TR Circular E-C058_9th LRT Conference_2003.pdf - Florida ...

Koonce, Urbanik, and Mishra 181
FIGURE 3 Signal priority communication paths (concept of operations).
At the most basic level, the LRV must be detected by the control system and the traffic
signal must accept the request for priority. The proposed monitoring system will be established
to allow the MTA to receive automated reports related to the operations of the signal system and
its LRVs along the Howard Street corridor.
Existing System
The existing system uses a Wayside Detector Unit at each intersection that can receive
preemption requests from the LRV and the calls can be placed on an intersection-by-intersection
basis. Once a LRT vehicle departs a station, the LRV can send a request that triggers a message
at the first intersection as a request for service at a particular “time service desired” (TSD). This
call is serviced by a cascading call in an attempt to reach the 2 to 5 intersections downstream of
the initial intersection. The preemption occurs throughout the intersections between the departing
station and the next station in a routine that reduces the chance that the vehicle may stop between
stations.
Proposed System
The proposed concept of operations is to provide separate TSD requests at each intersection.
This provides more flexibility in the ability of individual intersections to respond to the priority