Guardrails And Barriers; Sunken Road And Roadside Walls - Image Sensing Systems RTMS Echo User Manual

Chapter 2:

Guardrails and Barriers

Sunken Road and Roadside Walls

RTMS Echo User Guide
In almost all cases, median guard-rails or barriers do not interfere with traffic
detection. In the few cases in which such interference may occur, e.g., large
metal barrier, very tall barriers or movable metal fences, a good solution is to
use a second sensor on the other side of the road. Each of the sensors can
monitor lanes on its side of the barrier, requiring a smaller setback to cover
fewer lanes, as shown below.
Figure 2-10: Two-Sided Placement
When vertical surfaces reflecting microwaves (e.g., dense chain link fences or
retaining walls of a sunken roadway) are present, multi-path reflections from
large vehicles in close lanes cause additional false (ghost) detection in farther
detection zones.
Figure 2-11: False Target Generated by Fence Or Wall
To avoid this problem install the RTMS Echo higher and increase the elevation
angle to detect the far lanes of traffic excluding the nearest lanes, as shown on
the right in Figure 2-11.
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Pre-Installation Considerations
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