Almost certainly not, unfortunately:1) The settlement agreement almost certainly contained language that it was in settlement of all claims; such language is common and enforceable.2) Even without such language, the law generally requires all claims arising out of a single accident or event to be brought at the same time, and precludes a person (such as under the doctrine of "res judicata") from later bringing another lawsuit about the same matter.3) The statute of limitations, or time to bring a lawsuit, in your state for injuries from a car accident is only three years, so it also appears to be too late to bring another claim.