In today’s case (Gibson v. Matthies) the Plaintiff was operating a motorcycle travelling behind the Defendant. The Defendant brought his vehicle to a “sudden stop” prior to attempting a left hand turn. The Plaintiff was unable to react in time and rear-ended the Defendant vehicle. The Court found that the Plaintiff was negligent but also gave the Defendant 25% of the blame for his sudden stop.
http://www.ilstv.com/driver-25