What is the primary evidence in speed detection?

The primary evidence in speed detection is visual estimation. This is the initial observation made by law enforcement officers before any technological tools are utilized. Officers are trained to visually estimate the speed of vehicles based on their experience and understanding of traffic patterns.

Visual estimation is crucial because it provides context to the enforcement action. For example, an officer may observe a vehicle moving conspicuously faster than the flow of traffic, which raises suspicion. This observational skill lays the groundwork for further investigation with speed detection devices, such as RADAR or laser technology.

While RADAR and laser readings provide quantifiable measurements of speed, they are often considered secondary to the officer's visual assessment. This initial observation helps to establish reasonable suspicion or probable cause when deciding to use these tools. In some jurisdictions or situations, visual estimation alone may even be sufficient for initiating a stop if the behavior of the vehicle fully supports the officer’s judgment.

Witness statements can corroborate an officer’s visual estimation but are not considered primary measurement tools in speed detection. Similarly, while RADAR and laser readings are accurate and reliable evidence, they depend on the initial observational context set by the officer's visual estimation.