If you are injured in a car accident in New York, the compensation available under your no-fault policy may not seem like enough to cover your losses. However, if your injury is considered “serious,” you may be able to file a lawsuit against the at-fault driver. The 90/180-day rule is one of the ways it is possible to meet the state requirements for a “serious injury.” If an individual is substantially unable to carry out all of their usual daily activities for at least 90 of the 180 days immediately following the injury, they are considered disabled. However, proving this is not easy.