At its core, liability means responsibility. Liability must be determined in a personal injury lawsuit, and another party or entity must be at fault. For example, if you are riding a motorcycle on the freeway and a larger vehicle merges into your lane without looking, resulting in a collision that throws you off your bike, the driver of that large vehicle is liable for your damages. Liability can be difficult to determine, and it will be helpful for you to have an attorney on your side helping to prove your case.