When the antenna is aimed across the roadway at an angle to the target vehicle, which error can be observed?

When the antenna is aimed across the roadway at an angle to the target vehicle, cosine error is observed. This type of error occurs due to the geometric relationship between the angle of incidence and the actual speed of the target vehicle.

When the radar or lidar device points at an angle rather than directly perpendicular to the vehicle's path, the speed that is measured becomes affected by the cosine of that angle. The radar/Lidar measures the relative speed of the vehicle based on the direct line of sight, and when this line deviates from the true path of travel, it produces a calculated speed that is lower than what the vehicle is actually traveling.

This means that if the angle is significantly off, the measurement can misrepresent the actual speed, leading to potential inaccuracies in enforcement or reporting. Understanding this error is crucial for operators to correctly interpret the readings and take appropriate action.

In this scenario, the measurement may not reflect the true speed because it diminishes based on the angle's cosine factor, thereby highlighting the importance of properly aligning the detection equipment.