Why are Texas interchanges so tall?
practical.engineering
Why are Texas interchanges so tall?
1–10 of 352 posts
Re: Why are Texas interchanges so tall?
#2I only had a quick skim so far, but I did not feel like the article gave a firm enough rationale?
I have seen scenarios in Texas when there is seemingly no other infrastructure or geography that could explain the over building.
Re: Why are Texas interchanges so tall?
#3So...
> Q: Why are Texas interchanges so tall?
>
> Frontage roads need grade separation, adding a layer.
> Texas has lots of frontage roads.
Or do they, in Texas? Or is it just that Texas has one famous one and people extrapolate that to mean the whole state is absolutely smothered in interchanges, until it looks like a scene from The Fifth Element?
Re: Why are Texas interchanges so tall?
#4> 37 bridges and more than 700 columns are crammed into this one spot to keep the roughly half a million vehicles flowing in every direction each day
Truly pitiful numbers for a project of this scale lol.
Re: Why are Texas interchanges so tall?
#5As cool as the engineering is, I avoid such interchanges at all costs since the being so high up gives me panic attacks when driving...
Re: Why are Texas interchanges so tall?
#6I only had a quick skim so far, but I did not feel like the article gave a firm enough rationale? I have seen scenarios in Texas when there is seemingly no other infrastructure or geography that could explain the over building.
The tl;dr to the article is "Texas freeways have frontage roads, which add at least one additional level to a traditional stack interchange, and that makes them taller than interchanges in e.g. California.
The broader question I've always had, that's not addressed in the article, is "so why do California and Texas build so many stack interchanges while the rest of the country mostly does not?"
Re: Why are Texas interchanges so tall?
#7So... > Q: Why are Texas interchanges so tall? > > Frontage roads need grade separation, adding a layer. > Texas has lots of frontage roads. OK, I buy that Texas has more grade-separated interchanges on average... but I'm not seeing how that turns into "Texas has more higher interchanges" which is what it feels like that question is asking. Frontage roads don't generally exist where 3+ highways intersect, so that sho…
There are frontage roads at most freeway interchanges in Texas.
Typical stack interchange elsewhere has 4 levels: freeway 1, freeway 2, freeway 1 left turns, freeway 2 left turns. Frontage roads add 5th and occasionally 6th levels.
The other thing not mentioned is the proliferation of separate express lanes, which often have dedicated flyover ramps as well.
Re: Why are Texas interchanges so tall?
#8So... > Q: Why are Texas interchanges so tall? > > Frontage roads need grade separation, adding a layer. > Texas has lots of frontage roads. OK, I buy that Texas has more grade-separated interchanges on average... but I'm not seeing how that turns into "Texas has more higher interchanges" which is what it feels like that question is asking. Frontage roads don't generally exist where 3+ highways intersect, so that sho…
Frontage roads don't generally exist where 3+ highways intersect… Or do they, in Texas?
I've lived in several states where frontage roads are common (under various names), and Texas was the place where they were most plentiful.
Older interchanges tended to run the frontage roads below grade to make them cheaper. But more recent ones tend to keep everything above grade due to flooding.
Or is it just that Texas has one famous one and people extrapolate that to mean the whole state is absolutely smothered in interchanges
Texas has a crazy number of highway interchanges. This is a partial selection of highway interchanges with frontage roads just in Houston. There are probably a hundred more across the state:
https://maps.apple.com/?ll=29.874104,-95.556634
https://maps.apple.com/?ll=29.726083,-95.459588
https://maps.apple.com/?ll=29.784165,-95.561947
https://maps.apple.com/?ll=29.785693,-95.777690
https://maps.apple.com/?ll=29.771646,-95.154931
https://maps.apple.com/?ll=29.940698,-95.293735
https://maps.apple.com/?ll=30.128100,-95.229756
Re: Why are Texas interchanges so tall?
#9I only had a quick skim so far, but I did not feel like the article gave a firm enough rationale? I have seen scenarios in Texas when there is seemingly no other infrastructure or geography that could explain the over building.
The tl;dr to the article is "Texas freeways have frontage roads, which add at least one additional level to a traditional stack interchange, and that makes them taller than interchanges in e.g. California. The broader question I've always had, that's not addressed in the article, is "so why do California and Texas build so many stack interchanges while the rest of the country mostly does not?"
That's an interesting thought. Are there statistics out there for "percentage of interchanges that are stacks"?
I've lived in CA and the Northeast. I didn't get the impression that either region uses them preferentially. Certainly I see them more in CA, but I feel like that is probably because the number of interchanges is higher, ha!
Re: Why are Texas interchanges so tall?
#10As cool as the engineering is, I avoid such interchanges at all costs since the being so high up gives me panic attacks when driving...
Me too! I can’t avoid them all the time but I slow down as much as I can safely (this is Texas so everyone drives at least 20 miles over the limit) and look straight ahead.