Autonomous Vehicles and the Future of Roadway Design and Construction
Are we prepared for this major shift in transportation?
- Autonomous vehicles behave differently from human drivers and the widespread adoption of AVs poses new challenges to the traditional highway design approach.
- Researchers have concluded that self-driving cars are far more likely to follow pre-defined paths on the road, unlike human drivers who typically follow a varying path and wear the highway more evenly.
- Engineers are developing new approaches to reinforce roads in selective areas, including structural grade beams in the zones of the highway most likely to be degraded.
Transportation engineering is one of the major disciplines within the Civil Engineering profession. Hundreds of thousands of students every year graduate with a degree in Civil Engineering and choose the career path of a highway or roadway designer. Designing roadways means you must design complex interchanges, consider pedestrian needs, monitor live traffic patterns, perform traffic flow and density analyses, and more.
The origins of transportation engineering date back to the early 1920’s when automobiles first started to replace horse-drawn carriages. Now, precisely 100 years later we are faced with a new replacement, autonomous vehicles (AV).
By definition, an autonomous vehicle, or a driverless vehicle, is one that is able to operate itself and perform necessary functions without any human intervention, through the ability to sense its surroundings.
Self-driving cars are expected to ease our daily commutes, make driving safer, and boost efficiency in everyday life. Elderly people who are unable to drive safely in traditional vehicles, for example, will be more mobile thanks to their AV. However, in terms of infrastructure, everything from streets to curbs to sidewalks will need to change when the autonomous car makes its official debut. And while a set timeline may not be in clear view yet, the day is definitely coming.
So with countless changes coming into the automobile industry, such as electric and autonomous vehicles, where does that leave the roadway designers and builders?
A multidisciplinary team at the University of Minnesota — including the Minnesota Design Center, the College of Science and Engineering, and the School of Public Affairs — is researching how shared AVs will affect community health, equity, livability, and prosperity.
One major change was noted in a 2018 pilot project for autonomous vehicles using buses on a programmed route. The project demonstrated repetitive driving over the same roadway surface causes faster wear and tear on pavement and eventually causes ruts in the road. Unlike manual driving now where humans are unpredictable in how much they swerve along and across a lane, a programmed AV would likely stick to its script. This presents a major issue because roadway maintenance today is already quite a disruption to the flow of everyday traffic. If there is one thing people around the world can agree on, it’s that losing a lane to construction or merging lanes for roadwork are some of the most annoying things you can encounter on your commute.
How do we make sure that we won’t be creating more roadwork in the future? Changing the way we build our roads. Rather than using asphalt which would wear down easily, structural grade beams with cast-in-place concrete could replace roads. The wear and tear would be removed from the equation and self-driving cars could flourish with this kind of roadway support. Additionally, the shift from impervious asphalt to grade beams with pervious concrete would cause a positive ripple effect through the surrounding built environment. Take a look at the renderings below provided by the Minnesota Design Center. The difference between a collector street and a shared green space is dictated by the kinds of roadways and cars we use.
The typical collector street has relatively low green space and an inability to collect stormwater. The shared green street, however, could accommodate almost 30,000 SF of greenspace as well as stormwater collection from the permeable nature of a concrete road. Even overhead streetlights could be removed, reducing the effects of light pollution in cities and suburbs since the roadway itself would no longer need to be illuminated. Bollards along the road would likely illuminate the adjoining sidewalk and bike paths.
While AVs would need to share the road with human-driven vehicles for a certain period of time, Tom Fisher, a professor from the University of Minnesota, expects that driving itself will eventually be banned in urban and suburban areas and reserved only for the countryside. He compares this scenario to what happened about 100 years ago when cars and trucks began to replace horses.
“We discovered that having horses and cars on the road at the same time doesn’t work very well,” Fisher noted. So today, “we relegate horses to the countryside, and you can’t ride a horse down a city or suburban street. In the same way, within a couple of decades, you won’t be able to drive down a city or suburban street.” — Tom Fisher
While it’s not happening tomorrow, we can anticipate that in just 15 to 20 years from now, highway and street design and construction will look very different than it is today. The changes will include not only new designs and construction but also the manner in which funding is secured for transportation, the level of services expected from third-party providers, and exactly how those services will be delivered.
The possibilities presented by AVs and the redesign of roads will inevitably provide a huge opportunity for the civil engineering community to envision and create a different kind of infrastructure that is both environmentally friendly and safer for people everywhere.
