Sunday, November 26, 2023

Recent TxDOT study recommendations reflect new reality and introduce complications

This week we have another excellent analytical guest post from Houston Freeways author Oscar Slotboom!
In September TxDOT held public meetings for its preferred alternative for future improvements to Interstate 45 North Freeway from Beltway 8 to Loop 336 (south) in Conroe, and in October meetings were held for SH 225 and the East Loop.
Both studies recommended the addition of 4 elevated lanes (2 each way) to these freeways, with minimal or negligible right-of-way acquisition.
This can be interpreted as a new reality that it is no longer politically feasible to acquire right-of-way for freeway improvements in the Houston area. Of course, right-of-way acquisition for NHHIP was the main reason for the controversy which resulted in a two-year pause on the project, and then a revised schedule which delays completion to 2042.
Opposition to right-of-way acquisition is a tactic used by anti-highway activists to block freeway improvements. Of course TxDOT can go up with elevated lanes, which is the recommendation for the corridors of these studies. But this introduces complications.
Complications with Elevated Lanes
The first complication is cost. Elevated lanes are very expensive. There are two elevated lanes projects in progress on I-35 in San Antonio. The I-35 NEX Central project, awarded in March 2021, adds six elevated lanes to a 9.5 mile section in northeast San Antonio. The low bid was $1.515 million, or $159 million per mile. Highway construction costs have increased around 56% since March 2021, and the estimated inflation-adjusted cost is around $248 million per mile. The NEX South project, awarded in May 2023, adds six elevated lanes to a 4 mile section for $700 million, or $175 million per mile with an inflation-adjusted value of $186 million per mile. For comparison, complete reconstruction and expansion of the Gulf Freeway between NASA 1 and Galveston currently in progress costs around $60 million per mile, although it would cost more (up to $90 million per mile) when adjusted for recent inflation.
Using the $186 million value from this year and adjusting for fewer lanes in the Houston recommendation, we can expect elevated lanes to cost at least $125 million per mile and probably around $150 million per mile. When costs are high, it takes longer to get funding, and it's possible that full funding may never become available if construction costs become too high.
The second complication is access to elevated lanes. Access points to elevated lanes are more widely spaced than managed lanes at ground level. For example, the I-45 study recommends access at Beltway 8 and FM 2920, a distance of 10 miles without any entrances or exits (except for a connector to the Kuykendahl Park & Ride near Beltway 8, which would mainly serve transit vehicles). Long elevated structures also make emergency services access more difficult and complicated. In the case of SH 225, many trucks are making pickups and deliveries in the area, so many would not be able to use elevated lanes.
I-45 Study Recommendation
Elevated lanes are shown in the center of the freeway on a single structure. Generally speaking, the existing freeway configuration and footprint would remain unchanged. The elevated structure would replace the existing reversible HOV lane between Beltway 8 and FM 1960, resulting in a net gain of 3 lanes, and appears to replace the two existing "diamond" lanes north of FM 1960, resulting in a net gain of only two lanes (at a very high cost). As I mention in my detailed comments below, I think there is an opportunity to add a new general purpose lane in one direction, since the columns for the elevated structure don't require the full width of the HOV lane and the diamond lanes.
In addition to four elevated lanes, the study recommends other less expensive improvements to frontage roads and intersections. However there is no specific mention of completing the interchange at SH 99 (Grand Parkway), which is probably the most pressing need in the corridor. Realistically, I don't think we'll see any work on the elevated lanes until the adjacent section of NHNIP south of Beltway 8 is fully completed. The sections between Beltway 8 and Loop 610 are scheduled to be completed between 2034 and 2042.
CLICK HERE to view my detailed public comments for I-45
SH 225 and Loop 610 East Recommendation
While the I-45 north corridor is mostly the same in terms of existing design along its full length, the SH 225 and Loop 610 study area has a wide variety of situations, including the ship channel bridge. My main complaint is applying a "one size fits all" recommendation for expensive elevated lanes, when a variety of design approaches could solve problems better and more quickly at a much lower cost. The study presentation shows two elevated structures, one in each direction with two lanes between the main lanes and frontage roads. See my public comments for specific concerns, and my suggestions for less-expensive and more-effective improvements.
CLICK HERE to view my detailed public comments for the SH 225 and East Loop
Why not a hybrid approach, with elevated lanes where needed and freeway-level lanes elsewhere?
Much of the SH 225 corridor has vacant land or low-value commercial property along one or both sides. Does it make sense to build expensive elevated lanes when the impact of expanding the freeway width is minimal? I don't think so. That's why I would prefer to see a hybrid alternative which uses elevated lanes only where ground-level widening has a large impact. The freeway corridor should be widened with new right-of-way where the impact is low or minimal. This reduces construction cost, and also provides access to the new lanes where the new lanes are built at freeway level.

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At 9:47 AM, November 26, 2023, Blogger George Rogers said...

Thats what they do with the LBJ expresslanes in Dallas. They have it at grade except where either right of way is too difficult or there would be too much reworking of interchages to get a cost advantage by staying at grade, in those cases they dig a trench, which makes sense in dfw.

At 6:51 AM, December 06, 2023, Blogger TheCastle said...

I'm actually okay with the concept of express lanes through areas. One of the things that makes Houston freeways slow is too many on/off ramps too close together. It would be nice for through traffic to not have to contend with all the slow downs from poorly designed interchanges and people who can't merge, like on the 288 tollway. I just spent 2 weeks in Germany, I was absolutely impressed with how good ground transportation is. I stayed in the city center of Frankfurt about the same population as Houston. Took a cab ride at 7:30am from the old city center, which included sections of unlimited autobahn to the frankfurt airport. All the lights were coordinated so we never hit a single red. My ride was less than 25 minutes with stretches doing 90+mph (legally, converted from Kph) in the rain during rush hour. From drop off at the front door until I was sitting at my gate was 10 minutes at an airport that sees 3.5x the passenger volume of IAH. That was a revelation to me how bad the roads and airport system is in Houston. I could not drive from downtown Houston to IAH at 7:30am in 25 minutes, nor can I get through al the new traffic lights and TSA strongmen in 10 minutes...... We could make some real improvements to streamline transportation here.... Especially keeping trucks out of the left lanes, like Germany does on the Autobahns... Also emigration in IAH is pathetic. It took me 20 minutes to get through that hurdle, Germany 2 minutes...


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