Wrongful death

Hi, My sister died in a motorcycle accident last year. She was the passenger on the motorcycle; they were driving down the road (was later determined by the police that the person driving the motorcycle was speeding) however, they were hit by a vehicle that was making a left hand turn from the suicide lane and claimed that they did not hear or see the motorcycle; witnesses said that the driver of the car was trying to beat traffic by cutting the turn. After waiting a few months to finally get the police report, they apparently determined that the woman driving the car was not at fault. My question: Do we have any legal standing to file a wrongful death lawsuit against the driver of the car that hit and killed my sister and the driver of the motorcycle? My sister left behind two kids, ages 16 and 19 now; 15 and 18 at the time of her death. The woman is trying to settle with us but we want to know all our rights, as we were told that we had no grounds to file such a suit against her. Thank you!