Fads in highway construction

[bugo]

The US 169/BA cloverleaf is terrible.  No C/D lanes and way too much traffic at peak hours.  I dread driving through it.

[J N Winkler]

I don't see a problem with new cloverleafs as long as they meet the following two criteria:

(1) If either road is a freeway, C/D lanes are used to separate weaving movements from the freeway mainline.
(2) None of the left-turn movements have high enough traffic volumes to warrant flyover ramps.

The Creek Turnpike and Muskogee Turnpike cloverleaf meets #1, and, without looking up the data, it doesn't look like a place where #2 would be an issue.

Actually, I think Jeremy has a point on this one.  While it is true that cloverleafs have continued to be built in states other than Oklahoma (the I-95/I-74 interchange in North Carolina comes to mind), these have tended to be at rural locations and to be equipped with either true collector-distributor roadways or what I call "poor man's C/D," which is a lane added before the interchange that is dropped after the interchange and is designed to facilitate weaving.

I can't really think of any other state (with the possible exception of Minnesota) where cloverleafs are as prevalent for freeway-to-freeway interchanges and are as likely to be used in densely built-up urban areas.

A quick comparison:  the Tulsa area has 18 freeway-to-freeway interchanges, of which four are cloverleafs (five if you count US 169/I-44 with the missing link ramp), while Wichita--a much smaller metropolitan area--has 8 freeway-to-freeway interchanges, of which only one is a cloverleaf and is scheduled for upgrade to a stack/turban hybrid.

[bugo]

44/412/Creek Turnpike is a 3/4 cloverleaf if you want to count it.

[Duke87]

Cable stay bridges have become a huge fad. Seems like almost every "distinctive span" built these days is cable stay. A lot of them built in the past 20 years or so. Before then, not so much.

[hbelkins]

I can't really think of any other state (with the possible exception of Minnesota) where cloverleafs are as prevalent for freeway-to-freeway interchanges and are as likely to be used in densely built-up urban areas.

Massachusetts seems to have a lot of them, especially on the I-495 corridor.

[cbeach40]

True, but snow plows tend to tear up pavement markings, especially large ones like route shields.

Thermoplast markings (which most southern states tend to use), yes.  Paint, no.

Maybe not "tear up" but certainly "wear out" is applicable. Running winter maintenance equipment and dropping material on pavement markings tends to leave them pretty illegible come spring.

Another consideration for symbol marking is that painting within a lane, especially a freeway lane, is a very expensive operation. It's one thing to have a mobile operation where the machine constantly is moving to stripes the road. But to stop and put down a stencil - especially multiple stencils for several different colours - will require a lot more intensive/expensive traffic protection plan. Again, the advantage for jurisdictions with longer life expectancy for their paint where they need not do that as often.

[jeffandnicole]

Even place that get a lot of snow have clear roads 360 days out of the year.  It's the rare snowstorm that leaves roads snowcovered more than a day.

True, but snow plows tend to tear up pavement markings, especially large ones like route shields.

Nah.  If that was the case, solid and passing lines would be scraped up every winter, would barely be visible come spring, and would need to be repainted quickly every year.

It doesn't happen. 

[hbelkins]

I've often wondered why stop bars and crosswalks seem to be done most often via thermoplastic pavement markings instead of painting. Are there reflectivity issues?

[J N Winkler]

I can't really think of any other state (with the possible exception of Minnesota) where cloverleafs are as prevalent for freeway-to-freeway interchanges and are as likely to be used in densely built-up urban areas.

Massachusetts seems to have a lot of them, especially on the I-495 corridor.

This is a good point--I count nine "pure" cloverleafs on Massachusetts I-495, not including a couple of "impacted" cloverleafs (link ramps missing, at least one loop unrolled) at the closely spaced US 3 and Lowell Connector interchanges.  But most of the locations in which they are used appear to be pretty rural.

I also seem to remember a MTR thread some years ago in which it was argued that stacks were rare in northern states because of the greater prevalence of bridge icing in the winter.  This proposition is not actually true since the northern states do have a considerable number of stacks; it is Texas (with more than 25--about half the US total and far more than any other country in the world) that is the true outlier on a global basis.  The states that have land or water borders with Canada actually have more stacks than California (by my count, 10 in California versus a total of 11, consisting of 3 in NY, 3 in OH, 4 in MI, and 1 in WA).

However, a more refined version of the bridge icing argument would lead us to expect interchange forms with lesser structural content to be more prevalent, given similar traffic levels and location, in the northern states than elsewhere, and cloverleafs as well as some forms of directional interchange would therefore be favored.

[cbeach40]

I've often wondered why stop bars and crosswalks seem to be done most often via thermoplastic pavement markings instead of painting. Are there reflectivity issues?

Thermoplatic has greater durability, but more expensive to install. So cases like those where it's a more difficult location or complicated design there's advantages to using the more expensive material but doing so less often.

In terms of durability of paint lane markings in an area with extensive winter maintenance, the target service life per the Ontario Traffic Manual is 6-12 months for a typical roadway, a very high volume road it can be as low as 3 months.

[corco]

Even place that get a lot of snow have clear roads 360 days out of the year.  It's the rare snowstorm that leaves roads snowcovered more than a day.

Bahahaha, you haven't spent much time in the west in the winter have you? We don't use salt out here and leave even major roads snowpacked with sand on them as a matter of course. The town I live in in Montana doesn't even own a plow. That's why there is still a healthy market for studded tires, and those do damage paint.

[PHLBOS]

Massachusetts seems to have a lot of them, especially on the I-495 corridor.

This is a good point--I count nine "pure" cloverleafs on Massachusetts I-495, not including a couple of "impacted" cloverleafs (link ramps missing, at least one loop unrolled) at the closely spaced US 3 and Lowell Connector interchanges.  But most of the locations in which they are used appear to be pretty rural.

I-95 in MA has a total of 13 "pure" full cloverleafs; three of them south of Canton (I-93) and the other 10 are along the 128 corridor (Peabody to Canton).

Two of the older, tighter cloverleafs along MA 128 in Danvers (MA 35 & MA 62) were just recently converted into diamond interchanges.

MA 24 has a total of 8 full cloverleafs.

[vdeane]

Even place that get a lot of snow have clear roads 360 days out of the year.  It's the rare snowstorm that leaves roads snowcovered more than a day.

Bahahaha, you haven't spent much time in the west in the winter have you? We don't use salt out here and leave even major roads snowpacked with sand on them as a matter of course. The town I live in in Montana doesn't even own a plow. That's why there is still a healthy market for studded tires, and those do damage paint.

Perhaps "states without bare pavement policies" would be a better way to phrase that.  NY is the snow capital of the northeast and still has the paint visible most days in winter.

[agentsteel53]

Button copy was undeniably a fad.

nope.  discrete reflector elements can be traced back to ~1929 in the US, and they lasted until 2002.  for many iterations of technological improvement, discrete circular elements won out.  reflective glass panes (1920s) gave way to circular cateye reflectors by the early 30s.  then, technological improvement resulted in the more cost-effective Stimsonite (Lucite plastic) to replace glass by the 1940s.

Stimsonite buttons lasted so long (well into the 80s in the majority of states, so that's ~50 years of design use) because they were brighter than all contemporary retroreflective sheeting options.  the vast areas of background black (and later, green) were deemed not necessary to illuminate, so having buttons on the foreground was sufficient. 

it really wasn't until a few refinements of honeycomb sheeting (late 80s, really) that button copy was functionally obsolete.  in certain applications (white text on dark background), it was clearly better than the older engineer grade (or, heaven forbid, silver Scotchlite or even beaded glass paint) sheeting.  then 1970s honeycomb was notoriously fragile, falling apart within 5-6 years.  only in the late 80s, early 90s (about the same time that diamond grade was developed) did honeycomb reach a level of functionality that allowed it to universally replace button copy. 

a lot of places had gone away from button copy years before for short-term cost reasons, but some places invariably went back because the buttons worked.  Washington, for example, had retroreflective sheeting overhead signs in the late 50s and mid-60s, then went to button copy for several decades before returning to retroreflective sheeting.

even the holdouts (California, Ohio, Arizona) insisted on button copy because the stuff worked; it was just no longer feasible to manufacture letter forms for only three states, so AGA pulled the product.

[SSOWorld]

So Arizona switched to Clearview and California doesn't replace signs

LED Lamp posts are slowly working their way in.  When I left WI in May 2013 for the 6-month ride, nowhere in WI did LED posts exist.  When I returned, I saw them in at least 3 locations - including the Madison area.

[lepidopteran]

Don't forget that the new interchange on I-95 at the ICC (MD-200) is a full cloverleaf.  It does, however, have a flyover duplicating the EB->NB movement.  The loop it duplicates is used to access C/D-lanes (when they open) and the next two exits downstream (one of which is still under construction).  The flyover just "braids" right over them.  There is also a C/D road on the SB side of I-95, yet that's undercut by a direct exit ramp from I-95.  Someone was trying to make darn sure there'd be no weaving!

(The "flyover" is more of a mixing-bowl-type ramp due to the interchange's sprawl -- what's the official name for that?)

[DaBigE]

So Arizona switched to Clearview and California doesn't replace signs

LED Lamp posts are slowly working their way in.  When I left WI in May 2013 for the 6-month ride, nowhere in WI did LED posts exist.  When I returned, I saw them in at least 3 locations - including the Madison area.

They've been in the Madison-area before 2013. The last phase of the E Washington Ave (US 151) reconstruction put them in along Wis 30 at the interchange with US 151. That was around 2009/2010. I believe that was the/one of the first test sites for WisDOT.

[J N Winkler]

So Arizona switched to Clearview and California doesn't replace signs

In Arizona it was not a smooth transition from button copy to Clearview.  The last major Arizona DOT signing contract with button copy (per Richard Moeur's "Farewell to button copy" post in MTR on December 17, 2000) was the I-17 Maricopa TI to Thomas Road sign update then in progress (TRACS H480501C).  ADOT then used demountable Series E Modified prior to the transition to Clearview, which started with the I-10 Poston Road to Hovatter sign rehabilitation contract (TRACS H646001C) in 2006.  There was actually a fair amount of urban sign replacement work that was done with reflective-sheeting Series E Modified instead of Clearview, as well as new lengths of the Loops, the I-10/I-19 Crossroads upgrade, etc.

[mgk920]

So Arizona switched to Clearview and California doesn't replace signs

LED Lamp posts are slowly working their way in.  When I left WI in May 2013 for the 6-month ride, nowhere in WI did LED posts exist.  When I returned, I saw them in at least 3 locations - including the Madison area.

The City of Columbus, WI changed all of their streetlights to LEDs at least two years ago - the whole city was using those fixtures when I visited a friend there in March of 2012.

Appleton installed several hundred LED streetlights, mainly at major intersections and on a couple of bridges, as well as on sections of several downtown side streets, later on in 2012.

Mike

[Quillz]

Forgive my ignorance, what is SPUI?

And I don't know if I would call roundabouts/traffic circles a "fad," but a street near my house just had every single intersection redone as a traffic circle. And given that we're talking about a small neighborhood street, it seemed a bit unnecessary.

[hotdogPi]

Forgive my ignorance, what is SPUI?

It stands for Single Point Urban Interchange.