The Cruise test mule was a 2016 Chevy Bolt EV, operating in fully autonomous mode with a test driver, Manuel DeJesus Salazar in the driver's seat . According to GM’s disengagement report, it was traveling in the center lane at 12 miles per hour, when…
“Identifying a space between two vehicles (a minivan in front and a sedan behind) in the left lane, the Cruise AV began to merge into that lane. At the same time, the minivan decelerated. Sensing that its gap was closing, the Cruise AV stopped maldng [sic] its lane change and returned fully to the center lane.”
While that was happening, Oscar Nilsson was filtering up through the Oak Street traffic at about 17 miles per hour. Oscar was riding a stylish 1969 Honda S90. He was ‘lane-splitting’ or filtering between lanes 2 & 3, i.e. approaching the Bolt from the right rear.
When the Chevy began moving to the left, Oscar also tracked forward and left – as you would when filtering to optimize the distance between vehicles. He moved into the space vacated by the Bolt.
It would be reasonable–and indeed a motorcycle safety ‘best practice’–to accelerate into that vacated space. For safety reasons a filtering motorcyclist always needs to be aware that any new gap can be seen as an opportunity for surrounding car drivers. It’s safer to be in that gap and ideally abreast of adjacent autos, rather than in the traffic seam, between that gap and a potentially inattentive driver.
But in this instance, when the CAV ‘changed its mind’ and “re-centered” in the middle lane, it sideswiped Nilsson.
This is where things get interesting.
Apparently, as reported in Traffic Collision Report #l70989746, the motorcyclist was determined to be at fault for attempting to overtake and pass another vehicle on the right under conditions that did not permit that movement in safety in violation of CVC 21755(a). (“The driver of a vehicle may overtake and pass another vehicle upon the right only under conditions permitting that movement in safety. In no event shall that movement be made by driving off the paved or main-traveled portion of the roadway.”)
Most California motorcyclists would not consider Mr. Nilsson’s maneuver to be an overtake. Although lane-splitting was legally defined in California in 2016, the practice continues to exist in a gray area. According to the California DMV…
California law does not allow or prohibit motorcycles from passing other vehicles proceeding in the same direction within the same lane, a practice often called "lane splitting," "lane sharing" or "filtering."
I traded emails with Sergei Lemberg, Mr. Nilsson’s lawyer, who wrote...
“Absolutely nothing prohibits safe and reasonable lane splitting at present. We believe the GM car was at fault, veering into and hitting Mr. Nilsson. The operator of the GM vehicle states in the police report that he saw Mr. Nilsson before the collision, but didn't have enough time to grab the wheel. The maneuver by the autonomous car was unpredictable and dangerous.”
It seems to me that the lawsuit, if it comes to trial, will hinge on a question of fact: Was Nilsson making an unsafe pass, or was he lane-splitting in a manner long accepted in California–which might mean the Cruise AV was at fault when it returned to its lane?
An alert human driver in that situation should have realized that when he started to vacate his lane position, another vehicle might move into it.
Considering Mr. Nilsson’s slow closing speed, a skilled human driver checking rear view mirrors every few seconds would likely have been aware of Mr. Nilsson’s approach in the 2-3 seam–but even if the driver was not aware of Mr. Nilsson, any vehicle in Lane 3 might have decided to move into Lane 2. If I got part way through a lane change to the left and suddenly changed my mind and decided to abort that maneuver, I would definitely throw a right-side shoulder check before moving back.
At the very least, the fact that the Cruise AV moved back into a space occupied by a full-sized person and a Honda S90 suggests an inadequacy in the Bolt’s sensor package. And Cruise got a valuable data point on the behavior of filtering motorcycles.
It’s interesting to speculate on whether, if this lawsuit goes to trial, GM will attempt to present video evidence from the Cruise AV. I imagine such video exists (and I would love to hear from anyone who can confirm my guess that it does.)
I ride motorcycles in California quite often. Frankly, I’m a little worried about a well-funded and motivated defendant (GM) establishing a precedent that would more strictly define lane-splitting and the conditions if any when it should be allowed. In fact, I’m a little worried that AV companies will put pressure on California to come into line with other states and ban the practice. The reason GM shouldn’t do that is simple: lane-splitting is an accepted and fully legal practice in the rest of the world. We motorcyclists enjoy the right to filter and AVs need to be able to safely deal with us.