"Useless" C/D roads

Here's something I discovered for the first time today (OK, not really,
but it was the first time I thought about it)...."useless" C/D roads.

Usually, C/D roads (Collector/Distributor roads) are constructed where
there is a cloverleaf. There is one exit ramp off the mainline, then
the 4 ramps of the cloverleaf enter and exit from that parallel
roadway, then that road merges back onto the mainline. Its primary
purposes are to combine the exits and entrances (one exit, one
entrance, less signage on the mainline, less merges onto the mainline),
and also to keep the "weaving area" (where basically C/D road traffic
and ramp traffic "switch places" off of the mainline. This leads to
overall better mainline traffic flow. A secondary benefit is that if
the mainline is jammed, sometimes (if it is a minor interchange and not
many people know about the nature of the C/D road), one can take the
exit, bypass a bunch of traffic, and re-enter the main highway, but
that is obviously not what traffic engineers had in mind. Lets call
these people "cheaters"

Well, now think of this: a 6-ramp partial cloverleaf, with one exit
ramp and two entrance ramps, both leading onto and off of C/D roads.
The exit comes before both of the entrances. ALternatively, you can
have two exits, and then one entrance that comes after the exit. In
otherwords, no weaving. And the sole purpose for the C/D road beteen
the exit and the two entrances is for people who exit the highway and
then get right back on....aka only "cheaters" use it. My guess is that
officials designed a full C/D roadway, but traffic counts do not
require all 4 ramps at present time, however there are provisions for
building it in the future. Then there will be a weave.

So, where are there "useless" C/D roads located???

I'll start: I-95 in Maryland, both directions at Exit 85 (MD 22).

.

Relevant Pages

  • Re: "Useless" C/D roads
    ... It would the fundamental design issue in any interchange configuration ... but it was the first time I thought about it)...."useless" C/D roads. ... There is one exit ramp off the mainline, ... then that road merges back onto the mainline. ...
    (misc.transport.road)
  • Re: "Useless" C/D roads
    ... but it was the first time I thought about it)...."useless" C/D roads. ... There is one exit ramp off the mainline, ... the 4 ramps of the cloverleaf enter and exit from that parallel ... then that road merges back onto the mainline. ...
    (misc.transport.road)
  • Re: "Useless" C/D roads
    ... but it was the first time I thought about it)...."useless" C/D roads. ... There is one exit ramp off the mainline, ... the 4 ramps of the cloverleaf enter and exit from that parallel ... then that road merges back onto the mainline. ...
    (misc.transport.road)
  • Re: "Useless" C/D roads
    ... but it was the first time I thought about it)...."useless" C/D roads. ... There is one exit ramp off the mainline, ... the 4 ramps of the cloverleaf enter and exit from that parallel ... then that road merges back onto the mainline. ...
    (misc.transport.road)
  • Re: "Useless" C/D roads
    ... but it was the first time I thought about it)...."useless" C/D roads. ... There is one exit ramp off the mainline, ... the 4 ramps of the cloverleaf enter and exit from that parallel ... and ramp traffic "switch places" off of the mainline. ...
    (misc.transport.road)