The Pennsylvania Supreme Court recently clarified two fundamental rules of traffic safety. The "assured clear distance ahead rule" requires that a driver must at all times be able to bring his or her vehicle to a stop within the distance that he or she can clearly see, or, as it is sometimes stated, "within the distance of whatever may reasonably be anticipated." Compliance with this rule requires that drivers use extra care on curves, hill crests, and narrow or winding roadways. It also requires that drivers pay careful attention to traffic and weather hazards.
The assured clear distance ahead rule sometimes conflicts with the "sudden emergency doctrine." The sudden emergency doctrine is a defense for a driver who suddenly and unexpectedly finds himself or herself confronted with a perilous situation that permits little or no opportunity to react. Where a sudden emergency confronts a driver, he or she is not expected to exercise the usual degree of care or even the best judgment. Instead, the driver experiencing a sudden emergency must only use "honest judgment." It is important to note that only those who are driving carefully and prudently are entitled to the sudden emergency defense.
In clarifying the clash between the two rules, the Pennsylvania Supreme Court recently ruled that drivers defending against negligence lawsuits are entitled to raise the sudden emergency doctrine unless there is evidence that clearly establishes that they violated the assured clear distance ahead rule.