Location Bandera Rd. (SH 16) from Legend Trail to Diamond K Trail
Status Construction underway (39% complete)
Timeline Construction
began in August 2022 and is projected
to be complete in mid 2024. Recent news reports indicate the City of
Helotes and TxDOT have agreed to accelerate the project completion by
six months, but I have not yet confirmed this.
Summary
Here is a brief summary of this project:
This
project will convert intersections along Bandera Rd. to "Restricted
Crossing U-Turn" (RCUT) intersections from Legend Trail
to Diamond K Trail.
This
will modify the intersections at Hausman/Leslie and Cedar Trail to
force traffic on those cross streets to turn right, i.e. left turns and
straight-through movements from those cross streets will be blocked,
but left turns from Bandera Rd. to those cross streets will still be
allowed.
Downstream
turnarounds will then allow traffic from the cross street to
make a U-turn to return to their intended direction of travel. (See diagrams below.)
This
is the same configuration as at Bandera Rd. and FM 1560 South.
Doing
this reduces the
number of
traffic
signal
phases required to move traffic through the intersections thereby
allowing for longer green times for all movements without extending the
overall cycle time. This allows for more traffic to move through in the
same amount of time, thus reducing
wait times and congestion. (See
explanation below.)
While
it seems confusing at first, it's actually pretty easy to navigate.
Studies
of past RCUTs show improved safety as well as reduced congestion.
A
new left turn will be built from northbound Bandera Rd. to Legend Trail.
The
crossover at Diamond K Trail will be closed.
Bandera
Rd. will be widened to three lanes each direction between
Hausman/Leslie and Circle A Trail.
Based
on community feedback, TxDOT directed their consultant to study
possible changes at Circle A Trail, but that study determined that the
changes desired by local residents would result in increased crashes
and congestion due to the disruption that would be introduced by the
signal timings required to facilitate left turns from Circle A Trail to
SB Bandera Rd.
(See further
explanation below.)
Description This project will convert the intersections
on Bandera Rd. at Hausman/Leslie and Cedar Trail
to Restricted Crossing U-Turn (RCUT) intersections, add signalized
turnarounds at
multiple intermediate locations, and
close the crossover at Diamond K Trail. This project will also
construct a new signalized left turn from northbound Bandera Rd. to
Legend Trail, will expand the southbound Bandera left turn to
Hausman to two lanes, and will widen Bandera to three lanes in each
direction between Hausman/Leslie and Circle A Trail.
The
RCUT 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 following diagram.
LEFT TURN MOVEMENTS DIAGRAM
Click above to see a
simplified diagram of how drivers will make a left turn at
each
intersection
This
project will also build an underground storm drainage system and
sidewalks throughout.
The
intersection at FM 1560 South was converted to an RCUT
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
RCUT configuration all the way to Triana Pkwy. as traffic
warrants.
An
RCUT intersection is also known as a "superstreet".
Typical RCUT
intersection
How
this project will help The
Hausman/Leslie intersection experiences
significant to severe recurring congestion during both the morning and
evening rush hours. By forcing traffic on Hausman/Leslie to turn right,
this will overlap that traffic with the corresponding left turn from
Bandera and will eliminate the need for green time
for the
left
turn and straight-through movements from those streets. The green time
that would have been needed for those movements can instead be
allocated to the remaining movements,
which therefore will allow more traffic through the intersection in the
same
period of time, thus significantly reducing wait times and congestion.
If
all of that sounds like technical gibberish, here's another way of
explaining it: At the conventional intersection, drivers who
arrive as
the light turns red have to wait for three or four other
directions to get a green light before their light turns green again.
At an RCUT intersection, drivers only have to wait for one signal change
before they get a green again. Drivers
then needing to use the turnaround may have to subsequently wait for
one more signal change, but that's still less than before.
Additionally,
with an RCUT, each half of the intersection operates independently
of the other, so the signals along each direction of Bandera Rd. can be
timed separately from the other direction, which means better
coordination and synchronization are possible.
Modeling
showed that
this configuration is expected to provide good
long-term congestion relief
based on 20-year traffic projections.
Example
Bandera-Hausman/Leslie
Signal Timings
The whole pie below represents
the time for a full signal cycle (~150 seconds.)
The pieces of the pie show the
proportion of green time each movement gets during each cycle.
Left/right arrows represent Bandera Rd.
With
an RCUT, all the movements except the through movements on Bandera get
combined, and in this example, are combined into the biggest piece of
the pie from the conventional intersection. After
doing so, that slice can (and probably will) be increased as needed to
accommodate Hausman/Leslie traffic, and even after doing so, everyone
still gets more green time than they had in the conventional
intersection.
Current
timing splits are
approximate as they change during the day, but are typical.
Timings
were obtained by yours truly by monitoring the intersection for three
half-hour periods during a Wednesday in April 2022.
Finally, in an
RCUT, the signals on each side of Bandera Rd. can be timed
independently of the other, and thus would be two separate pies, so
the RCUT chart below combines
both directions for simplicity.
Cedar Trail intersection
Although
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 as its conventional signal cycle would not
be congruous with the improved throughput at intersections upstream in
both directions.
Legend Trail intersection
The
new left turn at Legend Trail will provide new direct access to the
Stanton
Run neighborhood from northbound Bandera Rd. That traffic today must
make a U-turn at Cedar Trail which will be
prohibited after the
conversion. Since a turnaround for southbound Bandera Rd. will be
necessary
at that location anyway, the left turn to Legend
Trail was a sensible addition. The new signal it introduces
for
southbound Bandera will be integrated into the overall signal
coordination afforded by the upstream RCUTs.
Diamond K Trail intersection
Closing
the crossover at Diamond K Trail is necessary as it has become an
increasingly
dangerous intersection and will be more so in the future, and
direct crossovers like this within an RCUT
segment negate the safety and congestion improvements the RCUTs
provide.
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
signalized 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 and is
between it and the southbound to northbound turnaround. 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 ¼ of a mile away in order to go south on
Bandera, adding about ½ mile to their trip.
(Some conspiracy-minded residents even absurdly
assert
that
this configuration is retaliatory in some way.)
Based
on resident feedback as
part of the planning for the upcoming project, TxDOT asked their
engineering
consultant 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 still physically possible, the analysis showed that
doing so
would be problematic from an overall operational standpoint. With the
RCUT intersections, the signals in 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 all 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 return to
interdependent operation, thus complicating the coordination
of
the
signals in one or both directions of the remainder of the corridor
resulting in negative impacts would nullify
the benefits of the RCUTs and result in this intersection
becoming a new bottleneck, the significance of which
would increase over time as traffic in the corridor increases.
There
were also safety issues with reintroducing left turn cross traffic
conflicts at one
location in a corridor that otherwise will not have any. The
negative impacts to the overall corridor operation and safety were
significant enough to
outweigh the benefits for the relatively small volume of traffic from
Circle A Trail.
It's
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 with the additional travel time
required to execute the right-turn and U-turn,
and that there are many other locations where drivers are required to
go a
little out of their way for the benefit of overall efficiency and
safety, including some existing nearby legacy locations along
Bandera
Rd.
FAQ
This looks confusing.
It will cause lots of crashes. This is
always one
of the first visceral assertions made when an unconventional
intersection is introduced. With any change-- even more conventional
changes such
as new signals or lanes-- it naturally takes
drivers a little time to adapt. With an RCUT, because all traffic
on the intersecting
street
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. RCUTs also
inherently
improve safety by reducing conflict points (the
point where vehicle paths cross) by half.
Statistics for RCUTs show improved safety. A study for
the
North Carolina DOT showed that RCUTs reduced traffic collisions
by 46% and decreased crashes with injuries by 63%. A study of RCUT
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, despite higher
traffic volumes in 2021, the number of crashes was less than
half of the number in 2017.
How does this crazy design
improve
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
time
that would be needed for the through
and
left turn movements on the cross street, so that time can then
be
reallocated to
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 an RCUT works"
section of the main Retricted Crossing U-Turn
intersections page
for a deeper explanation of the RCUT "secret sauce".
All they have to do is adjust the
signal timing and that will solve the problem.
It's
a common belief that congestion can be solved by simply
adjusting the signal timing. In some specific cases, that can be true,
but at very busy intersections like Hausman and Bandera 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
help clear
out the peak period backups that occur there, but that means the light
will stay red longer for Bandera, which then increases the wait times
and backups
there. If the green time on Bandera is then increased to ease those
backups,
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
it sounds.
This causes people to have to go
out of their way, which is inconvenient and will require more time to
get across Bandera Rd.
Some
folks understandably are peeved that to
turn left
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
shorter
and
overall congestion in
the
area reduced. As a result, travel time through the intersection should
typically be about the same as it would be at a conventional
intersection
even with the added time necessary to use the turnaround. Also
keep
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 RCUTs. In
fact, this has already been the case along much of this section of
Bandera Rd. due to the existing median, for example, leaving any of the
businesses along Bandera between Hausman/Leslie and Cedar Trail.
This will increase emergency
response times in the area.
TxDOT
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
for
emergency vehicles. Again, it's worth noting that most of this stretch
of
Bandera today does not have intermediate 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.
If
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
there?
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,
Starbucks, or
Wal-Mart, you'll turn right onto Bandera Rd. and use a turnaround just
past Wal-Mart to return to Hausman Rd., which, in several of those
scenarios, is actually more convenient than what's there today.
This will benefit traffic on
Bandera more than that on Hausman and Leslie.
That's probably a fair assessment. But, traffic on Hausman and Leslie
will still benefit. Those making a right turn onto Bandera will see the
most benefit, but even those turning left onto Bandera or crossing
Bandera should still see some modest benefits due to overall reduction
of
congestion at the intersection and corresponding decreased travel
times. Those same people almost
certainly also use Bandera Rd. at some point in their daily lives, so
they'll realize those benefits as well.
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
traditional
grade-separated solutions. This allows the limited
transportation
dollars to
be saved and used for other needed projects.
The current
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
RCUTs. 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
businesses.
Why are there signals to leave
the turnarounds?
This is to
prevent slower moving vehicles from entering the faster traffic stream
and causing conflicts that could result in collisions or
congestion.
Will the Circle A Trail
intersection be changed to allow left turns again?
No, that intersection is outside the scope of this project, although
TxDOT did
re-evaluate this intersection when planning this project; see the
discussion of this in the "Circle A Trail intersection" section above.
Are there any other
RCUTs in San
Antonio?
Yes,
there have been two RCUT 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
approval and funding for freeway expansions was obtained. As intended,
the Loop 1604
RCUT
was replaced by a freeway in 2016, and the US 281 RCUT was replaced by
a freeway in 2021. Unlike the 281 and 1604 RCUTs, which were built as
short-term fixes, the RCUTs in
Helotes are considered a long-term
solution. RCUTs are now also proposed for Bandera
Rd. inside Loop 1604 and for Loop 1604 from US
90 to Macdona Lacoste Rd., and have been constructed on a
segment of Loop 337 in New Braunfels,
I heard that the US 281
"superstreet" was removed because it was not working well, so why
build one here?
That is false. There had always been plans to upgrade US 281 in that
area to a freeway going back to
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, the "superstreet" (RCUT intersections) was proposed as a
short-term "band-aid" to
help provide some relief, which it did
until
construction on the freeway was finally able to get started in 2017.
The expected future traffic volumes on
US 281 exceed what RCUTs can optimally handle, so that
would never have been planned as a permanent solution there. However,
the current
and projected traffic volumes on Bandera Rd. are in the "sweet spot"
for RCUTs to have a significant long-term positive impact. For
comparison, traffic volumes on the section of US 281 with the RCUTs
ranged from 55,000 at Marshall Rd. to 100,000 at Redland
Rd., while on Bandera they range from 23,000 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.
The RCUT design and variations have been used in
several US states
for more than 20
years and has a proven
track record of improving traffic wherever it has been implemented.
Both the US 281 and Loop 1604 RCUTs showed appreciable
improvements, and computer modeling shows that these RCUTs will do
the same. An RCUT
is one of several types of "innovative" or "alternative" intersection
designs
being implemented across the country at intersections
where benefits from conventional intersection improvements would be short-lived
but
where conditions do
not warrant more expensive traditional upgrades such as overpasses.
Many people expressed similar skepticism about the nearby
Bandera/1604 displaced left turn (DLT) intersection, but the new design
has substantially
reduced congestion and crashes
there.
Schematic Click
on
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
this project
Video TxDOT
has a good video that describes this project:
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