TX: I-35 Proposed Improvements Denton to FM 3002 in Cooke Co

[CtrlAltDel]

It is desirable not to have broken-back curves at all, and straightening the big curve so that it has a radius of at least 2765 ft (corresponding to curvature of 2° or less) would likely reduce accidents

This was a very interesting post, but it did raise some questions with me.

If anyone knows, how are broken-back curves problematic? Is there a certain distance where a broken-back curve becomes just two curves? And how is radius related to curvature? I can't wrap my head around that. How doe those things go together?

[J N Winkler]

If anyone knows, how are broken-back curves problematic? Is there a certain distance where a broken-back curve becomes just two curves? And how is radius related to curvature? I can't wrap my head around that. How do those things go together?

Broken-back curves are considered aesthetically displeasing when the two curves can be seen at the same time from the driver's point of view (or one close to it).  There isn't a set distance at which two curves of the same sense are seen as separate curves rather than as a broken-back curve--it all depends on whether they are both visible at the same time.  The usual fix is to replace the two curves with a single sweeping curve of high radius that achieves the same bearing change, but site constraints can make this difficult to do.

Degree of curvature for roadway geometric design is based on the arc definition.  If you stand at a point on the curve, then the bearing change (in °) along the next 100 ft along the curve is equal to the curvature.  It is also equal to 5730 divided by the curve radius in feet.

There is a literature on aesthetics in alignment design that goes back to attempts in the late 1930's to combat highway hypnosis on the Autobahn (early designs featured long tangents with fairly short curves).  It has been found that designs that emphasize short tangents and long, high-radius curves ("flowing line") tend to correlate more closely with favorable accident experience than ones that feature long tangents with short, low-radius curves.  The flowing line is usually also regarded as more aesthetically pleasing.

More recently, the research program that yielded the Interactive Highway Safety Design Model (basically, a method for building a highway design concept element by element in such a way that the eventual accident rate can be estimated for design evaluation purposes) had a segment that focused on design consistency.  A design is said to be consistent (and, empirically, is associated with lower accident rates) if it communicates its alignment to the driver in such a way that he or she is not surprised by an unexpected feature.  Flowing-line alignments tend to score better in terms of design consistency than successions of long tangents and short curves, especially when the curves are of low radius.

I don't know if the IHSDM was used to check it, but the alignment shown in the schematics Rte66man linked to is much closer to a flowing line than the one that currently exists.  It's actually quite sweet, and with eight lanes should be free from capacity constraints for many decades, but at 20 miles in length I suspect it will take close to a billion dollars to build it.

[Scott5114]

I probably wouldn't be surprised if 10,000 vehicles were visiting WinStar on a daily basis. It is the largest casino in the United States in terms of gaming square footage: a whopping 600,000 sq ft. That's double the size of the 2nd and 3rd largest casinos. It's amazing none of the casinos in Las Vegas even rank in the top 10.

Amazing considering there's not even 600,000 of *anything* in Thackerville, as small as it is.

To give you an idea of how big WinStar is... casinos subdivide their floors into roughly equally-sized sections that each get a letter designation. (This letter is the first character of the machine location numbers, which is how the staff keeps from getting lost.) The first casino I worked at topped out at H. The one I work at now goes up to J. Both of these casinos are among the largest in the OKC metro area.

WinStar runs through the whole alphabet.

[In_Correct]

Why only Ardmore? I'd say go for broke and make the whole DFW-OKC corridor 8 lanes, to better facilitate travel between the two metro areas.

I begin to wonder if one day, we might see even a need for a new DFW-OKC corridor who could act as a relief route for I-35?

Perhaps the existing parallel routes can be upgraded.

I-35 runs on a pretty tight squeeze through Gainesville. I-35 has a pretty serious curve on the South side of town too. It's not as bad as the one at the edge of the Red River. But a 3rd lane added on the South bound side would get pretty tight in the right lane. I guess it's possible to add a third lane in each direction through Gainesville, but the slip ramps to the frontage roads would have to be completely re-done in order to be an acceptable length.

If they want to put I-35 on a new alignment to the West of Gainesville and Valley View they had better get on it ASAP before the available ROW gets gobbled up.

Regarding the DW's stores, I'm surprised any are still in business. I'm always amazed to see the one still open along US-287 outside Bellevue. It's such a desolate location and I rarely see more than one or two vehicles parked in front as I pass going to/from the Dallas-Fort Worth area. Most regular video rental stores are out of business. And there's plenty of free porn for anyone to stream on the Internet. I can't help but wonder if those DW's stores are fronts for various illegal operations.

The Google Earth imagery in much of the Dallas-Fort Worth area and up near the Red River on I-35 is recently updated. Apparently the Chickasaw Tribe is building a bunch of new stuff right off Exit 1 in Oklahoma. I can't tell if the huge new building south of the travel plaza is a big grocery store or just another big casino building. I mean, isn't the casino just up the road big enough?

I don't like the curve south of Gainesville or south of The Red River. Perhaps those would be better as Interchanges. The new alignment west of Gainesville and Valley View needs to include development as the current Interstate 35 is.

In Oklahoma Interstate 35 has many Wind Farms, and then in Thackerville there is WinStar which has many Sky Scraper and many other buildings. Continue in Gainesville there is many new buildings, several storeys tall, with in the view of The Interstate 35. Even in Valley View they have the ominous towering Martindale Feed Mill (even lights at night as if it was a sky scraper) which would probably like a new alignment instead of being crammed between an Interstate and a Rail Road. Also, the frontage roads were supposed to be realigned which gives more room to build a bridge over the rail road, no longer cutting Valley View in half and haveing to go through Denton to get on Interstate 35 or wait for train to finish.

Also with the Frontage Roads, they are supposed to keep the existing Red River bridges, space them out to convert them into frontage road bridges. This is necessary as emergency routes as well as traffic service to the Casinos.

I-35 runs on a pretty tight squeeze through Gainesville. I-35 has a pretty serious curve on the South side of town too.

That's one area that I wasn't happy they bumped up to a 75mph speed limit.  Anything over 70 there feels like a video game in real life.

The moment I travel 75 M.P.H. I find a slow box van

...

or these two curves which are dangerous. There are no warning lights and they have a regular speed limit.

[davmillar]

AADT certainly does drop quite a bit north of the casino:  by roughly 25%, in fact.
48,153 @ TX/OK state line

I actually used OklaDOT's vehicle count for the state line.  TxDOT had a value of 46,809 on the south side of the bridge for the same year (2017).

So that's about 1,300 vehicles that left OK but didn't make it to TX?  I blame the curve.

[kphoger]

So that's an average of about 1,300 vehicles per day that left OK but didn't make it to TX?  I blame the curve.

Edited for clarity.