| San Antonio Area Roads & Freeways
|This page last updated February 19, 2020
are some of the most common questions or complaints I get about San
Antonio roads and freeways.
following projects have FAQ sections on their own pages:
- Why don't they plan and build new roads before new developments are built?
is a lot easier said than done. Transportation agencies don't
know what's coming until a developer submits their plans, and even
then, there's no guarantee the development will be built. When a
development is submitted, the developer is usually required to conduct
a traffic impact analysis and then mitigate the projected impacts,
either by constructing improvements or paying an impact fee. Generally,
the impacts from individual developments will be in the
immediate area, and mitigating improvements will usually consist of
turn lanes, intersection improvements, and signals. The issue is that
there is really no way of forecasting what the impacts
will be to roads further afield. For example, how many people from a
new development will head north on the nearest freeway vs. those that
will head south? There's no way to know until that traffic
materializes. Furthermore, the impact from a single development further
afield is generally trivial, so even if it could be accurately
determined, it would not be enough to require mitigation. Instead, it's
the cumulative impact from multiple developments over time that cause
those issues, and so it's impossible to retroactively assess specific
impacts to individual developments.
if they had a crystal ball, it still takes several
years before road projects can come to fruition. First, there's the
design and engineering, then environmental clearances, obtaining
funding, then right-of-way acquisition and utility relocation. All of
has to happen before the actual project to build or widen a road can
start, so it's generally a minimum of five years before a major road
project can break ground. In the meantime, they can't legally stop
the developer from
continuing with their project, so those new developments are often well
underway or even complete before road projects can get
underway. See also the last question on the road construction FAQ page.
- So why not, then, build or widen roads ahead of the development?
good idea, except that with all of the existing needs that struggle to
get funded, there's certainly not money just lying around to build new roads out in the
middle of nowhere based on hypotheticals. And if they did and the
growth didn't come for some reason, that would result in a lot of wasted money.
For example, the Poteet-Jourdanton Freeway on the South Side was overbuilt
when it was initially constructed back in the '50s because it was
believed that San Antonio would grow south. It didn't, and,as a result,
it's much more road (which costs more to mainain) than is needed for the level of traffic it carries
even today. See also the last question on the road construction FAQ page.
was the first freeway built in San
The section of the lower level
of I-10 (then just US 87) between Woodlawn and Culebra. It quietly
opened in July
1949. (See the San
Antonio Freeways History page for a complete
history of the freeway system.)
the deal with SH 211? It's a road
to nowhere and a waste of money.
The first section of SH
211 opened in 1990 to provide access to
the now-defunct Texas Research Park. Because of its location, TxDOT
planners knew that it would make an ideal location for a far west Bexar
County beltline, an idea that had been around for decades. Like many
projects, construction on SH 211 was split into several
segments due to funding constraints. Unfortunately, due to issues with
right-of-way acquisition, the missing middle segment has languished
for years. However, in 2009, Bexar County agreed to
build the missing segment and get reimbursed by the state over several
years. See the SH 211 page
doesn't TxDOT upgrade Bandera Rd.
through Leon Valley?
the late '80s, various
upgrades to Bandera Rd. in that area have been proposed, including adding flyovers at major
intersections and an elevated tollway, but the City of Leon Valley
vetoed all of the plans on
the belief that such upgrades would hurt local businesses by speeding
traffic through the city (a serious
fallacy in my opinion; congestion hurts businesses more than
improved access would.) Fortunately, fresh leadership in
recent years has resulted in a change to Leon Valley's official
position and will hopefully result in much-needed improvements. See the Bandera Road proposals page for more details on current planning for that corridor.
aren't traffic signals in San Antonio
most of them are. See the City
of San Antonio's traffic signal management page
for details and see this video to see it in action. That said, if you're on a road and it doesn't seem like
the signals are synchronized, here are some possible reasons why:
- You're traveling faster than the speed limit.
Signals are synchronized for to allow a group of cars (a "platoon")
moving at the speed limit of the roadway. If you're speeding and get
out ahead of the platoon, you could arrive at the next signal when it's still
- You're traveling significantly slower than the
speed limit (either because you're lollygagging or due to
traffic.) If you fall behind the platoon, you could arrive at the next
signal as it turns yellow or red.
- The road you're on intersects with another road
where signals are synchronized. If the synchronization on one roadway
conflicts with that on the other, then one will have to prevail over the
headed in the opposite direction of the timing. Sometimes, signals on a
roadway are only timed for traffic headed in one direction (i.e. the
direction with the heaviest flow of traffic.)
traffic volumes on the road you're on exceed the capacity of the
traffic signals. For a more in-depth explanation, see the related
question in the FAQ on the Bandera Road page.
- Congestion in San Antonio could be solved by just timing the signals better.
This is a common assertion and can be true in some specific
cases. But most of the time, it's way more compllicated. At most busy
intersections, there has to be
sufficient green time for eight different movements on every cycle, so
signals can only be optimized so much before the laws of physics win.
For example, the green time on road A could be extended to
out the backups that occur there, but that means the light
will stay red longer for road B, which then increases the congestion
there. If the green time for road B is then increased to ease those
that means the light will now stay red longer for road A and you're
back where you started. So as you can see, it's really not as easy as
it sounds. Then scale that zero-sum complexity over an entire corridor
and you see just how naive "just time the lights better" really is.
- If I'm at a red light and nobody is coming
on the intersecting road, why doesn't the light turn green for me right
are several reasons why this can happen:
- If the intersecting road has synchronized traffic
signals, then your signal will have to wait for scheduled gaps in that
"green wave" before it can change. When signals are synchronized, the
green times on the major road are fixed by design and typically can't be preempted except for
- The minimum
green time on the intersecting roadway
hasn't yet expired. Whenever a signal turns green, there is a set
minimum amount of time it will stay green. If a pedestrian signal has
been activated, the minimum green time will usually be longer.