California law gives bicyclist and pedestrians the "right of way" which means generally speaking, other motorists (those who drive a motor vehicle on California roads, streets and highways) owe a duty of good faith to watch out for them whenever possible. However, the law of apportionment can apply which shifts liability between the motorist and injured bicyclist or pedestrian when the facts support such a shift. For example, sometimes a pedestrian is not walking squarely in a crosswalk or is jaywalking; however, this act on the part of the pedestrian does not eliminate the duty of the motorist to be mindful of this sometimes happening.
More importantly, since jay walkers are "foreseeable" (meaning it can happen, or there exists a possibility of it happening), it should be known by the average person or motorist. At the same time, it should be foreseeable to the average person who engages in jay walking that motorists may not see them as well had they been in a properly marked cross walk. California law imposes this foreseeable circumstance on both the motorist and the person jay walking which can lead both motorist and jaywalker to split liability equally, or in apportionment (ratio) to their respective negligence.
Injury documentation is very important with bicycle or person/pedestrian versus auto accidents as the injuries to a bicyclist or pedestrian can be grave. Obviously, such persons have less protection to prevent serious injuries. This is also why evidence documentation is extremely crucial and time is of the essence to gather and confirm all evidence. Photographs, witness statements, and police reports are very important, as well as preservation of property damage to the bicycle and automobile which can sometimes help explain position of impact from the accident.