CHAPTER 7 CHANNELS-ALERTS-ZONES 69
Channel 1
Level 1
Level 2
Queue
Clearance
Figure 7.5 – Priority Channel Zones
e rst two zones work in tandem to allow you to provide dierent levels of dilemma zone
protection based upon the discovery range of each vehicle. Vehicles discovered upstream of
the discovery range threshold are classied as level one priority and are given the highest
level of protection. Vehicles discovered downstream of the discovery range threshold are
classied as level two priority and are given a reduced but adequate level of protection.
Note
Priority channels are only available with SmartSensor Advance Extended Range. The
extended range of the sensor is best matched to:
• Distinguish between large vehicles (trucks and buses) and small vehicles (pas-
senger cars).
• Provide dilemma zone protection for large vehicles. Trucks have been shown to
have dilemma zones a far back as 7.5 seconds. For example, an ETA of 7.5 sec-
onds at 65 mph is equivalent to 715 ft. (217.9 m). This is beyond the range of
SmartSensor Advance, but not SmartSensor Advance Extended Range.
By default the discovery range threshold is set at 750 feet. If necessary, adjust the discovery
range threshold so that most large vehicles are discovered beyond this threshold and most
small vehicles are discovered after it.
To Next Page
Loading...
