AARoads Forum

National Boards => General Highway Talk => Topic started by: ethanman62187 on August 31, 2011, 04:31:17 PM

Title: Weaving Interchange
Post by: ethanman62187 on August 31, 2011, 04:31:17 PM
I've been wondering about weaving. What interchange does that?  Will there be a new design to stop traffic from weaving?
Title: Re: Weaving Interchange
Post by: Ian on August 31, 2011, 04:56:19 PM
Quote from: ethanman62187 on August 31, 2011, 04:31:17 PM
I've been wondering about weaving. What interchange does that?

Cloverleaf?
Title: Re: Weaving Interchange
Post by: Quillz on August 31, 2011, 05:06:18 PM
The point of the reverse diamond interchange is to prevent weaving, right?
Title: Re: Weaving Interchange
Post by: intelati49 on August 31, 2011, 08:27:55 PM
Quote from: Quillz on August 31, 2011, 05:06:18 PM
The point of the reverse diamond interchange is to prevent weaving, right?

Not exactly. The point of a Diverging Diamond Interchange is to reduce the traffic conflict points in the intersection. :spin:

interesting note, At LOS F, All weaving segments also operate at LOS F. Anyone know why? :hmmm:
Title: Re: Weaving Interchange
Post by: Quillz on August 31, 2011, 08:49:03 PM
Ah, diverging diamond. That's what it was called, I couldn't remember the exact name.
Title: Re: Weaving Interchange
Post by: Scott5114 on September 01, 2011, 12:18:22 AM
Weaving can also occur when two interchanges of any type are placed too closely to one another. If you want an example of extreme weaving, take a  look at I-240 in Oklahoma City.
Title: Re: Weaving Interchange
Post by: agentsteel53 on September 01, 2011, 01:25:00 AM
Quote from: Scott5114 on September 01, 2011, 12:18:22 AM
Weaving can also occur when two interchanges of any type are placed too closely to one another. If you want an example of extreme weaving, take a  look at I-240 in Oklahoma City.

also, the Bayshore Freeway - US-101 between San Francisco and San Jose.  lots of weaving, with a lot of exits not yet having collector/distributor roads, especially in the Santa Clara area.
Title: Re: Weaving Interchange
Post by: roadfro on September 01, 2011, 05:35:36 AM
Quote from: Quillz on August 31, 2011, 08:49:03 PM
Ah, diverging diamond. That's what it was called, I couldn't remember the exact name.

Another term for a DDI that some states are using is "Double-Crossover Diamond Interchange". That name makes it a bit easier for the layman to understand what happens.
Title: Re: Weaving Interchange
Post by: J N Winkler on September 01, 2011, 10:32:41 AM
Weaving is not necessarily a property of interchanges.  All you need for weaving is a merge followed in short order by a diverge where entering traffic has to move out of a lane (the "weaving lane") at the same time exiting traffic has to move into the same lane.

Weaving per se is not necessarily undesirable and under certain conditions the cost, net of benefits, of eliminating weaving can be far more than tolerating it.  A standard procedure in highway capacity evaluation since at least the late 1940's has been weaving analysis, which takes into account the length of the weaving lane, the traffic volume on the road between the merge and diverge points, and the traffic volumes moving out of the weaving lane to join and moving into the weaving lane to exit.
Title: Re: Weaving Interchange
Post by: Alps on September 02, 2011, 06:42:48 PM
Quote from: intelati49 on August 31, 2011, 08:27:55 PM

interesting note, At LOS F, All weaving segments also operate at LOS F. Anyone know why? :hmmm:
Not. necessarily. true. Depends on your volume in the right two lanes. If the LOS F is caused by a downstream condition but you have a right-side exit only ramp that reduces your right-lane volume, you could get weaves at LOS D-E in a segment at LOS F. Based on HCM methodology, you can only consider one segment at a time. Therefore, your weaving segment is NOT also a freeway segment or a ramp junction. That's probably why it works that way.