Simple solution to weaving at cloverleafs?

[tradephoric]

MDOT is in the process of redesigning a full cloverleaf interchange at I-75 & Holland Road near Saginaw.  Here's a link to the project report:

https://www.michigan.gov/documents/mdot/MDOT_I-75_Widening_in_Saginaw_County_Environmental_Assessment_422371_7.pdf

After considering many interchange designs (including the SPUI and DDI), MDOT settled on a Parclo AB, 4 quadrant interchange as the preferred alternative.  My idea was instead of eliminating the loop ramps just extend them out to limit the effects of weaving.  Some additional ROW would need to be acquired to fit the extended ramps, but the advantage is you don't have to construct (and maintain) two-traffic signals along Holland Road.
https://www.youtube.com/watch?v=Rt2Xv_mtU2E
https://www.youtube.com/watch?v=FsD_4q0snCA

An example of an extended cloverleaf interchange can be seen on I-95 outside of Richmond, Virginia. 

https://maps.google.com/maps?ll=37.35387,-77.404304&spn=0.014055,0.013626&t=h&z=16

[NE2]

How does that solve weaving?

[tradephoric]

How does that solve weaving?

The theory is that the crash rate at a cloverleaf would decrease as the weaving length increases.  Of course the theory might be bunk.  Doing more research and stumbled onto this:

Fazio, Holden, and Rouphail (1993) concluded that weaving sections with shorter lengths (500 ft. or less) have higher conflicts but lower crash rates.

http://www.urbanmobilityindia.in/Upload/Conference/bfdeb08c-143c-462a-84f4-8722895ba389.pdf

[johndoe]

Interesting.  I always wondered why more entities don't do the "escape" lane at full cloverleafs.  See the second drawing here: ftp://ftp2.dot.state.mn.us/pub/outbound/ocic/BMOC/DESIGN_INFO/BR%208929%20%28Dobbins%20Creek%29/SP%205080-150_DOBBINS%20CREEK_DRAFT%20PLAN/084-104516_SS_TYPICALS-SS8.pdf

It could be done at any cloverleaf at a relatively low price as a way to increase your weaving length.  You just have to end the taper before the next ramp merges, which is usually just as long as the distance between the loops.  You'd double the opportunity for those people to merge.

[TheHighwayMan3561]

MNDot has more recently added "auxiliary" taper lanes through the cloverleaf that keeps through traffic out of the exit/entry areas while saving money on building full C/D lanes.