Driving in thick fog is tough enough for humans, but it seems self-driving cars have their struggles, too. On Tuesday morning, heavy fog in San Francisco caused a bit of a headache for Waymo’s driverless cars. According to the San Francisco Chronicle, five of Waymo’s autonomous vehicles ended up pulling over to a residential street as a precaution. One of these cars even stopped right in the middle of the street, creating more confusion.
This sudden stop caused other drivers to become frustrated as they flashed their headlights and tried to navigate around the halted vehicles. The chaos continued until the fog lifted, allowing the self-driving cars to get back on track.
Waymo, which is supported by Alphabet, acknowledged the incident on Wednesday. They explained that at around 6 a.m., several of their cars encountered extremely dense fog and decided to pull over temporarily. They added that after a brief stop, the cars resumed their routes. Waymo mentioned they have software updates in the works to improve their cars’ performance in foggy conditions and during such parking mishaps.
San Francisco is well-known for its fog, a topic Waymo has discussed in the past. A couple of years ago, they mentioned on their blog that the city’s iconic fog poses challenges for both human and autonomous drivers. Fog varies in density and can affect a vehicle’s sensors in different ways. Sometimes it’s dense enough to leave tiny droplets on sensors, other times it just forms a thin layer affecting visibility. Additionally, fog can trap particles like smoke or pollution, making it even harder to see through.
In their blog, Waymo highlighted their fifth-generation imaging radar, which uses microwaves instead of light, enabling it to see through fog and mist. They also mentioned a new cleaning system designed to keep sensors clear. Despite these advancements, something went wrong on Tuesday.
This incident is just one in a series of issues involving autonomous cars from both Waymo and Cruise, another company backed by General Motors. Both companies are in a race to offer fully autonomous taxi services. Although they are carrying paying passengers, the vehicles are still under stringent regulations as engineers continue to fine-tune their technology.
Just last month, a Cruise self-driving vehicle was involved in a minor collision after being confused by an articulated bus. Fortunately, no one was hurt, but the incident led Cruise to voluntarily recall its fleet of 300 cars to update their software and prevent similar accidents.
In another recent example, some Cruise cars got tangled up in cables that had fallen during a storm because their sensors failed to detect them. These incidents have led San Francisco officials to urge regulators to slow down the expansion of autonomous-car tests until the technology is more reliable.
Eager to avoid stricter rules, both Waymo and Cruise emphasize that their autonomous vehicles have traveled more than a million miles in complex urban settings without any serious injuries or fatalities. They also stress that their systems are continuously being improved.