Traffic counts for intersection approaches are normally made

Traffic counts for intersection approaches are normally made at the stopline, because that allows the counter to see which way the traffic is turning. However, for approaches that are oversaturated (i.e., the queue does not disappear during the green phase), a count made at the stopline is misleading.
a.For an approach in which the queue does not dissipate, if a stopline count isn’t really measuring arriving volume, what is it measuring?
b.How should turning movement counts made at a stopline be adjusted to properly measure arrival volume for an approach whose queue does not dissipate?

Solution

a)There are many way to do the traffic count can be done manually or can be done with instrument like pneumatic hose(in this device the count is done due to the impulse that is generated when traffic is passing over it) , in any case the obesever or the instrument is not measuring the traffic volume but the no of axle that is passing the considerd stopline.

b)First of all the stopline should never be too close to the location where the vehicles can turn easily as this leads to error in the reading as there will be many vehicles that is turning.There should be a very careful observations that is for the vehicles that is turning and the location for their turning because if the vehicle is turning just after the rear axle of the vehicle is crossed the reading should be deducted by one only as there will be only one extra reading from the correct value.