Location Bandera Rd. (SH 16) from Loop 1604 to Diamond K Trail
Status Advanced design. See timeline below.
Description This project will convert Bandera Rd. to a
superstreet from just outside Loop 1604 to just south of FM
by converting the intersections at Hausman/Leslie and Cedar Trail to
restricted-crossing intersections, adding signalized turnarounds at
multiple intermediate locations, and
closing the crossover at Diamond K Trail. This project will also
construct a new signalized left turn from northbound Bandera Rd. to
Legend Trail and will expand the southbound Bandera left turn to
Hausman to two lanes.
restricted-crossing intersections will prevent traffic
on Leslie/Hausman and Cedar Trail from going straight or
turning left. Instead, all traffic will make a right turn, then use
a signalized turnaround about 1000 feet downstream to
make a U-turn and continue in the intended direction of travel. Left
turns from Bandera Rd. to those cross streets will still be allowed. To
better visualize this, click on
the "turning movements diagram" below.
project will also build an underground storm drainage system and will
include sidewalks throughout.
intersection at FM 1560 South was converted to a superstreet
configuration in 2018, and the intersection at Loop 1604 was converted
to a displaced left turn (DLT) in 2019, so this will close the gap
between these two improved intersections and complete the master plan
for this section of Bandera Rd. TxDOT plans to eventually continue the
superstreet configuration all the way to Triana Pkwy.
superstreet is also known by the more technical nomenclature of
"restricted crosssing U-turn" (RCUT) intersection.
LEFT TURN MOVEMENTS DIAGRAM
Click above to see a
simplified diagram of how drivers will make a left turn at each
this project will help The
Hausman/Leslie intersection experiences
significant to severe recurring congestion during both the morning and
evening rush hours. By eliminating the through-traffic and left-turns
on Leslie/Hausman and Cedar Trail, the green time required for those
movements can instead be combined with the left turn green time for
traffic turning from Bandera onto those streets. That essentially
eliminates the green time needed to service the cross streets, meaning
more green time can be allocated to the remaining movements,
which therefore moves more traffic through the intersection in the same
period of time. This configuration is expected to provide good
long-term congestion mitigation
based on 20-year traffic projections.
further explanation on how a superstreet functions and how it improves
traffic flow, see the main superstreets
it's currently not as congested, converting the Cedar Trail
intersection is necessary to provide continuity of improvement. If the
Cedar Trail intersection were not also converted, then it would soon
become a bottleneck due to the improved throughput on either side of it.
new left turn at Legend Trail will provide better access to the Stanton
Run neighborhood from northbound Bandera Rd. That traffic today must
make a U-turn at Cedar Trail and a U-turn at that location will not be
possible after the
conversion. Since a turnaround for southbound Bandera Rd. was necessary
at that location anyway, the left turn to Legend
Trail was a sensible addition.
the crossover at Diamond K Trail is necessary as it has become a
dangerous crossover location and will be more so in the future, and
direct crossovers like this within a superstreet
segment negate the improvements afforded by the superstreet.
Circle A Trail intersection:
With the previous project to realign the FM 1560 South intersection,
the intersection at Circle A Trail was changed to a
right-in/right-out configuration (i.e. no left turns or crossovers.)
This was done to streamline traffic operations in the area as that
intersection is fairly close to the new FM 1560 intersection. This has
understandably caused some consternation and grousing among residents
of Helotes Park Estates who are now required to make a right turn and
proceed to a turnaround 1/4th of a mile away in order to go south on
Bandera, adding about 1/2 mile to their trip.
(Some conspiracy-minded residents have even absurdly asserted that
this configuration is retaliatory in some way.)
part of the planning for the upcoming project, TxDOT asked their
consultants to re-evaluate the Circle A Trail intersection to determine
if it would be feasible to allow left turns from Circle A to southbound
Bandera. While certainly technically possible, the analysis showed that doing so
would be problematic from an overall operational standpoint. With a
superstreet, the signals on each direction of the corridor operate
independently and therefore can be better timed for the respective
traffic volumes, thus resulting in better overall traffic flow and
fewer delays for both directions of travel. Converting the Circle A
intersection to allow left turns would require the signals for
northbound and southbound Bandera at that location to be
interdependent, thus causing negative impacts to coordination of the
signals in one or both directions, especially during peak periods when
traffic volumes are unbalanced. Those negative impacts would initially
partially cancel-out the benefits of the superstreet, and those impacts
would increase over time as traffic in the corridor increases. There
were also safety issues with reintroducing left turn conflicts at one
location in a corridor that otherwise will not have any. The
negative impacts to the overall corridor operation were significant enough to
outweigh the benefits for a relatively small volume of traffic.
worth noting that reducing congestion along Bandera benefits the
residents of Helotes Park Estates and should reduce their overall
travel time in the corridor even if they are somewhat inconvenienced,
and that there are many locations where drivers are required to go a
little out of their way for the benefit of overall efficiency and
Timeline Construction is expected to begin in early 2022 and
take about two years to complete. The construction of an underground
drainage system added to the duration of this project.
This looks confusing.
It will cause lots of crashes. This is
of the first knee-jerk assertions made when an unconventional
intersection is introduced. With any change-- even more conventional
as new signals or lanes-- it naturally takes
drivers a little time to adapt. With a superstreet, because all traffic
on the intersecting
is forced to turn right, most confusion is quickly overcome
instinctively once the driver has turned or as the driver follows
other more experienced drivers through the intersection. Additionally,
because all traffic is flowing in the same direction and
is protected by signals, the likelihood of collisions is substantially
reduced, even during the adjustment period. Superstreets also
improve safety by reducing conflict points (the
point where vehicle paths cross) by half.
superstreets show improved safety. A study for
North Carolina DOT showed that superstreets reduced traffic collisions
by 46% and decreased crashes with injuries by 63%. A study of
superstreet intersections in Missouri showed a 54% reduction in
injury and fatal crashes. Many people predicted mayhem at the
Bandera/1604 displaced left-turn intersection, but crashes decreased
44% during the first nine months after it was completed.
How does this crazy design
traffic? How does adding even more traffic signals help?
This intersection design improves traffic because, by forcing all
traffic on the cross street to turn right, the green time for that can
be overlapped with the green time for traffic turning left from Bandera
onto the cross street. This essentially eliminates the green
that would be needed for the through
left turn movements on the cross street, so that time can then
the remaining movements, thus moving more traffic through the
intersection in the same
amount of time. Although there are extra signals, they are all much
more efficient and are better coordinated. See the "How a superstreet works"
section of the main superstreets page
for a deeper explanation of the superstreet "secret sauce".
All they have to do is adjust the
signal timing and that will solve the problem.
a common belief that congestion can be solved by simply
adjusting the signal timing. In some specific cases, that can be true,
but at a very busy intersection like this where there has to be
sufficient green time for eight different movements on every cycle, the
signals can only be optimized so much before the laws of physics win.
For example, the green time on Hausman could be extended to
out the peak period backups that occur there, but that means the light
will stay red longer for Bandera, which then increases the congestion
there. If the green time on Bandera is then increased to ease those
that means the light will stay red longer for Hausman and you're right
back where you started. So as you can see, it's really not as easy as
This causes people to have to go
out of their way, which is inconvenient and will require more time to
get across Bandera Rd.
folks understandably are peeved that to
or go straight on the cross street requires going out of one's way to
accomplish, and think that doing so will increase travel time. While
the former is true and will always be perceived as an
inconvenience by many drivers, wait times in general should be
overall congestion in
area reduced. As a result, travel time through the intersection should
shorter or no longer than it would be at a conventional intersection
even with the added time necessary to use the turnaround. Also
in mind that there are many other examples where traffic
wanting to make a left turn is prohibited from doing so due to a
median, freeway, or one-way street and must therefore turn right
first, then make a downstream U-turn or series of left turns,
so this situation is not unprecedented or unique to superstreets. In
fact, this has already been the case along much of this section of
Bandera Rd. due to the existing median.
This will increase emergency
response times in the area.
worked with the City of Helotes to mitigate concerns with response
times. As a
result, some adjustments to the plans were made including an emergency
vehicle median crossover at Hausman/Leslie, and additional pavement at
the northwest corner of that intersection to facilitate a turnaround
emergency vehicles. Again, it's worth noting that long stretches of
Bandera today do not have crossovers, and after the aforementioned
adjustments, the only crossover being lost for emergency vehicles is at
Diamond K Trail, which is being mitigated by ensuring that emergency
vehicles will be able to make a U-turn at Hausman/Leslie.
I'm headed south on FM 1560 (Hausman Rd.) and want to go to Wal-Mart,
Starbucks, Bill Miller's, or O'Connor High School, or head
southbound on Bandera Rd., how do I get
At Bandera Rd., you'll turn right, travel about 1000
feet to a turnaround (just past Little Caesar's Pizza), then head
southbound on Bandera where you can turn right at Bill Miller's,
Leslie Rd. (for O'Connor HS), Starbucks, or Wal-Mart,
or continue straight on southbound
Bandera. To return to Hausman Rd. from Bill Miller's, O'Connor,
Wal-Mart, you'll turn right onto Bandera Rd. and use a turnaround just
past Wal-Mart to return to Hausman Rd.
Why not build overpasses instead?
Across the country, traffic engineers have
discovered that innovative
intersections like this can produce good congestion relief and safety
at a fraction of the cost and construction time of flyovers and other
grade-separated solutions. This allows the limited
be saved and used for other needed projects.
and future traffic volumes and safety considerations along Bandera Rd.
aren't sufficient to justify the construction of overpasses or
conversion to a freeway, but they are in the "sweet spot" to support a
superstreet. Furthermore, the right-of-way along Bandera Rd. is not
wide enough for overpasses or a freeway, so the cost would be
considerably higher as additional right-of-way would have to be
obtained, which likely would result in the displacement of many
Why are there signals to leave
This is to
prevent slower moving vehicles from entering the faster traffic stream
and causing conflicts that could result in collisions or
Will the Circle A Trail
intersection be changed to allow left turns again?
No, that intersection is outside the scope of this project. TxDOT did
re-evaluate this intersection when planning this project; see the
discussion of this in the "How this project will help" section above.
Are there any other
superstreets in San
there have been two superstreet segments in San Antonio. One was on US
281 north of Loop 1604 and the other was nearby on Loop 1604 between
Braun Rd. and Culebra Rd. Both were built as short-term solutions while
funding for freeway expansions was obtained. The Loop 1604 superstreet
was replaced by a freeway in 2016, and the US 281 superstreet has now
also been replaced by a freeway. Unlike the 281 and 1604
superstreets, which were built as short-term fixes, the superstreet in
Helotes is considered a long-term
solution. A superstreet was also
considered for Bandera Rd. inside Loop 1604, but has been tabled while
a new corridor study
I heard that the US 281
superstreet was removed was because it was not working well, so why
build one here?
have been plans to upgrade US 281 to a freeway since 2000. However,
lawsuits by anti-toll activists and environmentalists and a resulting
requirement to conduct a lengthly environmental study delayed the
project for nearly two decades. In 2009, with congestion reaching
severe levels, a superstreet was proposed as a short-term "band-aid" to
help provide some relief, which it did
construction on the freeway was finally able to get started in 2017.
The traffic volumes on
US 281 exceed what a superstreet can optimally handle, so a superstreet
would never have been planned as a permanent solution there. However,
and projected traffic volumes on Bandera Rd. are in the "sweet spot"
for a superstreet to have a significant long-term positive impact. For
comparison, traffic volumes on the section of US 281 with the
superstreet ranged from 55,000 at Marshall Rd. to 100,000 at Redland
Rd., while on Bandera they range from 26,000 just west of FM 1560 South
to 43,000 at Loop 1604.
Who came up with this cockamamie
design? This won't work and is just a waste of money.
superstreet design has been used in several US states for the past
couple of decades and has a proven
track record of improving traffic wherever it has been implemented.
Both the US 281 and Loop 1604 superstreets showed appreciable
improvments, and computer modeling shows that this superstreet will do
the same. A superstreet
is one of several types of "innovative" or "alternative" intersection
being implemented across the country at intersections
where improvements from conventional expansions will be short-lived but
where conditions do
not warrant more expensive traditional upgrades such as
flyovers. Many people expressed similar doubts about the nearby
Bandera/1604 DLT intersection, but the new design has substantially
reduced congestion and crashes there.
the image below to open the detailed schematic for this
project from TxDOT with my own annotations added to help clarify and
explain the various elements. The schematic will
open in a new window that you can scroll and zoom.
DETAILED PROJECT SCHEMATIC
Click above to see the detailed
annotated schematic for
more details on this project, see this informational video from TxDOT.
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