## Facts

- A Yellow Cab driver left a taxi parked on a Chicago street unattended, with the engine running and the key in the ignition.
- The driver’s conduct violated Illinois Uniform Traffic Act § 92(a), requiring an unattended vehicle’s engine be stopped and the ignition locked with the key removed.
- A thief stole the cab and, while fleeing, collided with Helen C. Ney’s automobile.
- Ney sued Yellow Cab for property damage, alleging the statutory violation was evidence of negligence and a proximate cause of the collision despite the theft.
- Yellow Cab argued the thief’s criminal act was a superseding cause and that the statute was not intended to impose liability for harm caused by a thief.

## Issues

1. Whether violation of the unattended-vehicle provision of the Illinois Uniform Traffic Act constitutes actionable negligence toward a member of the public injured by a thief’s operation of the stolen vehicle.
2. Whether the thief’s intervening criminal act of stealing and driving the cab bars proximate cause as a matter of law, or instead leaves proximate cause for the factfinder based on foreseeability.

## Decision

- The Supreme Court of Illinois affirmed judgment for Ney.
- The court held the statute is a public-safety measure and its violation is prima facie evidence of negligence under Illinois law.
- The court held proximate cause was not defeated as a matter of law by the theft; reasonable persons could find the sequence of theft and collision foreseeable.
- Because foreseeability and causal connection were reasonably disputable, proximate cause was for the jury.

## Legal Principles

- Violation of a safety statute in Illinois is generally prima facie evidence of negligence, not conclusive negligence per se.
- A statutory duty aimed at public safety may define the standard of care toward persons and property foreseeably endangered by the violation.
- An intervening intentional or criminal act does not automatically sever causation; the key inquiry is whether the general type of harm was reasonably foreseeable.
- When reasonable factfinders could differ on foreseeability and causal connection, proximate cause is a question for the jury rather than a question of law.

## Conclusion

The court allowed liability for leaving a vehicle unattended with the engine running and keys in the ignition in violation of a safety statute, holding that the theft and resulting collision could be found foreseeable and that proximate cause therefore remained for the jury.


Ney v. Yellow Cab Co., 2 Ill. 2d 74, 117 N.E.2d 74 (Ill. 1954)