1. A method for optimizing object detection performed by autonomous vehicles, the method comprising: receiving, by one or more computing devices having one or more processors, sensor data captured by a sensor of an autonomous vehicle, wherein the sensor data includes a first object labels applied by the autonomous vehicle, each of the first object labels corresponding to a computed speed of a particular object of the sensor data; receiving, by the one or more computing devices, a one or more second object labels not applied by the autonomous vehicle for the sensor data corresponding to a computed speed of the particular object; determining, by the one or more computing devices, differences in speed between corresponding objects of the first object labels and one or more second object labels; determining, by the one or more computing devices, a number and value of differences in speed based on the determined differences; and generating, by the one or more computing devices, a recommendation for an adjustment of at least one object detection parameter of at least one of a plurality of sensors based on the determined number and value of differences in speed in order to optimize object detection.