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Bandera Road - SH 16 Other San Antonio Area Roads
Bandera Road/Leon Valley study

This page last updated October 27, 2022

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The proposals on this page are still in development
The cities of San Antonio and Leon Valley and the Texas Department of Transportation are currently in the midst of a years-long study to determine how to improve Bandera Rd. As a result, the details discussed below are subject to change.

This page includes details about previous concepts that are no longer being considered in order to provide context and background to the ongoing studies.

Bandera Road (SH 16) between Loops 410 and 1604 in Leon Valley and Northwest San Antonio is one of the most congested road in the region. About 70,000 vehicles a day use the southern half of the route and about 40,000 use the northern half. To put that into perspective, the section of Loop 410 on the South Side between I-35 and I-37 carries about 50,000 vehicles per day, and the stretch of Loop 1604 between SH 151 and US 90 carries less than 40,000 vehicles per day. So improvements to Bandera Road are urgently needed and have been for decades, but the road has languished with only a few minor improvements since the mid '80s.

The problem hasn't been that officials haven't recognized this need; a freeway was actually planned for Bandera Rd. during the 1950s and 60s, and more recently, there have been at least seven studies and proposals to upgrade Bandera Rd. over the past three decades. The primary snag has been finding improvements that are amenable to the City of Leon Valley. A flyover proposal by TxDOT back around 1990 was shot down by Leon Valley leaders, and an alternative plan that proposed building an elevated highway along Leon Creek and bypassing Leon Valley altogether also was nixed for other reasons. This schism has resulted in the repeated stalling of efforts to make major improvements to Bandera Rd.

Then, in 2009, the Alamo Area Regional Mobility Authority (ARMA) included Bandera Rd. in their regional toll system plan. The conceptual proposal was an elevated tollway along the length of Bandera between the loops. However, subsequent feasibility studies-- and simmering opposition from several constituencies-- scuttled that plan. TxDOT subsequently took over studying other options to relieve congestion in the corridor.


Current planning

As discussed above, TxDOT has been studying a number of options to reduce congestion and improve safety on Bandera Rd. for many years. In 2018, the City of San Antonio joined those ongoing Bandera Rd. planning efforts and launched a "community planning process" to develop a overarching plan for transportation, land use, urban design, and economic development along Bandera Road. The first public meeting in this combined planning effort was held April 29th, 2019, with additional meetings held in December 2019, June 2021, and October 2022.

Traffic study
In order to determine the best options for improvements, TxDOT studied traffic patterns along the corridor and identified three major traffic movements that need to be addressed:
  • Through traffic: Current studies indicate that about 9-15% of traffic on Bandera travels from Loop 410 to Loop 1604. However, with continuing growth along Bandera outside Loop 1604, it is expected that percentage will increase.

  • Local traffic: This is traffic with origins and/or destinations in the Bandera Road corridor (i.e. local residents and/or patrons of local businesses.)

  • "Zig-zag" traffic: This consists of traffic using a portion of Bandera for cross connectivity between a thoroughfare on one side of Bandera to another thoroughfare on the other side of Bandera. Analysis of traffic data revealed that there are three of these major movements:
    • Eckhert - Mainland/Guilbeau
    • Loop 410 - Grissom
    • Loop 1604 - Prue


Major "zig-zag" traffic patterns on Bandera Rd.


These "zig-zag" movements create two unique problems:
  • They inject a large amount of traffic into the through route for a short distance. 
  • They generate massive left turn movements at multiple intersections. Left turns are the most inefficient traffic movement and require substantially more signal time, which then reduces the amount of signal time available for the other approaches.
The traffic study also looked at projected traffic volumes through the year 2047 which showed increases of around 40% south of Braun to over 85% north of there.

Options evaluated

With those traffic patterns in mind, several options were evaluated:
  • Conventional widening: This plan would add one lane in each direction to the existing lanes (i.e. eight lanes from the Loop 410 ramps to Guilbeau and six lanes from there to Loop 1604), make conventional intersection improvements, and improve access management (i.e. limiting driveways.)

  • RCUT: This would convert all intersections in the corridor to "Restricted Crossing U-Turn" (RCUT) intersections. Additional through lanes could also be included in this plan. This option is discussed in more detail below.

  • Boulevard: This concept would add a two-lane frontage road on each side of the existing mainlanes, which would be rebuilt. This option is discussed in more detail below.

  • Thoroughfare network improvements: TxDOT identified and modeled several possible thoroughfare connections that could remove much of the "zig-zag"  traffic from the section of Bandera. Of the options explored, a connector from Eckhert at Abe Lincoln to Bandera at Mainland and/or Guilbeau had the most promise. The City of San Antonio has agreed to study this further and would be responsible for building it should it be determined to be feasible. 

  • Reversible connector: This concept would build an elevated, reversible roadway to provide a direct express lane for one or more of the "zig-zag" traffic movements. It would be reversible, meaning it would change direction between the morning and afternoon rush hours to flow in the direction of peak traffic.

  • Traditional freeway: This would build a standard freeway corridor with mainlanes, overpasses, ramps, and access roads..

  • Elevated throughway: This proposal, commonly-referred to as the "flyover" plan, would consist of shifting the existing lanes slightly further outward and building an elevated roadway on piers located in the center median. This elevated roadway, running from Loop 410 to Loop 1604, would overhang the surface lanes and consist of a single lane and a shoulder in each direction to carry through traffic, similar to the flyovers connecting Bandera and Loop 410. Due to right-of-way constraints that limit possible "touch-down" locations for entrance and exit ramps, access points along the elevated section would be very limited. The elevated lanes would tie-into the existing flyovers connecting to Loop 410. Although this was included as a possibility in an early toll road plan, this option would not be tolled.
After the initial study, the options were winnowed down to four:
  • Conventional widening and intersection improvements: This would widen Bandera to four lanes each way, add turn lanes at intersections, and eliminate the "split phasing" of the traffic signals at many of the intersections that allows only one direction of the cross street to have a green signal at a time. This option provided the second lowest reduction in congestion reduction meeting only 62-66% of 2047 projected demand, mostly due to the remaining inherent inefficiencies of the intersections.

  • Boulevard: This option is discussed in more detail below. Of the four options studied, this provided the least reduction in congestion meeting only 57-64% of 2047 projected demand (again, mostly due to remaining inherent inefficiencies at the intersections), actually increased intersection conflicts because of the addition of frontage roads, and required the the most additional right-of-way. 

  • RCUT: This option is discussed in more detail below. It provided good congestion reduction meeting 84% of projected 2047 demand.

  • RCUT with grade separations: This would combine both the RCUT option along the entire corridor and the "flyover" plan from the Loop 410 connectors to Guilbeau. However, the flyover lanes would instead descend below ground level through Leon Valley. This option had the best reduction of congestion meeting 90-93% of projected 2047 demand. However, it was also by far the most expensive at $410 million, had the longest construction duration and impact, and had the most long-term maintenance costs, mostly due to the depressed segment needing stormwater pumping, air ventilation, and fire protection.
TxDOT branded all the options except the boulevard as "parkway" options, meaning that in addition to expansion, efforts would be made to beautify the corridor. (The boulevard proposal would also include beautification efforts, although they would be more limited than the other options.) All the options would also consolidate driveways and median crossovers.

After further study, the study participants settled on the RCUT plan as the preferred option as it met the needs of congestion relief, safety improvement, and ancillary aesthetic, pedestrian, and bicycle enhancements at a reasonable cost. 

With that decision, the next steps will be to finalize buy-in from the stakeholders, then move to advanced design and planning, environmental study and clearance, and final engineering. At the same time, efforts will be made to identify funding as there is currently no funding earmarked for this project. If all goes well, construction could begin around 2024 and be complete around 2027.

Projected 2047 travel time comparisons for the various options





* Morning (AM) peak period is from 6 a.m. to 9 a.m. Afternoon (PM) peak period is form 4 p.m. to 7 p.m.
** No-build travel time on Guilbeau Road to Eckhert Road (AM) trip is due to the SH 16 bottleneck north of Guilbeau Road, which limits the volume of traffic that can reach this segment of SH 16 in the AM peak period.



RCUT proposal

Of the four options studied, the RCUT concept was selected in 2022 as the preferred option to carry forward. This would convert the nearly all of the signalized intersections on Bandera Rd. to Restricted Crossing U-Turn (RCUT) intersections, add signalized turnarounds at multiple intermediate locations, close all of the unsignalized crossovers, and eliminate the signalized intersections at Reindeer Trail and Poss Rd. This plan would also widen Bandera to four lanes in each direction, consolidate many of the driveways along the corridor, add pedestrian and bicycle amenities, and add curbs and storm drains.

The RCUT intersections will prevent traffic on the intersecting roads from going straight or turning left. Instead, all traffic will make a right turn, then use a signalized turnaround typically 1000 or so 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.

An RCUT intersection is also known as a "superstreet".


Typical RCUT intersection


How this will help

Most of the intersections on Bandera experience moderate to severe recurring congestion during rush hours and in many cases at other times during the day and on weekends. This is due to the need for the signals to service five separate movements per cycle. With an RCUT, by forcing traffic on the cross streets to turn right, this will overlap that traffic with the corresponding left turn from Bandera and will eliminate the need for discrete green time for the left turn and straight-through movements from those streets, resulting in just two movements to be serviced per signal cycle. The green time that would have been needed for the other three 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 light have to wait for three or four other directions to get a green light before their light turns green again. At an RCUT, drivers only have to wait for one signal change before they get a green again.

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 25-year traffic projections.

RCUTs have also been proven to improve 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. 

Example Signal Timings
  • These charts show an example of the proportion of each signal cycle dedicated to each movement (i.e. green time for that movement.)
  • Cycle time for both is equal.
  • Up/down arrows are north/south Bandera Rd.
  • Current timing splits are approximate as they change during the day, but are typical.
  • RCUT timings are an example to illustrate how combining the turning movements into a single phase using the longest previous phase duration frees-up time for the remaining Bandera Rd. through-traffic phase without changing the overall cycle length. It is possible-- and even likely-- that the proportion of time allocated to the turning movements could be increased to improve throughput while still providing increased green time for Bandera Rd. through traffic.
  • Finally, in an RCUT, the signals on each side of Bandera Rd. can be timed independently of the other, so the RCUT chart below combines both directions for simplicity.

Current
RCUT

Superstreet For a deeper explanation on how an RCUT functions and how it improves traffic flow, see the main Restricted Crossing U-Turn intersections page.


Flyover and boulevard proposals

As with previous flyover proposals, the more recent flyover proposals generated controversy in Leon Valley. Chief among the concerns of many leaders and citizens there is that a flyover would speed traffic through the suburb and, it is asserted, would speed drivers past the businesses along Bandera, thus negatively affecting them. These businesses, of course, comprise an outsized portion of that city's tax base, so their concern is understandable. (Of course, congestion also negatively impacts those businesses, perhaps even more than a flyover would. Research shows a 10% reduction in average travel speeds in a corridor can result in a 20% loss of market area for nearby businesses.) Additionally, there was great concern about the aesthetics of an elevated road, specifically are that it would be unsightly and create a visual barrier that would divide the city and negatively impact property values. There was also angst about the noise that an elevated road would generate.

With the flyover proposal causing consternation, Leon Valley enlisted the assistance of UTSA's Center for Urban and Regional Planning Research and the Institute for Economic Development to look at options for Bandera that could reduce congestion without the harmful effects. After researching other concepts, they developed a proposal for what is known as a "multi-way boulevard." As envisioned, this would be a 10 lane at-grade thoroughfare with signalized intersections in the same locations as today. The 10 lanes would include three main through lanes in each direction with two parallel frontage lanes on each side. The frontage lanes would be built in the area used today for the drainage culverts on the side of the road and would be physically separated from the through lanes by landscaped traffic islands. Just like the frontage roads along a freeway, the frontage lanes in this concept would provide access to adjacent properties and would be the location for sidewalks, bus stops, and bike lanes. Traffic would move between the through lanes and frontage lanes via slip ramps located between intersections, much like the entrance and exit ramps from access roads to freeways.

Boulevard cross section
Cross-section of proposed boulevard concept


There are several examples of multi-way boulevards in the US including Queens Blvd. and Ocean Pkwy. in New York City, Octavia Blvd. in San Francisco, and Bothell Way in Bothell, Washington. There is even a smaller-scale example here in San Antonio: Verano Pkwy. on the Texas A&M-San Antonio campus on the South Side. All of these examples include on-street parking, however, which the Bandera proposals would not.

The report listed the expected benefits of the boulevard concept as follows:
  • By isolating slower local traffic to the frontage lanes, traffic in the through lanes can move faster and more safely.
  • With 10 lanes, the corridor would have about 66% more lane capacity than today.
  • The boulevard would be landscaped with trees and other foliage, making the corridor more pleasant and inviting especially for pedestrians and cyclists.
  • Because there are no elevated structures, a boulevard would be much less obtrusive than an elevated highway, thus minimizing visual and sound impacts.
While the flyover proposal would require about 11 acres of additional right-of-way, the boulevard proposal would require about 30 acres of additional right-of-way.

In addition to traffic, access, and aesthetic considerations, UTSA's Institute of Economic Development was asked to study the effect an elevated road might have on property values. Unfortunately, there's a dearth of direct data on the subject. However, data was available on the impact when elevated freeways were torn-down. This data showed that doing so resulted in a substantial increase in adjacent property values. Based on that, UTSA's researchers extrapolated that building an elevated expressway through Leon Valley would result in an equally inverse decrease in property values.

(COMMENTARY: That seems to be an overly simplistic inference as there are many other variables and factors that would likely have played into those increases. To be fair, it would require much more extensive study to identify and control for those factors. But it is also well-known that improved access typically leads to an increase in property values. Furthermore, my own cursory analysis of several random properties in the shadow of the current flyover in the vicinity of Bandera and Wurzbach show that almost all of them increased in value over a five year window at roughly the same rate as other properties further down Bandera in Leon Valley. Again, to be fair, I was not able to compare the property values immediately before and after the flyovers were built nor to do an extensive analysis. In closing, normally I would present the study's findings without editorial, but I felt these points needed to made. Your mileage may vary.)

There is also evidence that increasing the walkability of an area increases adjacent property values.

UTSA's researchers admitted that the boulevard proposal, while adding capacity, is not likely to solve congestion issues, which TxDOT's subsequent analysis and modeling confirmed. Instead, it makes improvements while further considering additional transportation modes, adjacent land uses, and economic impacts. In conjunction with the boulevard plan, UTSA's team also emphasized the need for expansion of other nearby roadways as well as the overall road network itself.

As an interesting footnote, this is not the first time a boulevard plan has been proposed as an alternative for this general corridor. A proposal for a Bandera/Culebra expressway in the 1970s was met by a counter-proposal from San Antonio Mayor John Gatti for an "avenida", a concept described as a wide boulevard with bus lanes.




Animation illustrating both the "flyover" and boulevard proposals.
This is at Bandera and Huebner looking north.
(Courtesy of UTSA and the City of Leon Valley)

Renderings
Below are selected renderings 
created by UTSA of both the flyover and boulevard proposals. These renderings are only for illustrative purposes and don't represent any actual plans. A sincere thank you goes to the UTSA Center for Urban and Regional Planning Research and the City of Leon Valley for making these available.




Bandera and Seneca: Flyover




Bandera and Seneca: Boulevard




Bandera and Seneca: Flyover




Bandera and Seneca: Boulevard




Bandera and Huebner: Flyover




Bandera and Huebner: Boulevard




Bandera and Huebner: Flyover




Bandera and Huebner: Boulevard




Bandera and Eckhert: Flyover




Bandera and Huebner: Boulevard



FAQ

Below are some frequently-asked questions and comments about this corridor.

  • RCUTs looks confusing. They will cause lots of crashes.
    This is always one of the first knee-jerk 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 (RCUTs) 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".

  • 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 shorter or at least no longer than 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.

  • This will increase emergency response times in the area.
    TxDOT will work with the City of Leon Valley to mitigate concerns with response times. The initial proposal includes a special traversable median and actuated traffic signals for emergency vehicles at El Verde.

  • Why not build overpasses instead?
    Various flyover plans have been proposed over the years, but the City of Leon Valley has been and continues to be opposed to such plans. Therefore, engineers have had to look at alternatives. Across the country, traffic engineers have discovered that innovative intersections like RCUTs can produce good congestion relief and safety at a fraction of the cost and construction time of flyovers and other traditional grade-separated solutions. 

  • Why are there signals to leave the RCUT turnarounds?
    This is to prevent slower moving vehicles from entering the faster traffic stream and causing conflicts that could result in collisions or congestion. 

  • 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.

    An RCUT intersection was built at Bandera at FM 1560 South in Helotes in 2018, and two more RCUT intersections are under construction in Helotes. Unlike the 281 and 1604 RCUTs, which were built as short-term fixes, the RCUTs in Helotes are considered a long-term solution.

    RCUTs have also been constructed on a segment of Loop 337 in New Braunfels, and they are planned for Loop 1604 from US 90 to Macdona Lacoste Rd.

  • I heard that the US 281 "superstreet" was removed was because it was not working well, so why build one here?
    There had been plans to upgrade US 281 in that area 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, 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 traffic patterns and expected future traffic volumes on US 281 exceed what RCUTs can optimally handle, so they would never have been planned as a permanent solution there. While projected 2047 traffic volumes on some sections of Bandera are at the upper end of what RCUTs would typically be expected to handle, modeling shows that they should still be able to provide substantial congestion relief, and interim volumes for many years will be in the "sweet spot" for RCUTs to provide dramatic congestion reduction.

  • Who came up with this cockamamie design? This won't work and is just a waste of money.
    The RCUT design has 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 improvments, 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 improvements from conventional expansions 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.
  • Why can't they just synchronize the traffic signals on Bandera? This would fix the problem.
    Actually, the signals on Bandera are already part of a coordinated system and are optimized. Many people think that just synchronizing (coordinating) signals is a magic solution to all congestion. While in many situations it can and does provide substantial benefits, the fact is that coordinated signals can only provide improvements up to the point where traffic volumes on a road reach the saturation point, and then the laws of physics (space and time) take over. Bandera well exceeds the saturation level at many times of the day.

    The way that signal coordination works is by breaking traffic into groups ("platoons") and moving them through the corridor at a set speed so that they hit each signal green along the way. The gaps between platoons are then used to allow green time for cross-traffic and left turns. When traffic volumes on a roadway reach saturation, the number of vehicles is greater than a reasonable amount of green time at each intersection can clear on each cycle. Then more vehicles stack up behind those as the gaps between platoons fill-up with vehicles turning onto Bandera from cross streets and driveways. On many urban arterials, the volume of traffic turning onto and off of a specific roadway
    at each intersection often is fairly balanced, so the platoon gaps stay somewhat stable and therefore signal coordination works better. But the intersecting road network along the Bandera Road corridor doesn't allow this and instead forces high volumes of traffic to turn onto Bandera at one intersection and then leave Bandera at a downstream intersection (see the map near the top of this page.) These "interlopers" consume most or all of the green time at the next downstream signal that was intended for the next platoon of through traffic to use. This results in part or even all of the following platoon getting stopped, making it seem like the signals aren't synchronized. With each cycle, the process repeats and the backups compound.

    Here's another way of explaining it. Imagine the signals on northbound Bandera at Grissom turn green and about 100 vehicles go through before it turns red again. We'll call this "Group 1". As those vehicles approach the Poss intersection, the signal turns green and stays green long enough allow those 100 vehicles through before turning red again, and so on for each intersection downstream. The process repeats then with Group 2, 3, etc., and everything is good.

    Now imagine that after Group 1 goes through the Eckhert intersection and the light turns green for Eckhert, 50 vehicles turn onto Bandera. They'll get stopped
    at Mainland when the light turns red behind Group 1, so there are now 50 vehicles waiting at Mainland. When the 100 vehicles in Group 2 reach that intersection, there will then be 150 vehicles wanting to get through, but since the signal is timed for a platoon of about 100, the 50 who arrived earlier from Eckhert will go and then only about 50 vehicles from Group 2 will make it through, leaving the last 50 waiting. Then, behind them, 50 more vehicles turn onto Bandera from Eckhert. That 50, plus the 50 from Group 2 that didn't get through, means there will then be 100 vehicles waiting at Mainland. Then the next 100 vehicles from Group 3 arrive, and now there are 200 vehicles wanting to get through at Mainland, but only the first 100 (the 50 leftovers from Group 2 and the 50 from Eckhert) will get through, meaning none from Group 3 will make it through.

    For those in Group 3, it now seems like the signals aren't synchronized since they have to stop and wait through a cycle. But it's not because the signals aren't synchronized that they didn't get through, it's because additional traffic "stole" their allotted time at Mainland. And as you can see, with every cycle, those numbers will keep compounding until the volume of traffic entering the corridor decreases below capacity.

    So couldn't they just extend the green time at Mainland to account for the additional vehicles from Eckhert? Sure, up to a point, but not much because doing so increases the red time on Mainland and for the southbound left turn, and longer red time of course means additional delays and congestion for the drivers on those approaches. And this example was only demonstrating how just one intersection can inject enough traffic to break the synchronization. Don't forget that even more traffic is going to turn onto Bandera from Grissom, Poss, Huebner, and the many driveways along the way, so each subsequent intersection downstream would need to have progressively more green time to accommodate each additional cohort of interlopers. This would eventually result in the downstream signals on Bandera having to be green constantly or nearly so in order to allow all that traffic through. That is obviously not a realistic solution. Alternatively, less traffic could be allowed through the Grissom intersection to offset the traffic turning on at Huebner and Eckhert, but that would just cause even longer backups there and therefore is also not practical.

    This example shows the limitations of signal coordination. When this situation happens, the traditional solution is to upgrade the corridor to a freeway. However, a freeway is not politically tenable on this corridor and would require significant new right-of-way. Thus, non-conventional solutions are needed.

  • Why did they build the flyovers at Loop 410? They don't really help and were a waste of money.
    As is often the case, this perspective ignores the bigger picture. The flyovers at Loop 410 take the heaviest traffic movement at that location and remove it from two already-congested signalized intersections. While traffic coming from Loop 410 to Bandera regularly backs-up during the afternoon rush hour, it does so out of the way of the surface intersections. More importantly, before the flyovers were built, that traffic nearly always backed-up onto the Loop 410 mainlanes, which was a dangerous situation. Now, that traffic is stored safely out of the way. Meanwhile, traffic headed the other way enjoys a good five minutes or more of time savings during the morning rush hour. When Bandera through Leon Valley is improved, commuters going from Loop 410 to Bandera during the afternoon rush hour will enjoy the full potential benefits of the existing flyover. While congestion at that location may make it seem like the flyovers don't help, the point that's often forgotten is this: how much worse would the congestion there be without the flyovers?

  • The existing flyovers have caused several nearby businesses to go under.
    I am only aware of one business that has claimed it was harmed by the flyovers. Regardless, there is no objective data (to my knowledge) to support that claim. It could have been a case of that business already having difficulties that were exacerbated by the traffic changes, or, perhaps, the flyovers are being used as a scapegoat. The other established businesses in the area seem to be doing fine. Regardless, congestion is at least equally detrimental to businesses if not more so, so improvements need to be made. While nobody wants to see businesses fail, there will, unfortunately, always be trade-offs whenever a major change is made, and attempts are made to minimize those impacts.

  • Traffic has been bad on Bandera for decades-- why hasn't anything been done?
    As mentioned above, several attempts have been made over the years to improve Bandera,
    including adding flyovers at major intersections and an elevated tollway, but the City of Leon Valley vetoed all of the proposals due to fears that those plans would hurt local businesses, which would have a serious impact on the city. New leadership in Leon Valley in recent years has recognized the need for improvements and has indicated a willingness to find solutions, but there's still a long road ahead (pun intended.) A new comprehensive planning effort that includes TxDOT and the cities of Leon Valley and San Antonio is now underway with all parties agreeing to the preferred solution.


Acknowledgments

Special thanks to the following for their assistance in providing information about these proposals:


Additional information

TxDOT - SH 16 (Bandera Road) from I-410 to Loop 1604
https://www.txdot.gov/projects/projects-studies/san-antonio/sh16-bandera-road-i410-loop1604.html
City of San Antonio - Bandera Road Corridor Plan
https://www.sanantonio.gov/planning/bandera-road-corridor-plan


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