Smart Roads Are What Driverless Cars Need

Smart Roads can tell your car where to go — and they’re not that hard to build.

Imagine you are stuck in stop start traffic, your left leg is killing from the constant use of your clutch or your rear end has fallen asleep. Nightmare, right? Now imagine sitting in stop start traffic but not having to worry about anything, because everyone’s cars are automated, everyone’s cars know where they are, what the other vehicles around them are doing and what’s up ahead. But it’s not just the driverless cars doing all of that for you, it’s the smart roads too.

By reducing the number of cars on the road, self-driving vehicles could cut traffic, emissions, and urban spreading, while improving safety and saving money for the millions of households that would no longer have to own a vehicle.

Does this mean we’re about to adopt a futuristic army of driverless cars in our cities? Not just yet as navigation is an obstacle to overcome. Car manufacturers teach their cars to move by employing fleets of drivers who travel the streets in ordinary cars, scanning for changes in previously mapped roads. These changes are pushed, once a month, to driverless vehicles, so that the cars can interpret the roads correctly as they drive.

This works for a lot of what vehicles encounter. Some things—like streets, curbs, and roads don’t change for years, while other, temporary things—like traffic delays and road closures — can be crowdsourced by mapping devices. But driverless cars need to “see” some information that’s miles away in real time — such as a dog running into the street, a speeding ambulance, or a swerving driver.

Smart Roads

Building roadside sensors along our streets and motorways so cars can navigate them sounds like an expensive dream. But, a series of advances are coinciding to make such a system possible. Fifth Generation wireless, or “5G,” is a wireless broadband standard that’s currently under development and will improve on our current networks in ways that will be useful for driverless vehicles. A 5G system will include denser wireless networks speeding up connections and will also have broadcast capabilities, allowing networks to distribute large amounts of mapping data without time lags.

Sensor technology is also getting better and cheaper; to sense and react to the world, driverless cars use a series of technologies, including radar and cameras.. Lidar systems emit invisible laser light that reflects off of objects in view; then, the lidar system times the speed of the reflection to measure distance, creating a precise, three-dimensional image of the world. The best systems don’t come cheaply. The distinctive spinning lidar unit that you see on top of Google’s automated Lexus SUVs cost about $75,000 per vehicle.

Mounting these sensors to cars comes with drawbacks, especially for vehicles that are only partially autonomous. Car-mounted lidar sensors have a range of 200 meters, and perform best under 100 meters. That means that if a car is travelling between 30 and 60 mph, a passenger will have around 5 to 15 seconds of warning of an unusual situation up ahead.

These takeover requests can be jarring, irritating, and dangerous. Researchers at Virginia Tech found that passengers took an average of 17 seconds to begin driving in such situations. Passengers on road trips, who might be sleeping, eating, or watching a movie would need even more warning. Roadside sensors, however, would allow vehicles to “see” activity far ahead on their routes. With roadside sensors, passengers might have minutes, instead of seconds, of warning. Smart roads could also provide more descriptive information to vehicles, letting them know, for example, that the person-shaped object near a sensor is a Halloween scarecrow, not a child.

There are other benefits. Car-mounted sensors are often confused by road materials (a shift from dirt to gravel), reflective buildings, bridges, or even the weather. Roadside sensors not only mitigate these problems, but also reduce the computing load on car-mounted systems, because the vehicles have to make fewer snap decisions.

Smart Roads

A system of roadside sensors would require infrastructure

Cities and counties have to bury protective ducts for wires, construct poles, and permit wireless sites on public property. In large cities, which typically have decades-worth of underground structures competing for space would be tricky.

But over the next decade this infrastructure is going up anyway, as cities prepare to offer high-speed internet access. Overlaying a roadside sensor system would be relatively easy, and in rural and urban areas, where fewer approvals are necessary, such a system would be have a greater impact. Semi-automated vehicles might provide an alternative to public transportation. Crowd-sourced mapping isn’t as effective in rural areas, as there’s not enough traffic for real-time updates, making roadside sensors the only reliable option for self-driving cars.

Smart Roads

This is not to say that self-driving cars are the only thing to be benefited by deploying sensors to our roads. Cities could use sensor data for conducting traffic studies, pushing out real-time public bus alerts, increasing parking space occupancy and enhancing pedestrian safety.

As the evolution of the internet, operating systems, and phone standards show, there are tremendous social benefits when firms are freed to iterate and compete. But the installation of roadside sensors require a forward-thinking government, who have the legal authority over most rights-of-way and wireless siting. They can help usher in this transportation revolution.

Smart Roads