  Experiments done in the early 1990's produced a surprising result: that
single photons pass through a photonic tunnel barrier with a group velocity
faster than the vacuum speed of light. Subsequent experiments with classical
pulses have also revealed apparent superluminal group velocities as well as
tunneling times that saturate with barrier length, a phenomenon known as the
Hartman effect. In this paper we show that the measured delays are in fact
cavity lifetimes as opposed to transit times. This interpretation resolves the
Hartman paradox and shows that tunneling is not superluminal as widely
believed.
