Which of the following is NOT a speed measuring instrument?

The reasoning for identifying the camera as not being a speed measuring instrument hinges on the fact that cameras themselves do not directly measure speed. While some traffic enforcement systems integrate cameras with speed measurement technologies, such as RADAR or LIDAR, the camera's primary function is often to capture images or video for documentation of traffic situations, violations, or accidents.

In contrast, RADAR and LIDAR are specifically designed to measure the speed of vehicles using electromagnetic waves and laser technology, respectively. Time distance computers can also calculate speed based on the time taken for a vehicle to travel between two known points. Therefore, while cameras play a supporting role in traffic enforcement and can work with speed measurement technologies, they do not directly measure vehicle speed.