This document describes techniques and systems to alternate power-level scanning for ToF lidar systems. The described lidar system transmits an initial signal having a first power level of an alternating pattern of power levels. The initial signal is associated with an initial pixel of consecutive pixels. The lidar system then transmits a subsequent signal, which is associated with a subsequent pixel of the consecutive pixels, having a second power level. The transmission of the initial signal and the subsequent signal with the alternating pattern of power levels limits a total power level emitted by the lidar system during a time interval to comply with safety regulations. The alternating pattern of power levels also permits the lidar system to switch between a long-detection range and a short-detection range for consecutive pixels.