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Loop 1604 San Antonio Area Freeway System
State Loop 1604 (Charles W. Anderson Loop)

This page last updated March 23, 2021

Loop 1604 highlight map This page covers the freeway segment of Loop 1604 across North and West San Antonio from FM 78 in Converse to US 90 West. The remainder of the 95 mile loop is non-freeway, most of which is a two-lane rural road.

Length (freeway section): 39 miles


On this page

(Not yet available)
Lanes Access
Special features
& notes
Traffic Media gallery
History FAQ


When the first segments were built in the 1960s, it would have been hard to fathom that Loop 1604 North would become the busy beltline that it is today. While the southern half remains mostly in its original configuration as a two-lane rural state highway (for now), the northern arc has been expanded to a four-lane freeway.

Loop 1604 forms the outer of San Antonio's two beltways and the freeway portion serves Joint Base San Antonio Randolph and Camp Bullis, the Forum and Live Oak Town Center shopping centers, Rolling Oaks Mall, the Stone Oak area, the University of Texas at San Antonio's (UTSA) main campus, Six Flags Fiesta Texas, the Shops at La Cantera and the La Cantera development, The Rim development, the corporate headquarters campuses for Valero Energy and NuStar, the Alamo Ranch area, Sea World and the Westover Hills area, and the suburban cities of Converse, Universal City, Live Oak, Selma, Hollywood Park, Shavano Park, and Helotes. The corridor runs through increasingly dense suburban residential areas interspersed with moderate to heavy commercial development, especially at the main nodes near I-35, Bulverde Rd., US 281, Blanco Rd., I-10, Bandera Rd., Culebra Rd./SH 151, and Potranco Rd. The area outside 1604 from Bandera Rd. to US 90 is expected to add roughly 200,000 people between 2020 and 2030.

A five-level "stack" interchange exists at US 281 with cloverleaf interchanges at I-10 and I-35. There is a single flyover connector from southbound Loop 1604 to eastbound SH 151 as well as from southbound Loop 1604 to US 90 eastbound.

Loop 1604 is sometimes mistakenly referred to as FM 1604.  However, FM 1604 is in North Texas.  (See the History section below for more info.)

Roadway details


    • 4 lanes (2 x 2) along entire route


Loop 1604 access roads map
  • Continuous access roads along all of route except:
    • Northbound between Kitty Hawk Rd. and Pat Booker Rd. (under construction)
    • Between Kitty Hawk Rd. and FM 78 (under construction)
    • At I-35
    • At the railroad tracks between Nacogdoches Rd. and Green Mountain Rd.
    • Northbound through the SH 151 interchange

Click here for a list of Loop 1604 exits.



Loop 1604 speed limit map
  • 70 mph from Nacogdoches Rd. to US 90 West
  • 65 mph from Nacogdoches Rd. to FM 78


Loop 1604 special features map
  • TransGuide coverage from Lockhill-Selma to US 90 West
  • Partial directional interchanges at SH 151, and US 90 West 
  • VIA Metropolitan Transit University Park & Ride located under I-10 interchange
  • Carpool parking area on northbound ramp to/from FM 78
  • Unusual yield sign arrangement at I-10 interchange; click here for more information


Loop 1606 traffic map
Traffic volume legend

Loop 1604 experienced ridiculously blistering traffic growth during the 1990s and early 2000s with average 10-year traffic counts up well over 300% along nearly the entire route, and up nearly 1000% near Bandera Rd. However, that has moderated substantially during the past decade, although most of the western arc, as well as the eastern end, have continued to see substantial growth over the past decade. Generally, volume is moderate to heavy along entire route. Recurring congestion occurs during morning and evening peak periods between Bandera Rd. and US 281.

LOCATION 1999 2009 2014 2017 2018 2019 '09-'19
E of FM 78 18,500 27,000 30,174 41,129 41,157 41,903 +55.20%
W of FM 78 35,000 49,000 54,660 67,174 67,555 67,555 +37.87%
S of Pat Booker Rd. 45,000 75,000 65,010 67,020 62,190 62,190 -17.08%
N of Pat Booker Rd. 45,000 75,000 51,980 98,853 102,305 102,231 +36.31%
W of I-35N 55,000 88,000 96,437 123,230 128,717 126,780 +44.07%
N of Lookout Rd. 55,000 88,000 96,437 116,417 123,309 123,206 +40.01%
E of Green Mountain Rd. 48,000 76,000 81,613 111,072 113,497 113,497 +49.34%
W of O'Connor Rd. 60,000 83,000 92,475 112,228 118,240 118,185 +42.39%
E of US 281N 75,000 104,000 94,187 121,579 126,300 126,300 +21.44%
W of US 281N 102,000 127,000 95,273 125,989 131,146 131,146 +3.26%
E of Bitters Rd. 84,000 118,000 112,593 161,000 167,336 164,218 +39.17%
Vance Jackson Rd. 86,000 117,000 112,871 142,249 146,600 146,905 +25.56%
W of I-10W 66,000 113,000 70,875 131,409 136,605 134,730 +19.23%
N of Hausmann Rd. 52,000 99,000 104,141 114,499 117,426 116,399 +17.57%
N of Bandera Rd. 50,000 95,000 102,971 122,687 124,665 136,161 +43.33%
S of Bandera Rd. 37,000 71,000 76,851 89,976 89,215 102,305 +44.09%
N of Culebra Rd. 18,300 61,000 76,907 97,685 113,746 119,406 +95.75%
S of Culebra Rd. 21,000 79,000 97,235 86,833 109,787 115,180 +45.80%
N of Potranco Rd. 15,400 27,000 32,629 33,664 33,503 31,528 +16.77%
N of US 90W 14,300 22,000 24,225 27,402 33,009 41,185 +87.20%

Construction projects

  • I-35 to FM 78: Click here for details on this project.

Click here to view information for all projects in this corridor.

Future plans

In 2018, plans were announced to upgrade the section from FM 78 to I-10 East to a full freeway, now estimated to start after 2030. Details of those plans are here.

Plans had been in the works since 2005 to expand Loop 1604 from Bandera Rd. to I-35 by adding tolled managed lanes in the median between the existing lanes. The environmental study for that project, however, was delayed several times over the years due to changes in its scope caused by the unexpected availability of funding for toll-free expansions in the western corridor and, later, due to funding shortages for the study itself.

In August 2018, with new transportation funding available and tolling deprecated, the MPO removed the toll component of the planned expansion from Bandera Rd. to I-35. TxDOT now plans to expand 1604 from Bandera Rd. to I-35 to eight general purpose lanes (i.e. four in each direction) plus one HOV lane in each direction. Funding for first construction three projects stretching from Bandera Rd. to US 281 has been secured with construction planned to start in phases between mid 2021 and mid 2022. One of those three projects will replace the cloverleaf at I-10 with a new five-level "stack" interchange. Funding for the remainder-- from US 281 to I-35-- has not yet been secured.

TxDOT plans to expand all of Loop 1604 south of US 90 to a four-lane divided highway. The first project is now complete with a second one nearing completion. Two more projects are expected to start in the next decade.

Loop 1604 For more information on the planned expansion of Loop 1604 North, see the Loop 1604 North Expansion Project page.


Loop 1604 was authorized by Transportation Commission Minute Order 72928 (June 30, 1977). Named "Anderson Loop" for former Bexar County Judge Charles W. Anderson who advocated for an outer loop during the mid 1950s. Anderson served as Bexar County Judge from 1939 until his death in 1964.

The first plans for an outer loop around San Antonio emerged in 1956. Most of the northern half was built as new route while most of the southern half usurped the existing routes of FM 2173 and FM 1518. As those southern sections were incorporated into the loop, improvements were made such as straightening some of the more crooked sections and building bypasses at Somerset, Elmendorf, and Lone Oak.

Loop 1604 was originally planned to be numbered Loop 26. In 1958, the western arc of today's Loop 1604, from I‑10 south to Macdona, was reportedly planned to be numbered Loop 334. However, the first sections of the loop to be built were instead numbered FM 1604. When the loop was nearing completion in 1977, state officials were ready to change the designation from FM to Loop. Because loops are typically not assigned a four-digit number, this should have resulted in a new number being assigned.  However, the route number 1604 had already become so ingrained with area residents that state officials decided to simply switch the route designation from FM to Loop, keeping the route number as 1604. As a result, Loop 1604 is the only four-digit loop and one of just four four-digit state highways in Texas that is not a Farm-to-Market road. The FM 1604 designation has since been recycled and is in use on a short route in Irene, Texas, east of Hillsboro. Regardless, many locals still continue to (incorrectly) refer to Loop 1604 as FM 1604.

In the late '70s and most of the '80s, the northern and western sections of Loop 1604, which were still mostly two-lane farm road, became known as "The Death Loop" due to a high number of fatal accidents.

The opening dates below up to 1981 are for the original two-lane rural road.
  • 1956: The general route that is Loop 1604 today appears in the master expressway plan for Bexar County.
  • 1960: The section between I-10 West and US 281 North is completed as FM 1604.
  • 1961: The segment from I-10 West to Bandera Rd. is completed.
  • 1967: The sections from Bandera Rd. to Culebra Rd. and from US 281 North to Pat Booker Rd. are completed.
  • 1969: The segment from Pat Booker Rd. to I-10 East is completed.
  • 1970: The section from US 90 West to Macdona Lacoste Rd. is completed.
  • 1971: The section from Culebra Rd. to US 90 West is completed.
  • 1973: FM 2173 from Macdona Lacoste Rd. to Somerset and FM 1518 from Somerset to SH 16 South is improved and renumbered as FM 1604.
  • 1975: The section from I-35 North to FM 78 is expanded to a four-lane divided highway.
  • 1978: The segment from I-10 East to La Vernia Rd. is completed. At this point, the loop is essentially complete with a stretch of FM 1518 connecting the two ends of Loop 1604 at St. Hedwig and SH 16 South.
  • 1980: The section of FM 1518 from SH 16 South to I-37 is improved and renumbered as Loop 1604.
  • 1981: The section of FM 1518 from I-37 to La Vernia Rd. is improved and renumbered as Loop 1604. This was the final section of  road to become Loop 1604 and marked the official completion of the loop.
  • 1982: The first half of the cloverleaf interchange at I-10 West was completed.
  • 1986: The current interchange at I-35 North was completed.
  • 1987: The remainder of the cloverleaf at I-10 West was completed, and the section between I-10 West and US 281 North was upgraded to a four-lane freeway except for the overpass at Lockhill-Selma Rd., which was completed in 1991. 
  • 1988: The segment from I-35 North to Green Mountain Rd. was upgraded to a four-lane freeway.
  • 1989: The section from US 281 North to Redland Rd. was upgraded to a four-lane freeway except for the mainlanes and overpass at Gold Canyon Rd.; those were completed in 1995.
  • 1991: The overpass and interchange at Kitty Hawk Rd. was built and the segment between Kitty Hawk Rd. and Pat Booker Rd. was improved.
  • 1992: The sections from Redland Rd. to Green Mountain Rd. and from I-10 West to Babcock Rd. were upgraded to a four-lane freeway.
  • 1996: The segment from Babcock Rd. to Braun Rd. was upgraded to a four-lane freeway.
  • 1999: The section from Braun Rd. to near Culebra Rd. was expanded to a four-lane divided highway and TransGuide covereage was added to the section between Babcock Rd. and Tradesman Dr.
  • 2002: The access roads between NW Military Hwy. and Bitters Rd. were completed.
  • 2003: TransGuide coverage was extended from Babcock Rd. to Bandera Rd.
  • 2004: The overpass and interchange at Culebra Rd. was completed.
  • 2007: The section from SH 151 to US 90 West was expanded to a four-lane divided highway.
  • June 2007: TxDOT and the Alamo Regional Mobility Authority announced a $1.8 billion mega-project to upgrade and expand Loop 1604 across northern San Antonio from Military Dr. West around to I-10 East. This project would have added tolled freeway lanes where there were no freeway lanes (i.e. south of Braun Rd. and south of FM 78). Between Braun and FM 78, the project would have added new tolled managed lanes in the median between the existing free freeway lanes, which would have remained toll-free. Additionally, it would have built new interchanges at SH 151, I-10 West, US 281 North, I-35 North, and I-10 East. That project was eventually broken-up into smaller, toll-free projects.
  • February 2009: Congress approved a national economic "stimulus" plan that poured additional federal money into road construction projects. The Metropolitan Planning Organization (MPO) approved allocating San Antonio's share of transportation stimulus funding to be used as matching funds to leverage state funding for first half of a 281/1604 interchange.
  • 2011: The segment from FM 78 to Lower Seguin Rd. was expanded to a four-lane divided highway.
  • May 2012: Local officials identified funding to construct new toll-free freeway lanes from Bandera Rd. south to SH 151. After a funding swap to remove federal funding from the project, it was removed from the overarching federal environmental study for the corridor, which allowed the state to begin construction after a state environmental approval. After work began, the project was expanded to include an overpass for SH 151 to Alamo Ranch Parkway and a flyover from southbound Loop 1604 to SH 151.
  • November 8th, 2012: The first flyovers in the US 281/Loop 1604 interchange open.
  • December 2012: The remainder of the flyovers in the first phase of the US 281/Loop 1604 interchange open.
  • 2013: The overpass at Vance Jackson Rd. is completed.
  • January 2014: TxDOT and ARMA officials announced funding had been secured to extend the non-toll freeway south from SH 151 to US 90 and build an elevated direct connector from southbound Loop 1604 to eastbound US 90.
  • 2015: The section from Lower Seguin Rd. to I-10 was expanded to a four-lane divided highway.
  • April 2016: The southbound freeway lanes from Braun Rd. to SH 151 opened.
  • May 2016: The northbound freeway lanes from SH 151 to Braun Rd. opened.
  • July 2016: The flyover from southbound Loop 1604 to SH 151 opened.
  • December 2016: The overpass from SH 151 to Alamo Ranch Parkway opened.
  • April 2019: The section from SH 151 to Potranco Rd. was upgraded to a four-lane freeway.
  • June 2019: The section from Potranco Rd. to US 90 West is upgraded to a four-lane freeway and the flyover from southbound Loop 1604 to eastbound US 90 opened.

Loop 1604 north of Culebra Rd. looking south in 1988
(Image courtesy of TxDOT)

Loop 1604 at Green Mountain Rd. looking southeast in 1991
(Image courtesy of TxDOT)

Sign along Loop 1604 in 1983
(Image courtesy of TxDOT)


  • Is it "Loop" 1604 or "FM" 1604?
    It is Loop 1604. The first segment of what is now Loop 1604 to be built from scratch after it was first proposed was numbered FM 1604 and segments were added to it over the years. When the loop was completed, the designation was changed in 1977 from FM to Loop. Besides the obvious meaning of the "loop" nomenclature for motorists, a Loop designation is equivalent to a State Highway, which makes it eligible for more types of funding than FM roads. The FM 1604 designation was re-cycled in 1980 for use on a short stretch of road in the town of Irene in North Texas, where it is still in use today.

  • Why is Loop 1604 four digits while other loops in Texas are three or fewer digits?
    The first section of new route built for San Antonio's outer loop was originally designated as a farm-to-market road and numbered FM 1604. As the loop was being built, the new sections were built as continuations of FM 1604. Once the loop was completed in 1977 and the designation was ready to be changed to "Loop", the route number of 1604 had already become well used among locals, so they opted to keep the number 1604 and simply changed the designation from FM to Loop. It is an exception to Texas' numbering rules and is one of just four four-digit state roads that's not an FM road.

  • Why are the new sections of Loop 1604 freeway only four lanes? They need to be six lanes or more.
    A lot of people see the congestion on Loop 1604 North and assert that the new sections of Loop 1604 should to be wider to start with. However, those sections carry less than a third of the traffic that most sections of Loop 1604 North do (for example, 34,000 vehicles per day at Potranco vs. 123,000 at Bandera.) That current volume, and the projections for the next 20 years, indicate that four lanes should be adequate for those new sections. Twenty years is the accepted planning horizon because that's the length of time before a road will need major repairs and upgrades simply due to age (i.e. the road's expected lifespan), and because that's the length of time that any projections can be considered even remotely reasonable. Will those new sections experience congestion before 20 years? Maybe. Nobody has a crystal ball, so traffic projections are "educated guesses" based on the best data available for future development in an area and past growth, and road capacity is always theoretical-- many other factors other than just the number of lanes affect congestion levels. But as a steward of taxpayer dollars, TxDOT cannot spend more than they can empirically justify, a policy I'm sure most taxpayers support to prevent "pork" projects. And spending now on extra lanes that may or may not be needed in the future takes away funding for other projects that are needed today.

  • Why didn't they build Loop 1604 between Bandera and I-35 with more than four lanes?
    See the point above regarding how the number of lanes to be built is determined. Then keep in mind that Loop 1604 between I-10 and I-35 was planned nearly 40 years ago and that it was an upgrade from a two-lane rural road to the four-lane freeway that's there today-- a dramatic increase in capacity at the time. Loop 1604 between Bandera and I-10 was planned around 1990 and also was an upgrade from a two-lane rural road. In both cases, significant recurring traffic congestion didn't develop until the 15 to 20 year mark, which shows the validity of the planning done. An expansion has been planned for over a decade now but has been delayed (see next point.)

  • Why haven't they added more lanes to Loop 1604 North? Don't they know how bad the traffic is?
    Plans have been in the works to expand Loop 1604 from Bandera to I-35 for well over a decade. However, such an expansion is a very expensive project-- approaching $1 billion. Due to substantial funding shortages that began in the early 2000s, TxDOT was required to incorporate tolling to pay for mega projects like this. With local opposition to tolling and the drama over a similar plan on US 281 that delayed that project for over a decade, the plan for 1604 has had to be reworked several times. Additionally, because of the project's location over the Edwards Aquifer Recharge Zone, an extensive and lengthy Environmental Impact Study (EIS) is required. With new funding mechanisms now in place and tolling deprecated, the toll component was removed from the project, which required the project to be redesigned yet one more time and additional funding allocated in order to complete it. 

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This page and all its contents are Copyright 2019 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.