  We present a Floquet scattering theory of electron waiting time distributions
in periodically driven quantum conductors. We employ a second-quantized
formulation that allows us to relate the waiting time distribution to the
Floquet scattering matrix of the system. As an application we evaluate the
electron waiting times for a quantum point contact, modulating either the
applied voltage (external driving) or the transmission probability (internal
driving) periodically in time. Lorentzian-shaped voltage pulses are of
particular interest as they lead to the emission of clean single-particle
excitations as recently demonstrated experimentally. The distributions of
waiting times provide us with a detailed characterization of the dynamical
properties of the quantum-coherent conductor in addition to what can be
obtained from the shot noise or the full counting statistics.
