People v. Lopez
In People v. Lopez, 97 P.3d 277 (Colo. App. 2004), the Colorado Court of Appeals set forth the comprehensive test for determining whether an independent intervening cause can break the chain of causation:
Three elements must be satisfied to establish an independent intervening cause sufficient to relieve a defendant of responsibility for his or her conduct:
(1) the defendant must not participate in the intervening cause;
(2) the intervening cause is one but for which the death would not have occurred;
(3) the intervening cause must not have been reasonably foreseeable.
An intervening cause is one that interrupts the natural and probable sequence of events following the defendant's acts and intervenes to cause the death.
An intervening cause destroys the causal connection between the defendant's acts and the victim's injury, thereby becoming the cause of the injury.
Simple negligence that contributes to the death of a victim is foreseeable and, as a matter of law, cannot be an independent intervening cause. However, gross negligence is unforeseeable behavior, and it may serve as an intervening cause. Gross negligence is conduct beyond simple negligence showing an extreme departure from the ordinary standard of care. (Id. at 282.)
In Lopez, the defendant was convicted of vehicular homicide for driving his car, while intoxicated, at high speed into the vehicle in which the victim was a passenger.
The defendant argued that because the driver of the car in which the victim was a passenger turned left at an intersection despite oncoming traffic, thereby placing the vehicle in the path of the defendant, the trial court erred when it failed to give an intervening cause instruction. Lopez, 97 P.3d at 278, 282.
The Lopez court rejected the defendant's argument, and held that the intervening event was foreseeable because "even if the driver made misjudgments, nothing in the record shows that her decision to turn left ... constituted an extreme departure from the ordinary standard of care sufficient to support a finding of gross negligence." Id.