Investigate reporting queue lengths

[dnesbitt61]

Approach is to walk forward along GPS points and identify when speed falls below a threshold. The distance from this point to the next intersection becomes the queue length. Several questions arise:

• What is the required GPS reporting frequency (time interval between locations)?
• What if no OSMLR segment is reported at the intersection where the queue begins? May end up reporting a queue length to the end of the OSMLR segment, rather than the actual intersection.
• Assumption: cannot walk backwards from an intersection and detect when speed exceeds threshold (since once the queue moves the speeds increase).
• A taxi dropping off or picking up a passenger trigger the queue length report - does this matter or is there any way to avoid it?