Phasing plan synthesis: 

The phasing plan is synthesized based on the left turn protection established in the first step. Unlike the full operational analysis procedure, which allows virtually any practical phasing scheme, the quick estimation method considers only the most common schemes in which all left turns lead the through movements in the same direction. The existence of a left turn phase only for southbound traffic leads to the following phasing plan shown in the table:

  • East-west through (EBWBTH)

  • SB through and left (SBTHLT)

  • North-south through (NBSBTH)

The above terminology does not recognize the right turn in the phasing scheme. Within the computations, the right turn is recognized as a movement competing for green time only in the sense that the right turning volumes will be used in place of the through volumes if the right turning volume per lane is higher than the through volume per lane. The quick estimation method assumes a simple phasing in which the right turn proceeds concurrently with the through movement. That assumption is valid for purposes of this example. Another example will be considered later (sub-problem 6d) in which the right turn volume must be reduced to account for vehicles moving on an exclusive right turn phase. It is, however, important to note that extremely complex phasing may not be amenable to the simplifying assumptions of the quick estimation method, and situations will occur in which the full operational method will be strongly preferred.