Signalized Intersections

[maximus808]

when finding the effective green time,

g=G+Y-tl, where G=total green time, Y=yellow plus all red, and tl=total lost time=clearance lost time plus start up lost time.

I'm doing a problem where it has the following for lost clearance time, tl=yellow plus all red minus encroachment of vehicles into yellow and all red (2s default)

My question is do we always need to account for this 2s default? Thanks.

 

[Ambrug20]

when finding the effective green time,g=G+Y-tl, where G=total green time, Y=yellow plus all red, and tl=total lost time=clearance lost time plus start up lost time.

I'm doing a problem where it has the following for lost clearance time, tl=yellow plus all red minus encroachment of vehicles into yellow and all red (2s default)

My question is do we always need to account for this 2s default? Thanks.

I know for sure that for pedestrian lost time is 4 sec. For drivers, I am not sure, but I found in HCM p.16-109 said use 2 sec for lost-time. I am not sure if its a default, but it safe to use, I gess.

 

[St_Kentucky]

This is often the assumed value. In practice, jurisdictions may make another assumption based on observed driver behavior in the area.

 

[Vishal]

For the purpose of the exam, you will be provided this value. Total lost time used in the analysis is different for jurisdictions - 2 seconds is commonly used, but I have had to use 3 seconds for one particular agency (claiming that there are more elderly drivers). Hope this answers your question.

 

[aucivileng]

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