That study shows a ~1 second delay from the incursion being visible to a human to them releasing the accelerator and a further 2.3 seconds to have the brake fully depressed, by which time they were also steering. The study also implies the average human response time was adequate to avoid the collision...

To put things into perspective, the Uber spend 4 seconds after actually detecting the incursion trying to figure out whether it needed to respond and doing nothing, then a further second of enforced pause after concluding it did need to do something until finally starting to reduce speed 0.2 seconds before impact.