The Chicago Transit Authority, Metra and Pace are not insurers of the absolute safety of their Chicagoland passengers. But they do have a duty to exercise the highest degree of care consistent with the practical operation of their buses and trains to protect their passengers.
A rebuttable presumption of negligence is raised against a common carrier when a plaintiff shows that she was a passenger, an accident happened with a vehicle wholly under the control of the common carrier and that an injury was inflicted. Once that presumption is raised, the carrier must explain why the accident resulted from a cause for which it should not be held responsible.
Some of the factors that may be considered include the weather, road conditions, the speed of the vehicle and the actions of other parties involved in the accident.