe and robust transportation system. Managed Motorways (MM) is an example that has been successfully implemented in Australia. Our freeways have a theoretical maximum capacity for throughput, yet we can only achieve 80 – 85% of the theoretical capacity when our freeways are operating at their best. Unfortunately, when we need our freeway capacity the most, they operate at their worst. During rush hour, our freeways may operate as low as 50% of the theoretical maximum.

By incorporating sensors into the freeway and monitoring the traffic and the degradation of the traffic flow, we can adjust the amount of traffic entering the system to maintain the maximum capacity possible, thus improving the throughput and reducing delay on our system.

By combining ACVs and MM the transportation system becomes complete. The ACVs communicate with the system, letting the system know when it will enter and exit the freeway, allowing the system to optimize the number of vehicles allowed on the freeway to maintain capacity. The system in turn can notify an ACV the time that it needs to be at the freeway on ramp to gain access to the freeway thus reducing the delay at the on-ramp.

The transportation system may also communicate with transit and rail facilities and recommend a faster or less expensive alternative for the traveler to reach their destination. This would address the first mile/last mile challenge that UTA faces to improve ridership on their system.

Other technologies that may likely be utilized to reduce congestion are proactive land planning strategies that will bring people together in walking or biking communities where people can live, work, recreate, dine, shop etc all within walking distances. 

There is no single solution to solve congestion but there is a healthy tool box of technological options that can be implemented to manage congestion and improve the quality of life for people living along the Wasatch Front. The future may be filled with challenges, but the future is bright with respect to creating a safer, reliable and dependable transportation system.

Jon Larsen, Wasatch Front Regional Council lead transportation modeler. I would answer this question by saying that it depends. Generally, I believe that travel and congestion will increase because traveling by automobile will be more convenient. 

The reason this is so difficult to forecast is that the factors are interrelated, non-linear, and untested, which all makes this such an interesting topic. A major factor that could lead to decreased congestion is that AVs will likely have fewer crashes than human-driven vehicles, which will allow for smoother traffic flow. However, any gains may be lost due to induced travel demand. In addition, AVs can (in theory) follow each other at closer distances, which makes the freeway in particular more efficient. AVs could potentially double the capacity of our freeways.

However, this assumes that all vehicles will be autonomous. Mix in a handful of human-driven vehicles, and all bets are off. True AVs may be commercially available soon, but the widespread deployment of fully autonomous vehicles is decades away. To achieve the full benefits of AVs, it may require restrictions on human-driven vehicles, which could be untenable politically.

Another factor is the potential for empty vehicles driving around on return trips. Factors that could lower vehicle miles traveled and congestion include the potential for lower personal auto ownership and more auto sharing or using autos as a service, which would free up space for higher and better uses than garages and parking lots, which could result in more compact, walkable places. 

It’s important that policy makers engage in the process and recognize that we’re not bystanders in the evolution of AVs and their impact on our lives. We should set up a vision based on our collective values, and make sure that the technology serves us and not the other way around.

Do we want to use AVs to unlock cheap land for development by enabling more supercommuting? Do we want to use AVs to make urban living more convenient? Do we want to use AVs and the sharing economy to make better use of urban space? Do we want to use AVs to enhance mass transit, or replace it? Do we want to use AVs to enhance mobility for the young, old and disabled? We could end up doing all of these things simultaneously. On a regional level, these impacts could balance each other out, but result in dramatic congestion changes by location. 

The impact on mass transit is an interesting topic to explore. Automation doesn’t change the capacity of vehicles. Large buses and trains will still carry more people than passenger vehicles regardless of who or what is driving them. Perhaps buses could be automated, saving on costs, and allowing for enhanced, more frequent bus service. This would result in lower VMT.  AVs could replace bus service in low-density suburbs, allowing for more responsive service in these areas, while saving money, and freeing up resources for even better bus and train service in the more dense urban areas.