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

This page last updated September 10, 2023

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 94 mile loop is non-freeway, most of which is a two-lane rural road.

Length (freeway section): 39 miles


On this page

Lanes Access
 Speed limits 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:
    • At the railroad tracks between FM 78 and FM 1976
    • 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

Generally, volume is moderate to heavy along entire route. 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. for a time. However, that has moderated substantially during the past decade (mainly due to capacity constraints), although most of the western arc has continued to see substantial growth during that time. After current expansion projects are complete, traffic counts will likely surge along the northern arc once again.

Recurring congestion occurs during morning peak periods eastbound between Culebra Rd. and I-10 West, westbound from Shaenfield Rd. to SH 151, and most of westbound Loop 1604 across the North Side. In the evenings, recurring peak period congestion occurs westbound from US 281 North to Bandera Rd., southbound from Shaenfield Rd. to SH 151, eastbound from the UTSA area to Bitters Rd., and eastbound from US 281 North to I-35 North.

LOCATION 2002 2012 2017 2019 2021 2022 '12-'22
E of FM 78 23,000 31,000 41,129 41,903 40,724 43,030 +38.81%
W of FM 78 43,000 55,000 67,174 67,555 61,928 61,606 +12.01%
S of Pat Booker Rd. 59,000 64,000 67,020 62,190 79,271 78,128 +22.08%
N of Pat Booker Rd. 59,000 72,000 98,853 102,231 84,141 82,167 +14.12%
W of I-35N 67,000 91,000 123,230 126,780 111,655 110,652 +21.60%
N of Lookout Rd. 67,000 91,000 116,417 123,206 103,520 101,808 +11.88%
N of Nacogdoches Rd. 58,000 88,000 111,072 113,497 92,035 91,556 +4.04%
W of O'Connor Rd. 69,000 88,000 112,228 118,185 111,204 109,716 +24.68%
E of Gold Canyon Rd. 86,000 105,000 121,579 126,300 126,961 115,802 +10.29%
W of US 281N 104,000 120,000 125,989 131,146 100,343 125,841 +4.87%
E of Bitters Rd. 85,000 113,000 161,000 164,218 154,706 116,008 +2.66%
W of NW Military Hwy.         127,585 125,360 N/A
W of Vance Jackson Rd. 85,000 128,000 142,249 146,905 126,819 119,379 -6.74%
W of I-10W 71,000 113,000 131,409 134,730 116,488 112,733 -0.24%
N of Hausmann Rd. 61,000 100,000 114,499 116,399 101,084 104,741 +4.74%
N of Bandera Rd. 59,000 100,000 122,687 136,161 108,092 110,080 +10.08%
S of Bandera Rd. 41,000 83,000 89,976 102,305 115,987 120,361 +45.01%
S of Braun Rd.         108,514 112,745 N/A
N of Culebra Rd. 24,000 74,000 97,685 119,406 128,082 130,444 +76.28%
S of Culebra Rd. 29,000 85,000 86,833 115,180 131,343 129,333 +52.16%
S of SH 151         75,535 72,309 N/A
N of Potranco Rd. 19,300 34,000 33,664 31,528 45,023 42,774 +25.81%
S of Potranco Rd.         67,160 63,280 N/A
N of US 90W 16,300 26,000 27,402 41,185 45,285 45,557 +75.22%
(NOTE: In 2021, TxDOT changed the location of several traffic counting stations. New stations will show no history prior to 2021, and discontinued stations will show no history for 2021 or thereafter.)

Construction projects

  • I-35 to FM 78: Click here for details on this project.
  • Bandera Rd. to I-10: 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, and ground was broken on the first segment-- from US 281  to I-10 on the North Side-- on August 4th, 1960. Most of the northern half was built as new "greenfield" 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. The initial plan for the loop was to build a "starter" two-lane road, then come back later and expand to a four-lane divided highway, and the state acquired plenty of right-of-way for those future expansions.

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 assigned a one to three digit number, this should have resulted in a new number being assigned. But the route number 1604 had already become so ingrained with area residents that state officials decided to simply switch the route prefix 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.
  • 1961: The section between I-10 West and US 281 North is completed as FM 1604, followed by the segment from I-10 West to Bandera Rd.
  • 1963: The segment from US 281 to Bulverde Rd. was completed.
  • 1967: The sections from Bandera Rd. to Culebra Rd. and from Bulverde Rd. to Pat Booker Rd. are completed.
  • 1969: The segment from Pat Booker Rd. to I-10 East is completed as well as the section from Culebra Rd. to US 90 West.
  • 1970: The section from US 90 West to Macdona Lacoste Rd. 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.
  • 1977: The route designation is changed from FM 1604 to Loop 1604 and FM 1518 from La Vernia Rd. to SH 16 South is incorporated into the loop.
  • 1978: The segment from I-10 East to La Vernia Rd. is opened, officially completing the loop.
  • 1980: The section of FM 1518 from SH 16 South to I-37 is straightened and improved.
  • 1981: The section of FM 1518 from I-37 to La Vernia Rd. is straightened and improved.
  • 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.
  • 1995: The freeway section from US 281 to Redland Rd. was completed.
  • 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. 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.
  • 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. The section from Shaenfield Rd. to Guilbeau Rd. is upgraded to a "superstreet" as an interim measure to ease congestion while funding for an upgrade to a freeway was pending.
  • 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.
  • Late 2012: The flyovers in Phase 1 of the US 281/Loop 1604 interchange open.
  • 2013: The overpass at Vance Jackson Rd. is completed.
  • 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.
  • 2016: The freeway lanes from Braun Rd. to SH 151, the flyover from southbound Loop 1604 to SH 151, and the overpass from SH 151 to Alamo Ranch Parkway all opened.
  • 2018: MPO votes to remove toll lanes from planned expansion from Bandera Rd. to I-35 after additional state funding for the project is forecast.
  • 2019: The section from SH 151 US 90 West was upgraded to a four-lane freeway and the flyover from southbound Loop 1604 to eastbound US 90 opened.
  • 2020: Flyovers from southbound US 281 to Loop 1604 open.
  • 2021: Flyovers from Loop 1604 to northbound US 281 open. The segments from I-10 East to Martinez Creek and from US 281 South to FM 1303 were expanded to a four-lane divided highway.
  • 2022: The section from Pat Booker Rd. to FM 78 was upgraded to a full freeway.

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 on a new alignment was designated FM 1604, and segments were added to it over the years as they were completed. When the loop nearing completionin 1977, the route prefix was changed from FM to Loop, but it kept the number 1604 as it was well-known locally. 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. 

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

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