My recent zig-zag trip across northern Missouri took me (in small part) near Warrensburg. I was westbound on US-50 from Sedalia, exited at MO-13 east of town, headed south toward Clinton.
The interchange there has a couple of interesting features. Neither is very notable by itself; it is the combination that caught my attention. The most obvious is the pair of traffic circles (or roundabouts, or whatever) where the ramps intersect the state highway. This is not new or exotic or noteworthy. By now we should all be familiar with the concept.
The other feature is perhaps a few years older. When this interchange was constructed, MO-13 was envisioned as a divided highway, two lanes in each direction. The bridge carrying US-50 over MO-13 was built with that contingency in mind, space for the second (southbound) carriageway provided for. This, too, is not particularly unusual. Transportation planners should anticipate and provide for future needs.
I wondered, though, if the latter feature might have negated the need for the earlier one, at least temporarily. Do the traffic circles preempt the need for the second carriageway? Will they handle the future volume efficiently enough to head off such a future need?
There are lots of "ghost ramps" to never-built highway interchanges. Do we have a term for similar segments of never-built non-ramp facilities?
Ghost bridge?
Planning ahead?
Quote from: brianreynolds on September 16, 2013, 10:35:22 PMI wondered, though, if the latter feature might have negated the need for the earlier one, at least temporarily. Do the traffic circles preempt the need for the second carriageway? Will they handle the future volume efficiently enough to head off such a future need?
I don't think so. The future decision to expand SR 13 to four-lane divided, if it ever occurs, will likely be made at the corridor level, and will not be influenced by traffic load at the ramp termini at this interchange.
QuoteThere are lots of "ghost ramps" to never-built highway interchanges. Do we have a term for similar segments of never-built non-ramp facilities?
I think this is covered by the term "phased construction."