| 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:
don't they plan and build new roads before new developments are built?
This is answered in detail on the Why don't developers
have to expand the roads first? 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.
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
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
- 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
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
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
- Congestion in San Antonio could be solved
by just timing the signals better.
is a common assertion and can be true in some
cases. But most of the time, it's way more complicated. 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.