Will we ever have all-weather self-driving cars?
Consider this: Waymo, Tesla and others have been diligently testing self-driving cars. Waymo alone has logged over 5 million miles. But most of the testing has occurred in California, Arizona and Florida.
What happens in a less benign climate? Suppose that it’s snowing a blizzard and your home weather station reports freezing temperatures. You instruct your all-weather self-driving sedan to drive you 5 miles to work. Will your car say in a soothing Alexa voice, “Sorry, Boss. I can’t see safely through this stuff. Why don’t you call in sick today?” Or will it say, “I’m required to tell you that it’s not safe to drive today. But – you’re the Boss, let’s go!”
Either way, there’s a dilemma. Perhaps you would be bold enough or foolish enough to drive yourself to work. But should all-weather self-driving cars be smart enough to beg off when they determine that it’s truly unsafe?
This blog addresses the question: is an all-weather self-driving vehicle a real possibility, or an impractical dream?
Concerns About Autonomous Cars in Inclement Weather
A few years ago the mere thought of owning a self-driving car seemed like something straight out of a science-fiction movie. Today, autonomous driving technology has advanced so much that we might see our first fully-automated car on the road within the next year. Despite these rapidly-evolving advances, there are still serious shortcomings in autonomous vehicle technology. And one of those is that to date, we have nothing approaching an all-weather self-driving car.
According to the U.S Department of Transportation, up to 22% of all motor vehicle crashes are weather-related. Autonomous cars have been extensively tested on normal roads in regular weather. However, testing still lacks for precarious weather conditions involving heavy rain, sleet, and snow.
To better understand the hazards of all-weather self-driving, we need to understand why the current technology lacks efficiency under certain conditions.
Why is All-Weather Self-Driving So Difficult?
At the beginning of this year Chris Gerdes, director of the Center for Automotive Research at Stanford University stated in an interview that bad weather poses a real problem for autonomous cars. Inclement weather seemingly makes all automated tasks slightly more difficult. In addition, heavy snow, rain and other fluctuating weather conditions confuse the cameras and LiDAR sensors.
LiDAR refers to the car’s light-sensing radar. It uses lasers to map the surroundings, enabling the car to ‘see’ around it. Tesla has chosen not to use LiDAR. However, other manufacturers consider it complementary to other sensors because of its high resolution and ranging accuracy.
Unfortunately, deposits of snow can hide lane markers and obscure road signs. As a result, LiDAR and other sensors cannot see well enough to guide the car safely. As a result, the risk of an accident greatly increases.
How Can an All-Weather Self-Driving Car Navigate in Really Bad Weather?
In conditions where LiDAR and video sensors cannot see clearly, radar sensors can help. Radar can sense moving objects including other vehicles and pedestrians as well as buildings, signposts, and snow. In order for these radars to function properly they would have to be secured either inside the body of the car or behind the windshield to ensure that ice and rain do not block the antennas.
One of the problems with radar as a weather-penetrating sensor is that it has inherently less resolution than optical sensors. In addition, metallic reflections can confuse radar.
Ford’s Map-Based Approach
Ford, in particular, has taken a novel approach toward all-weather self-driving. They have created high-resolution three-dimensional maps to guide driving. These maps not only provide information about the road but also what is above the road such as landmarks and sign posts.
In poor weather, the autonomous car can use radar signals supplemented by occasional signals from other sensors to position itself within a 3D model map. Thus even if snow covers lane markings, an all-weather self-driving vehicle could safely navigate. Of course, it would still need to sense the presence of movable objects such as pedestrians and other vehicles in order to avoid them.
Finland’s Integrated Sensor Technology
Developers from the VTT Technical Research Centre in Finland have created what may be the first all-weather self-driving car. This vehicle, named Martti, is a retrofitted VW Touareg. It has driven as fast as 30 miles per hour on a completely snow-covered road without losing control.
Whereas most other autonomous cars rely heavily on LiDAR technology to guide them, Martti uses a full suite of complementary sensors. It uses multiple radars, three forward-facing laser rangers, a rear-mounted LiDAR and a combination of antennas, sensors and cameras.
There are no plans to put Martti on the streets of the world anytime soon. Instead, the company is looking to sell the software to other manufacturers, helping them improve their safety ratings and ensuring a safer, smoother ride for all.
All-Weather Self-Driving Will Not Arrive Soon
Despite all the hype surrounding autonomous cars, they still have some way to go before they can be deemed completely safe for the general public to use. However, the technology is advancing rapidly thanks to GM, Waymo, Daimler-Bosch, Ford and many other companies.
A safe transition to completely autonomous cars may come surprisingly soon, provided that we limit them to fair-weather use. Certainly, an all-weather self-driving solution may require much more time. Nevertheless, Ford’s 3D mapping and VTT’s multi-sensor integration offer promising ingredients for an eventual solution.
Regardless of how the technology evolves, companies will have to go to great lengths not only to demonstrate all-weather technology, but also to convince regulators and the general public of its safety.