Evaluation Of Milwaukee B And Synchronized Interchanges

[tradephoric]

A recent study out of Wayne State University evaluates two new service interchange designs (Milwaukee B and Synchronized).  The new interchanges were compared to 4 existing interchange designs (Diamond, DDI, Parclo B, and Milwaukee A).

Evaluation Of Milwaukee B And Synchronized As New Service Interchange Designs
https://digitalcommons.wayne.edu/cgi/viewcontent.cgi?article=2844&context=oa_dissertations

[tradephoric]

It's apparent that the Milwaukee B performed the best in this study when looking at mean travel time.  The synchronized interchange had relatively low travel times for every direction except for "left turn from freeway to arterial".  The study does state that the 'synchronized intersection provided great performance when the through traffic was the dominant traffic volume in the interchange.  In this condition, the travel time of the synchronized interchange was 20% lower on average than the DDI and 27% lower than the diamond'.

[kphoger]

It appears Milwaukee A performed decently well in that pack.  But, to my eyes, it just looks like a ParClo A4 with its loop ramps unraveled a bit.

[tradephoric]

Yeah i don't see much operational advantage to the Milwaukee A over the Parclo A4 other than the fact that loop traffic entering the freeway doesn't have to back track so far down the arterial before entering the loop (total distance traveled for that movement should be slightly less).  Here is a real world example of the Milwaukee A:


https://www.google.com/maps?ll=42.96285,-87.94907&z=17&t=h

[johndoe]

In a Parclo A drivers making a "left" onto the freeway typically have to go through a signal at the first ramp intersection.  At the Milw. A it's only a right turn, so easier signal timing.

[tradephoric]

In a Parclo A drivers making a "left" onto the freeway typically have to go through a signal at the first ramp intersection.  At the Milw. A it's only a right turn, so easier signal timing.

That's a very good point John, i completely missed that.  At the 27th Street Milwaukee A interchange traffic entering the freeway doesn't pass under any interchange traffic signals.  That's a big benefit.   

[tradephoric]

Here is a Synchro model of the Synchronized Interchange.  This can be an efficient interchange design when there is low to moderate 'left turn from freeway to arterial' traffic. 

https://youtu.be/W01GG3l58vg

EDIT:  Ideally traffic volumes along the Michigan left turnarounds would be light enough that they could be unsignalized.  This would reduce delays for traffic on the arterial who are getting on the freeway.  Here's a real world example of an unsignalized Michigan left crossover servicing an interchange off-ramp:  https://www.google.com/maps/@42.55847,-83.13006,651m/data=!3m1!1e3