Around 10pm Thursday evening, a San Francisco Fire Dept. ladder truck T-boned a Cruise robotaxi, making physical the accelerating battle between the SFFD and the robotaxi companies. Airbags were deployed and a passenger in the Cruise complained of a headache and was taken to hospital.
(This is a developing story which has received updates since initial release.)
In a Cruise Blog post the company reports it heard the sirens and slowed immediately on seeing the vehicle. In addition, the California DMV has asked Cruise to reduce its operations by 50% in light of this crash and other events. (See below)
The accident is complex, and there may be potential fault for both vehicles, but mostly for the Fire Department. The Cruise Chevy Bolt was traveling down a one-way street (Turk) going through an intersection with a green light, according to Cruise. The Fire Engine was on call on Polk St. A witness reports it had sirens going. Approaching the red light, the fire truck appears to have moved to the opposite lane to clear traffic and cross the intersection through the red light. Cruise states that this position for the truck “complicated” their tracking of it, though it’s not clear how that affected the situation since they only saw it for a short time.
The intersection has tall buildings at the corners making the corners “blind.” Vehicles on Turk such as the Bolt can’t see an approaching vehicle on Polk, particularly on the right side. The Bolt was also apparently in the right lane, based on the final geometry of the vehicles. The fire truck hit the rear right side of the Bolt, apparently spinning it about 45 degrees, but the fire engine did not travel very far into the intersection in spite of its larger mass.
When an emergency vehicle is running code with a visible light and sirens, other vehicles are required to yield to it and pull off the road as needed. However, this does not mean emergency vehicles can run through red lights and stop signs. The normal red light rules do not apply, but the procedure is for the vehicle to slow, make special sounds (honk or modulate siren) and confirm the intersection is clear, then proceed.
Ideally, the Cruise vehicle should have reacted to sirens and slowed as it came to the crosswalk, where it would have seen the fire engine and stopped. The fire engine should have slowed at its own crosswalk and should have stopped when it saw the Bolt going through the intersection. Neither happened, resulting in a collision. Cruise tweeted that they believed any injuries were non-serious.
While the vehicle should have slowed, it may not be legally required to yield. The California vehicle code requires yielding to an emergency vehicle if it is both sounding sirens and has a visible red light. The lights on this vehicle were apparently not visible until it was close to the intersection. Cruise promotes that it takes extra effort to detect emergency vehicles, so one might argue it should have slowed, by their own standards, but it was probably not legally required to.
Bill Billuomini, who was working at the front desk of the Embassy hotel at the intersection, reported that the sirens were loud and present for a reasonable amount of time prior to the impact, which he heard inside the hotel. Cruise vehicles are equipped with microphones to listen for sirens and attempt to determine their direction even when the vehicle can’t be seen, but for reasons not outlined by Cruise, the vehicle decided to proceed through the green light. It did not visually see the fire engine until roughly 1.5 seconds prior to the impact, it was reported.
Cruise has had a terrible week in the news. It began well, with the granting of an expanded permit for operations in San Francisco and announcements of expansion into new regions, such as Charlotte. It also included a vehicle driving into wet concrete at a construction zone, a traffic jam of 5 vehicles in the North Beach area first blamed on communications problems, but later revealed to be caused intentionally by a pedestrian. At the same time, communications problems did cause delays in resolving problems in the heavy traffic outside a music festival. Thursday night also saw a collision with a car allegedly running a red light at high speed.
This fire truck collision is a terrible cap to the week due to the conflict between the city and Fire Department of San Francisco and the robotaxi companies. In fact, this particular truck, Engine #3, was spoken about at length during last week’s CPUC hearings as one of the busiest and most important in the country. It was not damaged, but it was delayed in its response to a call. The crash took place just blocks from City Hall and the CPUC offices, to pile on the irony.
In addition, even though the city’s pleas were mostly disregarded at the CPUC, the city is stepping up their efforts with more petitions to scale back operations in their town.
Waymo representatives believe their vehicle would have handled this situation. According to Waymo, “Waymo has developed various technologies to detect active emergency vehicles even if they are not in direct view. Like humans, our vehicles can hear sirens and reason about the direction, location, and motion of the active emergency vehicle, importantly including whether it is approaching or receding. When we hear sirens, our vehicle will slow and then depending on how the situation develops, we will either pull over or stop ahead of intersections where there might be crossing emergency vehicles, even if we have a green light. The system is designed to remain cautious and not enter an intersection if it is still reasoning whether the emergency vehicle is approaching the intersection based on what it is sensing.” However, it is fair to say that Cruise has felt similar things about their own vehicles’ ability to detect emergency vehicles, and Waymo has not tested in this exact situation.
The reason the Cruise vehicle did not slow earlier is unclear and Cruise has not responded to requests for comment. Human drivers don’t stop every time they hear a siren in a dense city, so it’s possible that because the car could not see the truck, nor get a good read on its direction in the echos of urban canyons that it decided it should not yet slow. In addition, at night, it is possible to notice the flashing lights of a hidden emergency vehicle reflecting off the buildings, and humans will sometimes do this, though the law does not appear to require it. Both companies declined to answer whether they pay attention to clues such as reflected lights at night.
There are also multiple systems that have been tested over the years to provide electronic warning of the approach of emergency vehicles, and in fact most new fire trucks sold are equipped with such a system, and several brands of cars receive the signals. In the future, reliable communication of this by electronic means should become normal. The initial motivation was to help the deaf, but as the world has become more computerized the systems can help in all sorts of situations.
Unanswered, however, is what Cruise means by saying that “The AV’s ability to successfully chart the emergency vehicles path was complicated” by it being on the other side of the street. Did this delay the Cruise’s braking? If this means the vehicle slowed, then decided it could go because the truck was in the right-side lane, that would put the Cruise entirely at fault in the accident, and explain the truck’s entry into the intersection. At the scene, a firefighter witness claims the Cruise vehicle “lurched.” This sentence is the most mysterious. It is unusual for Cruise to outline a failure of their prediction engine unless it contributed to the incident, but it is not explained just how it contributed. Cruise’s current statements indicate only that they braked after detecting the truck visually, though they have not disclosed how long it took to brake, though this duration does not appear to affect fault in this crash.
It’s less clear if the Fire Dept., if at fault, will need to pay for the damage. Emergency workers are given a special qualified immunity under the law which can remove this liability. That will be a subject for negotiation.
Here is the statement by the California DMV. It is not clear if this was directly in response to the fire engine crash:
Safety of the traveling public is the California DMV’s top priority. The primary focus of the DMV’s regulations is the safe operation of autonomous vehicles and safety of the public who share the road with these vehicles.
The DMV is investigating recent concerning incidents involving Cruise vehicles in San Francisco. The DMV is in contact with Cruise and law enforcement officials to determine the facts and requested Cruise to immediately reduce its active fleet of operating vehicles by 50% until the investigation is complete and Cruise takes appropriate corrective actions to improve road safety. Cruise has agreed to a 50% reduction and will have no more than 50 driverless vehicles in operation during the day and 150 driverless vehicles in operation at night.
The DMV reserves the right, following investigation of the facts, to suspend or revoke testing and/or deployment permits if there is determined to be an unreasonable risk to public safety.
- Under the legal codes, probably the fault of the fire truck.
- The Cruise vehicle, with sirens this loud, should probably have made an effort to slow upon entering the crosswalk so that, once it saw the truck, it could brake in time.
- The Fire Engine should definitely not have entered the intersection without confirming it was clear.
- The statement about the Cruise prediction being “complicated” by the path of the fire truck in the opposite lane needs clarification.
- This is not going to improve relations between Cruise and the SFFD!
To clarify about the prediction issue. A vital component of any self-driving system is the prediction engine, which attempts to estimate where everything important is going to be in the future as it moves. This in turn allows the detection of the risk of collisions. The vehicle did not properly predict (”chart the path”) the course of the fire truck. This would mean that for some time, it was not expecting it might advance into the intersection, as vehicles in the right lane normally don’t do that—except for emergency vehicles. This reduced the quality of the vehicles decisions, but Cruise has declined to disclose in what way. It is not clear what it would have done differently had it correctly made this prediction. Perhaps it would have stopped sooner. While unlikely, it could in theory also decide to accelerate to clear the intersection sooner—like speeding up at a yellow light. That stratagem might prevent a crash but robocar teams generally avoid such actions as they increase other risks.
A prediction that the fire truck will not enter the intersection is actually a valid one, since as noted such vehicles are expected to wait for traffic to clear before entering and certainly not to drive directly into a vehicle. They will often insert themselves in a hole, expecting oncoming traffic to slow and yield, but that’s not the issue here.