Home | About me | Contact | What's new | Privacy | Search

San Antonio
Freeway system
  Fwy system history
  2022 traffic statistics
  The freeways
    I-10 East
    I-10 West
    I-35 North
    I-35 South
    Kelly Pkwy
    Loop 410 (I-410)
    Loop 1604
    SH 151
    Spur 371
    US 90 West
    US 281 North
    Wurzbach Pkwy
  Construction projects
    I-10E Exp (Graytown)
    I-10E/Loop 410
    I-10 Boerne area
    I-35 Comal Projects
    I-35 NEX
    Loop 410/SH 151
    Loop 410/US 281
    LP 1604N Expansion
    LP 1604/Blanco
    LP 1604/FM 78-I-10
    LP 1604/I-35-FM 78
    SH 151 Expansion
    US 90W Expansion
    US 90/Loop 410
    US 281N Expansion
    US 281 Comal Exp
    US 281/Basse
    US 281/Jones-Mltsbrg
    Wurzbach/NW Military
    HOV lanes
    Media galleries
    Tollway system
    10/1604 yield signs
    History of 281/410
Other roads

Search this site

This site is not affiliated with any official agency.

Buy Me a Coffee at ko-fi.com

If you found this site informative, please consider giving a small tip to help support it. Thanks!


San Antonio Area Freeway System
PROJECT INFO: Wurzbach Pkwy at NW Military

This page last updated March 15, 2022


Project locationLocation
Wurzbach Pkwy from Bluffton Oaks to Elm Creek


Construction started in August 2020 and is complete.

This project made improvements the Wurzbach Parkway intersections at NW Military Hwy. and Lockhill-Selma Rd.

At NW Military, the project added a second dedicated left turn lane and converted the existing optional left/through lane to a dedicated through lane on all approaches (i.e. all four approaches now have two dedicated left turn lanes and three through lanes.) All of the left turn movements have been configured to allow for simultaneous opposing left turns. A second right turn lane from westbound Wurzbach to northbound NW Military has been added, and the signals are being optimized for the new configuration.

The eastbound to westbound turnaround on Wurzbach Pkwy. has been moved slightly further to the west to better accommodate the expanded left turn lanes from northbound NW Military.

Between NW Military and Lockhill-Selma, a third westbound lane has been added and the pedestrian path in the center median has been removed.

At Lockhill-Selma, an additional through lane for Wurzbach has been added in both directions. The right westbound through lane has become a right-turn-only lane at Elm Creek (i.e. through traffic has to merge to the left to continue on Wurzbach.)

A signal on NW Military at Turnberry Way/Fairfield Bend Dr. was studied but ultimately not included in the final plan. Engineers will monitor the area after the project is complete.

A previous proposal to build an underpass for Wurzbach at NW Military and a SPUI intersection was cancelled after public feedback (see history section below for more details.)

How this project will help
The additional lanes will provide additional capacity for turns and through traffic.

At NW Military, re-orienting the left turn movements to allow for simultaneous operation allows the left turns to be handled separately from the through movements. This will facilitate significantly more efficient signal operation because left turn green time can be terminated when the queue has emptied, thus allowing for additional green time for opposing through traffic without increasing the overall cycle length. The previous intersection configuration and its inherent four-way signal operation did not permit this, which caused very inefficient and "unbalanced" signal operation that was the primary cause of  recurring congestion.

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.

Planners always evaluate multiple options for any project to determine which alternative best addresses the need at the most reasonable cost. Normally, I don't present all the options studied for a project. For this project, however, I will because the initial preferred option was scuttled by opposition from adjacent neighborhoods, resulting in an alternate-- and likely less effective in the long-term-- option being eventually selected after an extended public-involvement process (and almost certainly some behind-the-scenes political muscling due to certain prominent nearby residents.)

The original proposal presented to the public in 2016 was for a Single Point Urban Interchange (SPUI) at the NW Military intersection. This option would have built an underpass for through traffic on Wurzbach and would have configured the surface-level intersection as a SPUI. The primary opposition to this plan was that through traffic would not be possible on the new access roads that would be created along Wurzbach Parkway. There is little need for through access roads at this location since the adjacent neighborhoods and shopping center have direct access onto NW Military, which facilitates any movements that would be lost by blocking through traffic on the access roads at NW Military. But residents in the adjacent neighborhood deemed that too inconvenient, preferring instead to maintain their existing travel patterns at this intersection via their neighborhood access points on Wurzbach. (In hindsight, those access points should never have been built. They were provided in exchange for right-of-way donation for Wurzbach. Once access is given, it's much harder to take away later.)

Given that, and an assortment of other objections posed by constituents regarding trees, downstream impacts at Lockhill-Selma, and various temporary construction impacts, TxDOT re-opened the evaluation process and proffered a smorgasbord of options for public consideration including several alternative intersection designsAfter several stakeholder meetings with the nearby HOAs and residents, as well as the general public, the less-ambitious conventional improvements plan-- with some additional modifications-- was finally selected.

That said, the option that was finally chosen does offer good short to mid-term improvement, especially for the cost. It is not likely, however, to provide durable benefits in the long-term.

The options evaluated are listed below. A brief description along with an expected benefit rating (one to four "+" signs with four indicating the best overall improvement for traffic) and cost rating (one to four "$" signs with four indicating the highest relative cost) are included for each. The projects are ordered generally from highest benefit to lowest. All of the options included identical changes to the Lockhill-Selma intersection, and those were included in the final plan.

  • Single Point Urban Interchange (SPUI) [ ++++ | $$$$ ]
    As mentioned above, this was the original proposal for this project. An underpass for Wurzbach would have been built with exit and entrance ramps for NW Military. The signalized intersection on NW Military would have been configured as a SPUI with no through traffic on the Wurzbach access roads. For information on how a SPUI works and its benefits, see the alternative intersections page.

  • Modified SPUI [ +++ | $$$$ ]
    This is the same as the SPUI proposal above but with through lanes included on the access roads. Doing this decreases the signal efficiency since it requires an additional phase per cycle. With the same cost as a regular SPUI, the decreased efficiency of the signals caused the cost/benefit ratio for this option to drop appreciably.

  • Diverging Diamond Interchange (DDI) [ +++ | $$$ ]
    This option is similar to the SPUI option above but would have built a Diverging Diamond Interchange (DDI), similar to the one currently under construction at Blanco at Loop 1604, instead of a SPUI. As with the SPUI proposal, there would have been an underpass for Wurzbach Parkway and no through traffic on the Wurzbach access roads. For information on how a DDI works and its benefits, see the alternative intersections page.

  • Conventional diamond interchange/full underpass [ +++ | $$$ ]
    This plan would have built an underpass for Wurzbach through traffic and a conventional diamond interchange, i.e. the standard freeway/access road type interchange found everywhere. The four-phase signal operation for this type of interchange is the same as what is there today, but the decrease in traffic on the Wurzbach approaches provided by the underpass was still not enough to make this the most efficient option, especially given the cost.

  • Conventional diamond interchange/partial underpass [ ++ | $$ ]
    This is the same plan as above except that only eastbound Wurzbach would have an underpass; westbound Wurzbach traffic would still go through the signalized intersection. This option was included to compare the impact on traffic at Lockhill-Selma against the previous option. While it did decrease congestion there (because westbound traffic is "metered" here), it resulted in a very imbalanced signal operation here, which made it much less effective.

  • Displaced Left Turn (DLT) [ ++ | $$ ]
    This option would have built a displaced left turn intersection similar to the one at Bandera and Loop 1604. Left turns from Wurzbach to NW Military would shift to the opposite side of the road upstream of the intersection. The through lanes on Wurzbach would be squeezed together in the existing median area to provide room for those left turn lanes.
    There would be no underpass in this plan. For information on how a DLT works and its benefits, see the alternative intersections page.

  • Median U-Turn (MUT, aka a "Michigan Left") [ + | $ ]
    This proposal would have eliminated left turns in all directions at the NW Military intersection. Instead, left-turning traffic would use new turnarounds constructed downstream on Wurzbach. This is
    known as a "Michigan Left" intersection and is similar to the Restricted Crossing U-Turn (RCUT) intersections built in recent years at several locations around the area except that through traffic would be allowed on both Wurzbach and on Military. By eliminating left turns, the signals operate with just two phases, the most efficient operation available. For information on how a MUT works and its benefits, see the alternative intersections page.

  • Conventional intersection improvements [ + | $ ]
    This option only makes conventional improvements to the existing at-grade intersection; it does not include an underpass. The plan shown below is an early version of the plan that was finally selected. This plan differs from the final proposal in the way it handles left turns from NW Military onto Wurzbach. In this plan, the intersection was not configured to allow for simultaneous left turns from NW Military, which reduces intersection efficiency. The final plan adds a second dedicated left turn lane for each direction of NW Military and utilizes the left turning configuration of a SPUI, thus allowing simultaneous left turns and wringing the most possible efficiency out of this plan. This proposal also adds a third through lane to both directions of Wurzbach, extends the right turn lanes, and adds a second right turn lane from westbound Wurzbach to northbound NW Military; these elements were all included in the final plan.

This page and all its contents are Copyright 2023 by Brian Purcell

The information provided on this website is provided on an "as-is" basis without warranties of any kind either express or implied.  The author and his agents make no warranties or representations of any kind concerning any information contained in this website.  This website is provided only as general information.  The author expressly disclaims all liability with respect to actions taken or not taken based upon the information contained herein or with respect to any errors or omissions in such information.  All opinions expressed are strictly those of the author.  This site is not affiliated in any way with any official agency.