Wavetronix SmartSensor 105 (SS-105) - User Guide User Manual

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INTRODUCTION

• SMARTSENSOR 105 USER GUIDE

Line of Sight – The SmartSensor is designed to work accurately in the presence of

barriers, but in general if there is an alternate mounting location that would avoid any

type of structural occlusion, this is preferred. Avoid occlusion by trees, signs, and other

roadside structures.

Neighboring Structures and Parallel Walls – It is also preferred that sensor locations

have a 30-ft. (9.1-m) lateral separation from overhead sign bridges, overpasses, tunnels,

parallel walls and parallel-parked vehicles in order to avoid multiple reflection paths

from a single vehicle.

Mounting Height – The mounting height should be based upon the offset from the

lanes of interest. For each offset, the minimum, maximum and recommended range

of heights is shown in Table 1.1, found in chapter 1. In general, the range of recom-

mended heights is between 9 and 50 ft. (2.7 to 15.2 m).

Mounting Offset – The minimum recommended offset from the edge of the first lane

of interest is 10 ft. (3 m).

Arterial Locations – Sensor sites on arterials or other roadway segments with regu-

lated stop lines should be selected at mid-block positions to increase accuracy by in-

creasing line of sight to stop-and-go vehicles.

Roadway

10 ft. min.

9 – 50 ft.

(see

mounting

guidelines)

Figure I.1 – Portable (left) and Permanent (right) Sensor Stations

Freeway Locations – SmartSensor is often used at permanent ATR stations. The

number of stations along a single roadway and the distance between stations should

be selected to achieve adequate levels of statistical confidence. Permanent ATR sta-

tions, which are selected to cover interstate, principal arterial and other national and

state highways, are used to establish seasonal adjustment factors for count data from

temporary collection sites (see Figure I.1).

Cable Lengths – Ensure that you have sufficient homerun and sensor cabling. Cable runs

as long as 600 ft. (182.9 m) using 24 VDC operation and RS-485 communications. For

longer connections, alternate wired and wireless options should be considered.