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VIDBE-Q Volume 63 Issue 4
Current Development Status
An initial PedPal prototype app has been developed that provides the basic
ability to orient the pedestrian at a given intersection and to communicate crossing
direction and required crossing duration. The mobile app runs on an iPhone 8 that is
attached to an Arada Locomate ME DSRC "sleeve" (shown in Figure 2)
The DSRC sleeve transmits and receives messages to/from a DSRC Road Side Unit
(RSU) mounted at the intersection and
communicates with the smartphone via
Bluetooth. As the pedestrian approaches an
equipped intersection, it first interprets the
MAP message being broadcast by the RSU
to obtain information about the geometry of
the intersection, and then subsequently uses
SPaT (Signal Phase and Timing) messages generated by surtrac to provide phase
countdown information in different crossing directions to the pedestrian. The mobile app
transmits a SRM (Signal Request Message) to surtrac specifying how much time is
required to cross, once the pedestrian indicates which direction he/she would like to
cross. surtrac replies with a SSM (Signal Status Message) indicating whether the
extended crossing duration has been granted, or whether the pedestrian should wait for
the next green cycle.
Fig. 2: Locomate ME sleeve with iPhone
