San
Antonio Area Freeway System
I-35
Northeast Expansion (NEX) Project |
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This
page
last updated September 9, 2020 |
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This
project is currently in design
The
descriptions below are based on preliminary
schematics and,
as
a
result, details may change before the project goes to construction.
This project will be built using a design-build contract, so final
plans will not be available before construction starts. However, they
aren't expected to differ substantially from what is described below. |
TxDOT
has been studying an expansion of I-35 from downtown San Antonio to the
Schertz area since the mid '90s. For much of the past decade,
those plans necessarily included tolled lanes. But with the deprecation
of tolling statewide in the past few years, the toll component of this
expansion has been removed and TxDOT is
now planning to expand I-35 by adding
non-tolled express lanes and HOV lanes from AT&T
Center Pkwy. to FM 1103. The new lanes will be elevated
(double-decked) south of FM 3009 and be at-grade
from there
to FM 1103.
Below
is complete information about the latest status of this project.
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On
this
page
Current project plans
Background
In 1996, a Major
Investment Study of the I-35 northeast corridor recommended
barrier-separated express lanes, truck lanes, and/or HOV lanes.
However, acute funding shortages in the early 2000s caused this plan to
be shelved. In 2009, the Alamo Area Regional Mobility Authority (ARMA)
resurrected the plan as a secondary phase for a local tollway
system.
Under this plan, the new lanes would have been built as tolled managed
lanes.
That plan proposed two express lanes in each direction with connectors
to Loop 1604, Loop 410 North, and Loop 410 South. As the
plan was further fleshed-out, it was determined that the new
lanes would have to be elevated along most of the route from downtown
to the FM 1103 area due to right-of-way constraints. The
environmental study for that project was
completed and approved in 2015.
Around
that time, tolling became deprecated both locally and statewide as the
legislature and citizens approved new funding sources for highways. As
a result, the various local planned toll projects were successively
"de-tolled" as new funding sources were identified for them. Tolls were
removed from the I-35
project in June 2018.
With
the toll
component removed, TxDOT began work redesigning the project without
tolls.
Additionally, recent local transportation policy changes have promoted
the addition of HOV lanes to freeway expansion projects where feasible.
Given the length and commuting patterns of
this corridor, as well as an already impressive 10% carpooling rate,
HOV lanes were determined to be a good fit and so were added to the
project.
Project description
This nearly $3 billion project will add non-tolled express
lanes and HOV lanes on about 16 miles of I-35 from AT&T
Center Pkwy. to FM 1103. The new lanes will be elevated
(double-decked) south of FM 3009 and be at-grade
from there
to FM 1103. There will be two express lanes in each direction from
AT&T Center Pkwy. to Rittiman Rd., two express lanes plus an
HOV lane in each direction from Rittiman Rd. to the Bexar county
line, one
express lane and one HOV lane in each direction from Schertz Pkwy to FM
3009, and one new general-purpose mainlane and one HOV lane in each
direction from FM 3009 to FM 1103. The
project will also build new interchanges above or near the existing
interchanges to connect the upper level lanes to Loop 410 South, Loop
410 North, Loop 1604, and Pat Booker Rd., as well as an intermediate
access point to and from the I-35 mainlanes at the Bexar county line,
and make some incidental changes along those routes to accommodate the
new interchange ramps. The existing interchanges at those locations
will remain as they are.
Cross-section from AT&T
Center Pkwy. to Rittiman Rd.

Cross-section from Rittiman Rd.
to Bexar county line

Cross section from Bexar county
line to FM 3009

Cross section from FM 3009 to FM
1103

NOTE
Number of access road lanes varies depending on location.
Diagrams are for illustrative purposes only and are not to scale.
Unlike
the double-decked freeways downtown, the upper levels on this project
will be express lanes,
meaning there will be limited entrances and exits between FM 1103 and
downtown San Antonio. The
intent for the new lanes is to
provide an express facility for longer-distance through traffic in the
corridor, but this will also benefit the lower
level by removing that long distance traffic from those lanes.
In
addition to the north and south ends, motorists will also be
able
to enter or leave the elevated lanes at the following locations:
- Bexar
county line:
- Southbound
entrance from I-35 mainlanes to express lanes
- Northbound
exit from express lanes to I-35 mainlanes
- Loop
1604
- Connectors to/from
Loop 1604
- Pat
Booker Rd.:
- Entrance
from Pat Booker to southbound express lanes
- Exit from
northbound express lanes to Pat Booker
- Ramps
located on Pat Booker between I-35 and Loop 1604
- Loop
410 North:
- Connectors to/from
Loop 410
- Loop
410 South:
- Connector from Loop 410 to
northbound express lanes
- Connector
from southbound express lanes to Loop 410
- Southbound
exit from express lanes to I-35 access road

Crossovers
between the two upper levels will be provided for
emergency access
at three locations in the corridor: between Eisenhauer and
Walzem, near O'Connor, and near Olympia Pkwy.
The
project will also include several ramp revisions to accommodate the
access and egress locations for the new elevated lanes. It will also
add turnarounds at Schertz Pkwy. and make
intersection
improvements and build
new overpasses at
Wiederstein Rd. and at FM 2252.
Timeline Current
funding constraints will require the project to be divided
into
multiple
phases. Initially, funding was only available for the middle section
from Loop 410
North to FM 3009, including the new connectors to Loop 410 North and
to Loop 1604 to the west of I-35. In August 2019, the Texas
Transportation Commission approved additional funding for the southern
section from Walters St. to Loop 410 North. The
remaining segment-- from
FM 3009 to FM 1103, as well as the connectors to Pat Booker Rd. and to
Loop 1604 east of I-35-- are currently unfunded.
This
project will be built using a design-build
contract, which means that
TxDOT will select a contractor who will complete the final design of
the project and construct it. This process generally results in time
and cost savings.
PHASE 1: Loop
410 North to FM 3009
-
Status: Funded
- Timeline:
Expected to start construction in mid to late 2021 with estimated completion
in 2026
- Cost:
About $1.62 billion
This phase will
include the following:
- Two
elevated express lanes and one HOV lane in each direction
- Elevated
connectors to Loop 410 North just south of the existing interchange
- Elevated
connectors to Loop 1604 west of I-35
- Upper levels for this phase will end at the future intermediate access point at the Bexar county line
- Emergency
crossovers for the elevated lanes near O'Connor Rd. and Olympia Pkwy.
- Additional
lanes on Loop 410 to provide access to and from the new elevated lanes
- Ramp
revisions on eastbound Loop 410 from Nacogdoches to Perrin-Beitel to
accommodate the new interchange ramp and smooth traffic flow approaching
it
PHASE 2:
Walters St. to Loop 410 North
-
Status: Funded
- Timeline: Currently expected to start construction in 2025 with estimated completion in 2029
- Cost:
About $905 million
This phase will
include the following:
- Two
elevated express lanes in each direction from AT&T
Center Pkwy. to Rittiman Rd.
- Two
elevated express lanes and one HOV lane in each direction from Rittiman
Rd. to Loop 410 North, including connectors to Loop 410
- Elevated
connectors to and from Loop 410 South near Rittiman Rd., terminating
near FM 78
- Southbound exit to I-35 access road north of George Beach
Ave.
- Ramp
revisions on southbound I-35 between Rittiman Rd. and George Beach Ave.
- Emergency
crossover for the elevated lanes between Eisenhauer Rd. and Walzem Rd.
PHASE 3: Bexar
county
line to north of FM 1103.; Pat Booker Rd./Loop 1604 East interchange
-
Status: Unfunded
- Timeline:
No timeline pending funding
- Cost:
About $417 million
This phase will
include the following:
- One elevated express lane and one HOV lane in each
direction from Bexar county line to FM 3009
- One additional mainlane and one HOV lane in each direction
from FM 3009 to FM 1103
- Widened overpasses at Wiederstein Rd. and FM 2252
- Ramp revisions between FM 3009 and FM 1103
- New turnarounds at Schertz Pkwy.
- Elevated
connectors to Loop 1604 east of I-35
- Elevated connectors to Pat Booker Rd.
- Changes to Pat Booker Rd. between Loop 1604 and I-35 to
accommodate new ramps
How this project will help
This corridor experiences frequently-recurring congestion due to
traffic volumes regularly exceeding the capacity of the road.
A study of
the corridor in the 1990s determined that a significant
percentage of the traffic is passing all the way through the corridor
or traveling between the major interchanges, and
recommended barrier-separated express and/or truck lanes to segregate
that traffic from the local traffic. Those travel patterns
continue today, and so the new elevated express lanes should
remove most
of that through traffic-- including a lot of truck traffic-- from the
existing mainlanes below, thus reducing congestion
there. It is estimated that when the first
phase is complete, travel time on the existing mainlanes between the
Bexar county line and Loop 410 North will be cut in half from about 20
minutes to less than 10 minutes. When the entire project is complete,
the travel time between FM 1103 and AT&T Center Pkwy. is
estimated to be reduced from about 45 minutes to less than 20 minutes.
HOV
lanes are now being added to major freeway expansion projects where
feasible. The intent is to encourage carpooling and use of mass
transit. Each person that opts to do so is one less vehicle on the
freeway, which helps to reduce congestion and pollution for everyone. A
study of this corridor showed an impressive 10% of commuters
were already carpooling, a number that should increase with the
provision of an HOV lane. For more information about local HOV lanes, see the HOV lanes page.

Rendering of proposed northbound elevated lanes near George Beach Ave.
Schematics
Click on one of the areas on the map below to open the
detailed schematics for that section of the project. The base
schematics are from TxDOT with my own annotations added to help clarify
and
explain the various elements. Each schematic will
open in a new window that you can scroll and zoom. These
are the schematics presented to the public in August 2019 and are still considered preliminary and subject to change.
On
the schematic, any elevated segments colored in blue are Phase
1 (called the "base" sections in the legend.) The sections colored in
green south of Loop 410 (schematics C and D) are Phase 2.
The sections colored in green north of the Bexar county line and
east of I-35 at Loop 1604/Pat Booker Rd. (schematics A and B) are Phase 3. (See phase details
above.) Other improvements shown in different colors will
typically
be done in the corresponding phase of the adjacent elevated
section.

FAQ Also see the HOV FAQ on the HOV lanes page.
- Will
this project be tolled?
No. Although earlier versions of this project proposed adding managed toll lanes,
funding was secured to remove the toll component. Instead, non-tolled
express lanes and HOV lanes will be added.
- Why
are they building expensive elevated lanes instead of a more
conventional at-grade widening?
The existing right-of-way along most of the corridor is inadequate for
a
traditional widening, and because of the extensive development along
the frontage roads, the cost to acquire the needed right-of-way would
be more expensive-- and disruptive to the businesses and neighborhoods
along the corridor-- than building the elevated lanes.
- Why
aren't there more entrances and exits from the elevated lanes?
A study of the corridor in the 1990s determined that a
significant percentage of the traffic is passing all the way through
the corridor or traveling between the major interchanges, a
pattern that hasn't changed much today. Therefore, the
intent of the new elevated lanes is to
provide an express corridor for that traffic-- including a lot of truck
traffic-- thus removing it from the
existing mainlanes below. Since that traffic is traveling
longer-distances, they don't need those intermediate entrances and
exits, and additional entrance and exits would increase the traffic
volumes on those elevated lanes, defeating their purpose.
Also, providing those additional entrance and exits would
require
additional right-of-way, which is limited in this corridor. This same
concept is used on the I-35 elevated lanes in Austin, the Katy Freeway
express lanes in Houston, and the Dan Ryan express lanes in Chicago,
among others.
- The
lack of entrances and exits will hinder emergency response and will
trap traffic on the upper level if a crash blocks all the
lanes.
To
improve access for emergency vehicles and provide an "escape route" for
trapped traffic, emergency crossovers will be constructed at three
locations in the corridor: between Eisenhauer Rd. and Walzem Rd., near
O'Connor Rd., and near Olympia Pkwy. This same approach has been used
on other long dual-span roads that have limited or no access, most
notably in Louisiana on I-10
over the Atchafalaya Swamp and on the two bridges over Lake
Pontchartrain.
- I
will not use/can't access the elevated lanes, so how will
it benefit me?
Traffic that uses the elevated lanes will not be on the mainlanes
below, so this will reduce congestion there. It is estimated that when
the first phase is complete, travel time on the existing mainlanes
between the Bexar county line and Loop 410 North will be cut in half
from about 20 minutes to less than 10 minutes.
Other
sites of interest
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