Autonomous vehicles are driving significant and exciting technological developments, with advanced sensors and neural networks being prime examples. But the technology needed to enable autonomous driving goes beyond the vehicles themselves. The roads on which they operate can also benefit from those same advances, bringing about new levels of safety and navigation. This is an area that’s gaining increased prominence, although not from all stakeholders. 

For example, in 2021 the US Department of Transportation published policy guidance for self-driving cars. Although this guidance outlines a comprehensive plan for manufacturers to ensure the safety of their vehicles, it doesn’t provide any data for road builders or the drivers themselves. This narrow focus is perhaps understandable given that semi-autonomous cars still represent only a tiny fraction of all vehicles on the road and forecasts don’t see this balance shifting any time soon.

However, questions remain. Should governments spend money on smart roads that benefit a minority of users, and is it possible that such technology might even make the roads less safe for human drivers? 

While this debate continues, those designing and building autonomous vehicles are actively pushing for enhancements to the road networks themselves, and some governments are responding.

Lane markings need to improve

Vehicle manufacturers suggest starting with an improvement that should be free of controversy, which is to simply mark roads correctly following governmental standards.

In 2016, the mayor of Los Angeles, Eric Garcetti, boldly stated that the city would be preparing its roads for the forthcoming growth in autonomous vehicle numbers. During that press conference, Garcetti got into a self-driving Volvo, which had difficulty driving itself. According to then-president of Volvo North America, Lex Kerssemakers, who was sitting alongside the mayor, this was because the car’s cameras couldn’t pick out the faded road markings.

Kerssemakers is not the first autonomous vehicle maker to call out the condition of the roads. Tesla’s CEO, Elon Musk, showed reporters two sets of overlapping lane markings on a freeway near Los Angeles. The duplicate lines could cause Tesla’s autonomous cars to track the wrong markings and consequently move out of their lanes. To mitigate that problem, Tesla mapped each lane in advance, negating the need to rely on sensors.

Smart roads and infrastructure

Another key issue for self-driving vehicle manufacturers is the lack of consistency when it comes to signs, signals, and markings. Cross a state or national boundary, for example, and the design and format of these critical elements can change dramatically.

Beyond simply improving conventional road elements, we’re also seeing a shift toward smart solutions, such as embedding sensors in roads and traffic signs. The push to create smarter roadways dovetails neatly with proposed communication standards, such as automotive LTE and dedicated short-range communications (DSRC). These technologies enable vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I) communication, both part of the broader vehicle-to-everything (V2X) umbrella.

V2V systems are similar in concept to the Traffic Alert and Collision Avoidance Systems (TCAS) used in aviation to alert pilots to potential collisions. Following a campaign lasting over ten years, the US National Highway Traffic Safety Administration seems close to gaining political approval for mandatory transponder-based V2V systems.

While V2V and V2I were originally envisaged as driver-assisted technologies, both can also be applied to self-driving vehicles, complementing sensor data and sharing it with other vehicles on the road. Researchers in Baidu, China, have suggested additional benefits. For example, the hand signals made by a police officer to a stream of oncoming traffic cannot currently be interpreted by a self-driving car; the human driver would need to take control to follow the instructions. Baidu has outlined how V2X technology could help overcome this issue by providing traffic control officers with beacons that send instructions to the traffic via V2I networks.

What does this mean for human drivers?

The push to alter roads for the benefit of autonomous vehicles could result in controversial outcomes. For example, it’s possible that we could end up with roads optimized for self-driving vehicles but with reduced safety for human drivers. Take this a step further, and you could have a situation where human drivers are forbidden from driving on certain roads.

Consider the fact that autonomous vehicles could have a greater awareness of their surroundings and can react faster than humans. Roads for such vehicles could be narrower, thereby reducing costs and freeing up valuable real estate. Cars could also travel faster and with less space between them, while V2I technology could eradicate the need for road signage and traffic lights. But all of this would rely on removing humans from the autonomous equation.

Gradual changes

The idea of changing our roads for the benefit of self-driving vehicles will likely remain a contentious issue to which we may never get a definitive answer. More likely is that smaller-scale alterations will happen bit by bit, without specific intervention from governments.