Experience with the Method for all-ways stop intersections has shown that a significant number of analysis conditions fall outside the range used in developing the equations used to calculate delay. These include restrictions on the percentages of right and left turns and the restriction against exclusive lanes.
Also, in some circumstances it is possible that the calculated capacity can be less than zero. TRAFFIX™ allows the user to insert any lane configuration; however, the results may be overly pessimistic if there are exclusive lanes. It is suggested that all exclusive lanes be eliminated from the analysis and that traffic from left and right exclusive lanes be added to through volumes, with a reduction factor for right turns that could turn without any conflicting flows and possibly one for left turns as well.
The minimum capacity per lane for the Four-Way Stop Method has been set at 50 vehicles per hour. The value of 50 vehicles per hour is low enough to alert the user that the volumes are outside the range of the method but high enough that an unreasonably high delay results.