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

This page last updated November 30, 2018

Loop 1604 highlight map This page covers the freeway segment of Loop 1604 across North San Antonio from FM 78 in Converse to SH 151. The remainder of the 95 mile loop is non-freeway, most of which is a two-lane rural road.

Length: 31 miles


On this page

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


When it was 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 in its original configuration as a two-lane rural state highway, 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 Randolph AFB, Rolling Oaks Mall, the Stone Oak area, Camp Bullis, 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 headquarters for Valero Energy and Andeavor Energy, the Alamo Ranch area, Sea World, 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 with some moderate to heavy commercial development, especially near I-35, US 281, I-10, Bandera Rd., and SH 151. The area outside 1604 from Bandera Rd. to US 90 is expected to add 200,000 people by 2030.

There is only half of a fully directional interchange at US 281. Motorists must use access roads and a signalized three-level interchange to access US 281 north of 1604. Work to construct the remaining four ramps of the interchange is underway and expected to be complete by 2020. Cloverleaf interchanges exist at I-10 and I-35. At SH 151, there is a flyover connector from southbound Loop 1604 to eastbound SH 151. Another flyover connector is under construction from southbound Loop 1604 to US 90 eastbound.

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

Roadway details


    • 4 lanes along entire route


Loop 1604 access roads map
  • Continuous access roads along all of route except:
    • East of Pat Booker (NB) and east of Kitty Hawk (SB)
    • At I-35
    • At the railroad tracks between Nacogdoches and Green Mountain

Click here for a list of Loop 1604 exits.



Loop 1604 speed limit map
  • 70 mph from Nacogdoches to SH 151
  • 65 mph from Pat Booker to FM 78


Loop 1604 special features map
  • TransGuide coverage from Lockhill-Selma to SH 151
  • Five at-grade turnoffs ('right-on, right-off") with no median crossover in Universal City
  • Partial directional interchanges at US 281 and SH 151 
  • 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 with average AADT counts up well over 300% along nearly the entire route, and up nearly 800% near Bandera Rd. However, that has moderated substantially during the past decade. Generally, volume is moderate to heavy along entire route. Traffic on the section north of Bandera Rd. increased more than tenfold between 1990 and 2015. Recurring congestion occurs during morning and evening peak periods between Bandera Rd. and US 281.


LOCATION 1990 2006 2010 2014 2015 2016 '06-'16
E of FM 789,40027,00026,00030,17432,51040,095+48.50%
W of FM 7818,30027,00056,00054,66058,81165,992+144.41%
Pat Booker Rd.19,80073,00065,00065,01079,46990,720+24.27%
Lookout Rd.21,00082,00081,00096,437100,656114,064+39.10%
Green Mountain Rd.15,80089,00070,00081,61394,987107,829+21.16%
O'Connor Rd.16,80087,00078,00092,47593,113105,332+21.07%
Gold Canyon Dr.19,800114,00096,00094,187101,873112,556-1.27%
W of US 281N24,000127,000118,00095,27399,204109,760-13.57%
Bitters Rd.25,000108,000107,000112,593136,275144,265+33.58%
Tradesman Dr.26,000113,000108,000112,871129,500136,224+20.55%
La Cantera Pkwy.21,00094,000113,00070,875119,668126,313+34.38%
Hausmann Rd.13,30077,00095,000104,141105,328111,597+44.93%
N of Bandera Rd.10,20076,00094,000102,971105,721111,970+47.33%
S of Bandera Rd.8,70080,00065,00076,85181,11473,221-8.47%
N of Culebra     71,863N/A
S of Culebra     98,874N/A

Construction projects

  • At SH 151/Alamo Ranch Parkway: Click here for details on this project.
  • Culebra to Potranco: Click here for details on this project.
  • At Bandera: Click here for details on this project.

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

Future plans

Plans were announced in early 2017 to make upgrades to the section from I-35 to FM 78. These upgrades will include constructing continuous access roads to connect the existing stretches of discontinuous access roads and eliminate the several "right-on, right-off" intersections on the mainlanes, reconfiguring existing entrance and exit ramps, adding auxiliary lanes between ramps, and reconstructing the Pat Booker overpass. Construction could begin in 2018. More details here.

In 2018, plans were announced to upgrade the section from FM 78 to I-10 East to a full freeway, possibly starting in 2023.  Details of those plans are here.

Plans have been in the works since 2005 to expand Loop 1604 from Bandera to I-35 by adding tolled managed lanes in the median between the existing lanes. The environmental study for that project, however, has been delayed several times over the years due to changes in its scope (it initially included the section all the way south to US 90) and funding issues with the study itself. In August 2018, with new transportation funding available and tolling deprecated, the MPO removed the toll component of this project. TxDOT now plans to expand 1604 from Bandera to I-35 to eight general purpose lanes (i.e. four in each direction) and one HOV lane in each direction. Before work can start, the environmental study needs to be completed. Funding for first phase-- from Bandera to Redland-- has been identified and TxDOT estimates that construction might begin as early as 2021. That phase will also include some of the flyovers for a new interchange at I-10. Funding for the second phase-- from Redland to I-35 and the remainder of the new flyovers at I-10-- will need to be found before work can be scheduled on it.

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.

Loop 1604 was assembled from several Farm-to-Market and State Loop roads in the early '60s. One of the FM roads that was included was FM 1604, and segments of other roads added to the loop were subsequently renumbered as FM 1604. When the loop was completed in 1977 and state officials were ready to change the designation from FM to Loop, the term "Loop 1604" had already become so ingrained with area residents that they decided to simply change the route designation to Loop 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 in Irene, Texas, east of Hillsboro. Regardless, many locals still mistakenly refer to Loop 1604 as FM 1604.

Loop 1604 usurped all or parts Loop 334, FM 1518, FM 1604, FM 1627, and FM 2173. FM 1518 ran from Somerset east to Elmendorf, then north to near US 87 and then on to Schertz. FM 1627 was a short road connecting I-35 to Pat Booker, and FM 2173 connected Somerset to Macdona. Loop 334 composed the western arc of today's 1604 routing from I-10 West south to Macdona.

The first plans for an outer loop around San Antonio emerged in 1956. Soon after, work began on the first segment of FM 1604 from I-10 to US 281 and was completed around 1958. By 1964, it had been extended to I-10 East. Meanwhile, to the west, Loop 334 was being built from the end of FM 1604 at I-10 West. That route reached south to the Bandera Road area by 1958. It was renumbered to be part of FM 1604 in 1959 and reached Macdona ca. 1974. FM 2173 and 1518 were upgraded and redesignated as FM 1604 in the mid '70s, and the missing section, between I-10 East and FM 1518, was built in the late '70s.

During the early '80s, the northern and western sections of 1604 were known as the "death loop" due to a high number of fatal accidents along the increasingly busy two-lane roadway.

The current interchange at I-35 was completed in 1986 and the interchange at I-10 was completed in 1987. Also around 1987, the section between US 281 and I-10 was upgraded to a four-lane freeway. The section between US 281 and I-35 was upgraded to a freeway in three phases between 1988 and 1991. The section from I-35 to FM 78 was upgraded ca. 1991. The segment from I-10 to Babcock was upgraded in 1992. The section from Babcock to Braun Rd. was completed in 1996. The section from Braun Rd. to near Culebra was upgraded to a divided highway in 1999, and the overpass at Culebra opened in mid 2004. TransGuide coverage was added to the section between Babcock and Tradesman in 1999. The previously-missing access roads between NW Military and Bitters were added during the summer of 2002. TransGuide coverage was extended to the section from I-10 to Bandera Rd. in April 2003. Work to upgrade the section from SH 151 south to US 90 from a two-lane rural road to a four-lane divided highway was completed in 2007 and work to widen the section from FM 78 to Lower Seguin Rd. to a divided highway was complete in September 2011. Work to upgrade the section from Lower Seguin Rd. to I-10 East to a four-lane divided highway was completed in 2015.

TxDOT and the Alamo Regional Mobility Authority released plans in June 2007 for 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-10W, US 281N, I-35N, and I-10E, as well as modifications and improvements on those intersecting roads. That project was eventually broken-up into smaller, toll-free projects.

In 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. This project built all four of the ramps connecting to 281 south of 1604, i.e. northbound 281 to both directions of 1604, and both directions of 1604 to southbound 281. The use of the federal funds allowed the ramps to be toll-free. The Texas Transportation Commission (TTC) approved the funding request on March 5th, 2009. Construction began in early 2011 and the first ramps opened on November 8, 2012, with the remainder opening a few days before Christmas that same year. The remainder of the improvements associated with the interchange project, including additional lanes on 1604 and some ramp modifications, were all complete by mid 2013.

An overpass for Vance Jackson Rd. was completed in mid 2013.

In 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. The new southbound freeway lanes opened to traffic on April 23, 2016, followed by the northbound lanes on May 12, 2016. The flyover from SB Loop 1604 to SH 151 opened to traffic July 30, 2016 and the SH 151 - Alamo Ranch Parkway overpass opened on December 17, 2016.

In 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. Work began on that segment in late 2016. For more information on the Culebra to Potranco segment, click here. For the Potranco to US 90 segment, click here.


  • Is it "Loop" 1604 or "FM" 1604?
    It is Loop 1604. A Loop designation is equivalent to a State Highway, which makes it eligible for more types of funding than FM roads are. There is actually an FM 1604 in the town of Irene in North Texas.

  • Why is Loop 1604 the only four-digit loop in Texas?
    As the loop was being built, the state used the number of one of the existing roadways that became part of the loop-- FM 1604-- as it was extended. Once the loop was completed in 1977 and the designation was ready to be changed to "Loop", the term "Loop 1604" had already become well used among locals, so the designation simply changed from FM to Loop. It is an exception to Texas' numbering rules and is one of just four four-digit state highways that's not an FM road.

  • Why are the new sections of Loop 1604 only four lanes? It needs to be six lanes or more.
    The number of lanes for a new roadway is based on current and projected traffic volumes for the next 20 years. Twenty years is the accepted planning horizon for a couple of reasons. First, 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). Second, that length of time is the longest that any projections can be considered even remotely reasonable. Since nobody has a crystal ball, traffic projections are "educated guesses" based on the best data available for future development in an area and past growth. Roads are then planned based on those projections. In the case of the new segments of Loop 1604, those projections show that four lanes will be adequate for the 20 years. TxDOT, as a steward of taxpayer dollars, cannot spend more than they can justify, a policy I'm sure most taxpayers support, especially with all the other needs that need to be funded.

  • 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 35 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. The issue now is that an upgrade is needed 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 over a decade. However, such an expansion is a very expensive project-- approaching $1 billion. Due to substantial funding shortages in the early 2000s, TxDOT was required to plan to use tolling to pay for the new lanes. 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 has since been removed from the project. This will require the project to be redesigned yet again and will also require additional funding to be found in order to complete it. As of this writing, TxDOT anticipates starting work on the first phase-- from Bandera to Redland-- could start in 2021.

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This page and all its contents are Copyright 2018 by Brian Purcell

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