Texas
Highways Primer |
|
This page
last updated June 23, 2019 |
Texas
is a big
place. It's nearly 880 miles from the Louisiana border near
Orange to the New Mexico border near El Paso, and nearly 500 miles from
the Oklahoma border north of Dallas to the Mexican border in
Laredo. That size gives the state a tremendous amount of
diversity. A hot, humid sub-tropical climate in the Valley
yields
to a varying Midwest climate, complete with snow, in
Amarillo. There are Piney Woods in East Texas, desert and low mountains
in West
Texas, and plains,
prairies, and the Hill Country in between. The state has some
of
the nation's biggest metropolitan areas and some of its most desolate
ranges. With this size and diversity, a large and rapidly
growing
population, a booming economy, an increasing role in international
trade, and its overwhelming dependence on the automobile, Texas cannot
help but have the nation's biggest, most well-developed highway system
with nearly 80,000 miles of state-maintained roads.
This
primer is
designed to give you an overview of the state's highway system and its
idiosyncrasies. If you're looking for a route log, check out
Texas
Highway
Routes by David Stanek, a complete listing of all
highways in
Texas. Both Ron Jackson's TexasFreeway.com
and
Andy Field's LoneStarRoads
sites have
lots of in-depth information on freeways and other highways statewide.
On this page:
Some
Texas highway facts
Highways
in Texas
are managed by the Texas Department of Transportation
(TxDOT). TxDOT was created in 1991 from the former State Department of
Highways
and Public Transportation (SDHPT), which itself was created by the
merger of the Texas Highway Department and Texas Mass Transportation
Commission in 1975. After several earlier failed attempts, the original
Texas Highway Department was born in 1917, mainly as a prerequisite in
order for the state to receive federal highway funds. Prior to
that, counties were responsible for building and maintaining a system
of roads that connected county seats.
Here
are some basic facts about
the
state highway system in Texas:
CENTERLINE
MILES
(2017) |
 |
3,459 |
 |
11,851 |
 |
16,391 |
 |
40,849 |
 |
349 |
Frontage
Roads |
7,546 |
TOTAL
STATE SYSTEM MILEAGE |
80,444 |
TOTAL LANE MILES |
196,307 |
- REST
AREAS:
90
- ROADSIDE
PARKS: ~600
- FIRST
HIGHWAY: Started in 1918 and finished in 1920, between
Falfurrias
and Encino in Brooks County, along present day US 281
- FIRST
INTERSTATE: 1956, I‑45 (then US 75) near Corsicana in Navarro
County
- SHORTEST
HIGHWAY: Loop 168 in Tenaha, Shelby County, is 391 feet (.074
miles)
- LONGEST
HIGHWAY: US 83 stretches 899 miles from the Oklahoma state
line
near Perryton to the Mexican border near Brownsville
- HIGHEST
HIGHWAY: A spur from Texas 118 at the McDonald Observatory on
Mt.
Locke in West Texas is 6,791 feet above sea level
- BUSIEST
HIGHWAY: I-10/Katy Freeway in Houston just east of Beltway 8
carries 366,000 vehicles daily
- NUMBER
OF
BRIDGES: 54,180 (more than double the number of any other
state); 35,564 of those are on the state system
- LONGEST
BRIDGE: The Fred Hartman Bridge east of Houston is 2.6 miles
long
State-maintained
highways comprise about 26% of the total roadway mileage in Texas but
carry about 73% of all traffic.
Interstates
In
addition to
having the nation's largest highway system overall, Texas also has more
Interstate mileage than any other state. There are now 19 numbered
Interstate Highways in the state:
  

Texas
has two of the three "suffixed" Interstates in the nation. The
first, I‑35, is split into I‑35E
through Dallas and I‑35W through Ft. Worth. I‑69 is split
three ways: first, I‑69 splits into I‑69E and I69W at Victoria with
I‑69E running south to Brownsville along US 77 and I‑69W continuing
south to Laredo along US 59. I‑69C
then branches from I‑69W at George West and runs along US 281 south to
I‑2 at Pharr.

Texas
also has two "hidden" or unsigned Interstates: I‑345, which is
a short extension of I‑45 in downtown
Dallas, and I‑110, which connects I‑10 to the
Mexico border in El Paso.
Interstates
in
Texas were generally built by upgrading existing US or State
highways. I‑45 replaced US 75, I‑35 replaced US 81, and I‑40
replaced the famed US 66, to name a few. In urban areas, many
existing expressways were simply re-signed as Interstates. The
first Interstate contract let in Texas was for a segment of I‑45 in
Navarro County near Corsicana in 1956. The latest
additions
to Texas' Interstate inventory are I‑69, I‑2, and I‑14. (See the I‑69 and I‑14
sections below.) Prior to that, the
last Interstate to be completed was I‑27 between Lubbock and Amarillo
in 1992.
I‑35
from the
DFW Metroplex to San Antonio is the busiest Interstate corridor in
Texas with no fewer than 65,000 vehicles per day on its rural sections
between Hillsboro and Waco and higher counts as you go further south.
As a result, this entire corridor has been upgraded to six lanes over
the past two decades. A tollway to bypass Austin (SH 130) from
Georgetown to I‑10 at Seguin was completed
in 2012. TxDOT is also participating a $1.5
million
federal study of I‑35 from Laredo to Duluth, Minnesota, which aims to
provide comprehensive improvements to the corridor. (More
information on the I‑35 corridor between San Antonio and Austin is
available as part of my San
Antonio roads pages.)
In
addition to I‑35, TxDOT has projects underway or planned to widen the
other two legs of the
"Texas Triangle" (I‑10 between Houston and San Antonio and I‑45 between
Houston and Dallas) to six lanes over the next decade.
Besides
increases in passenger vehicles,
truck traffic on I‑35 and other Interstates has grown rapidly
as a result of the North American Free Trade Agreement (NAFTA) and a
resurgence in oil drilling in the state in the past decade.
Exits/entrances, the
ubiquitous frontage roads, and "Texas U-turns"
As you drive through Texas, you may notice that exits and entrances on
many of our Interstates tend to be at more frequent intervals than in
other
states. This is the result of the philosophy of Dewitt Greer, a
former long-time director of the state highway department. It
was
his belief that, given the vastness of the state, Interstates should
not just serve "interstate" traffic, but also "interregional" traffic
within Texas, and more frequent exits would help facilitate that.
Another
byproduct of this doctrine is perhaps the most unique feature of the
state's highway system: frontage roads. There are over 7,000
miles of these along freeways in Texas, which is more-- much more--
than any
other state. Instead of using new rights-of-way, many
Interstates in Texas were built along the routes of existing US
highways. Since Interstates have limited access, the state would
have had to pay to acquire the access rights of frontage properties
when upgrading an existing road to an Interstate. It was
decided that it would cheaper to build frontage roads to
keep access to those adjacent
properties instead of acquiring the rights, not to mention the
political expediency of doing to. As a result, this quickly
became standard
operating
procedure at the Highway Department (and subsequently TxDOT) and a
large percentage of the state's freeways were built under this policy.
In
June
2001, the Texas Transportation Commission considered a major policy
change that would have eliminated frontage roads from any new freeways
unless
absolutely necessary. This rocked many Texans to their core-- enough so
that the commission
decided to scrap the idea.
There
are
several ramp configurations used with frontage roads. The
"diamond" interchange is typical, with the on- and off-ramps
connecting to the frontage roads in the general shape of a diamond
relative to the cross street (see illustration below).
Sometimes, the ramps are reversed in an "X"-interchange
with the exit ramp for the next cross street preceding the entrance
ramp from the previous cross street. This is generally the
new
standard in urban areas as it typically improves safety, reduces exit
ramp backups onto the main freeways lanes, provides
better
access
to and from frontage properties, and
helps reduce
through traffic at the the frontage road
intersections, thus improving
their operation. Occasionally, if space is limited, both the on and off
ramps
are
built at the same location in a "braided" arrangement where one ramp
passes-over the other.

Frontage
roads with diamond interchanges |
|

Frontage
roads with "X" interchanges |
Speed
limits on
frontage roads generally range from 50-60 mph in rural areas and 40-50
mph in urban areas. In urban areas, frontage roads are
typically one-way
in
the same direction as the adjacent freeway lanes. In rural
areas
they are generally two-way. By law, traffic
leaving
or entering the freeway has the right-of-way over traffic already on
the frontage road.
The
ubiquitous
frontage roads have another interesting cultural facet-- as you travel
through the state, you may notice that people in each of the regions
call their frontage roads something different. For
example, in Houston and East Texas,
they're known as "feeder" roads; in Dallas-Ft. Worth, they're "service"
roads; in San Antonio, they're "access" roads; and in El Paso,
they're called "gateways". The term generally used
in Austin
and the state's official term is "frontage" road, which is how you'll
see them marked on guide signs statewide, even in the aforementioned
areas where the popular vernacular differs. Indeed, what someone calls
the roads next to the freeway is a good shibboleth to determine
where they're from within the state.
It
should be
noted that frontage roads (or whatever you call them) are not just
found on Interstates-- you'll find frontage roads on freeways
regardless of route classification (i.e. Interstate, US, or SH routes).
Native
Texans are
frequently surprised when they go to other places and find no frontage
roads. A comment many make after their trip to another
state is, "they don't
have frontage roads on their highways!" But many native
Texans don't
realize how much of an idiosyncrasy our extensive frontage roads
are. Conversely, many out-of-state visitors immediately notice and
comment
on our frontage roads (with no clear majority observed by this author
between thumbs-up
and thumbs-down.)
Going
hand-in-hand with frontage roads are the so-called "Texas U-turns" or
"turnarounds". These are separate U-turn lanes that allow
traffic
heading in one direction on a one-way frontage road to reverse course
and head the other way on the opposite frontage road without having to
pass through the two frontage road/cross street intersections (see
diagram
below). This reduces congestion and conflicts in those
intersections. Where the cross street passes under the freeway, the
turnaround is typically in the same underpass. Where the cross street
passes over the freeway, turnarounds can either share the same overpass
as the cross street (physically separated from the main road)
or have their own separate overpasses. Turnarounds
are only used on
one-way
frontage roads and therefore are generally found only in urban
areas. Like frontage roads, these may have different names in
different parts of the state although "turnaround" seems to be the
predominate term. Most of the state uses the "U-turn ONLY"
sign
to mark them, although the "turnaround" sign is used in some places.
Other terms used for
turnarounds are "U-turn lane" and "crossover", although the later more
correctly describes an opening in the median on a divided highway.

Turnaround
diagram

Typical
turnaround in San Antonio
Exit numbers
Texas, like most states, switched from a sequential exit numbering
system to a milepost numbering system in the mid to late '70s and early
'80s. The exit number was typically posted on a tab above the
exit board, but starting in 2012, signs with the exit number
incorporated on the main exit sign began
appearing.
"IH"
Another semantic idiosyncrasy is how TxDOT abbreviates
"Interstate". In most other states, it's I‑35, I‑10,
etc. Here, TxDOT's official term is "IH", as in IH-35 or IH-10, with
"IH"
being short for "Interstate Highway". Furthermore,
depending which part of the state you're in, you may hear locals using
that
term as well. (As you can tell by my pages,
I prefer "I" myself.) I believe TxDOT uses "IH" because all
of
their other highway abbreviations are two letters as well, so using IH
fit into that standard.
Interstate 69 and Interstate 2
With the
growth of NAFTA traffic, Texas began making plans in the late '90s
for its segment of Interstate 69 running from Texarkana through
Houston and on to
Laredo and the lower Rio Grande Valley. During
the first decade of this century, planning for this
route was rolled-into the Trans-Texas Corridor as "TTC-69" (more
details on the TTC below),
and "Future
I‑69" signs began appearing on US 59 in the Houston area in
2000. However,
after the demise of the TTC, the I‑69 project was continued as a
standalone effort.
I‑69
will upgrade the existing US 59 corridor, one of several corridors
being
strained by burgeoning NAFTA traffic. South of
Victoria, I‑69 forks into two routes: I‑69E along US 77 south to
Brownsville and I‑69W, which continues south along US 59 to Laredo.
Near George West, another branch, numbered I‑69C, splits off
of I‑69W and follows US 281 south to Pharr.
In
August 2011,
the Federal Highway Administration approved Texas' request to sign the
first section of I‑69 in the state and, four months later, the first
I‑69 signs
went
up on a 6.2 mile section of the US 77 expressway between I‑37 and
Robstown just west of Corpus Christi. Those first signs
were I‑69, but were later changed to I‑69E. In September 2012,
35
miles
of US 59 stretching from Loop 610 in northeast Houston to the
Montgomery/Liberty county line was also signed as
I‑69. Since then, numerous additional sections have been
signed as they have been upgraded to Interstate standards and, as of
2019, there were about 200 miles of I-69 signed in Texas.
As
part of the I‑69 project, the federal government also approved signing
US 83
through the Rio Grande Valley-- which was already at Interstate
standards-- as I‑2, connecting I‑69C at Pharr with
I‑69E at Harlingen.
More
information on I‑69 in Texas is available at the Alliance for I‑69
Texas
website.
Interstate 14
In
December 2015, the US Congress passed legislation that approved the
designation of another new Interstate in Texas, I‑14. Nicknamed
the "Forts-to-Ports" route, this
route was proposed
by the Gulf Coast Strategic Highway Coalition and is intended to
provide a high-speed east-west corridor through the middle of the state
connecting Ft. Bliss, Ft. Hood, and Ft. Polk in Louisiana and
connectivity via
other existing highways to the
military ports in Beaumont
and Corpus Christi. I‑14 is planned to subsume most of the
current
route of US 190 from West
Texas to the Louisiana border east of Jasper, connecting Brady,
Killeen, Belton, Bryan, Huntsville, and Livingston. Some
portions
of the route have not yet been finalized including the section from
Bryan to Huntsville and the routing west of Brady.
While
the
official designation currently calls for I‑14 to join with I‑10 in West
Texas,
planners are looking at possibly routing it northwest from Brady
through San Angelo to Midland/Odessa. As with I‑69, it is
possible that both legs may eventually be built. Also like
I‑69,
I‑14 will be built piecemeal by upgrading segments of
the corridor
to Interstate standards as funding becomes available.
The
first signs for
I‑14 were installed in April 2017 along the existing US 190 freeway
between Copperas Cove and I-35 at Belton.
More
information on I‑14 is available at the Gulf
Coast Strategic Highway Coalition
website.
Interstate 27 extension
TxDOT commissioned a study
during the mid '90s to investigate
extending I‑27 south from Lubbock. Three corridors were
considered: US 87/SH 349 to Midland, a Sweetwater-San Angelo-Junction
corridor connecting to I‑10, and another corridor through Big Spring to
I‑10 at Ozona. The study concluded that there was not enough
traffic at that time, or projected, to warrant an extension of I‑27 for
the
foreseeable future. Instead, a package of
upgrades to US 385, SH 349, US 87, and US 84 was recommended.
Over
the years, additional studies have been done on this
"Ports-to-Plains" corridor. Those reports have also concluded that ,
while there is support from many stakeholders for an Interstate, an
upgrade to a full Interstate is still not warranted in this corridor.
Instead,
various options including bypasses, intersection improvements,
additional lanes on existing roads, and ITS measures were
recommended. You can
read more at the Ports-to-Plains
coalition
website.
During
the 2019 legislative session, a bill was passed and later signed into
law that directed TxDOT to once again study an extension of I-27 from
Lubbock to Laredo.
State
highways
 |
The State
Highway system includes State Highways (SH), Loops (LP), and Spurs
(SP). There are also Park Roads and Business
Routes as well as a few "one-off" designations: OSR (Old San
Antonio Road) near Bryan, NASA Road 1 leading to the Johnson Space
Center, and Beltway 8 around Houston. |
"Loop"
A term you are sure to hear across the state is
"Loop". Even when they're Interstates, you'll usually hear beltways and
other
bypasses referred to as "Loop" such-and-such. For
example, I‑410 around San Antonio is usually called "Loop 410", and
I‑610 in
Houston is known simply as "The Loop" (usually with the cardinal
location
inserted, e.g. "the West Loop.") However, there is an
official
state highway designation of "Loop (LP)". This category
includes
many routes that are not even circular! Short
state
highways whose main purpose is to connect two or more highways are
usually designated as a Loop. A good example is Loop 1 (MoPac
Expressway) in Austin: it is basically straight and runs pretty
much through the heart of the city, but it connects several US, SH, and
FM routes along the way.
Business Routes
Prior
to 1991, all business routes
carried an internal or "hidden" arbitrary State Highway Spur or Loop
designation,
although in most cases they were actually marked with the business
route sign for the parent route from which they branched. In
1991, those internal designations were dropped and the business route
designations were made official.
How
Texas marks
business routes is unique. Firstly, TxDOT often (but not always) puts a
small
letter at the bottom of the
business route shields (see example to the
right.) This letter
indicates which branch in the series for the parent highway that
particular segment is. For example, US 90 passes through
several
towns. The business route through the first town would be
labeled
"A", the one through the next town labeled "B", and so on, with the
lettering starting at the western or northern end of the route. Letters
are often skipped to reserve them for possible future intermediate
additions.
Secondly,
on US business routes, TxDOT often does not use the
"BUS" or
"BUSINESS" plaque mounted above the US route marker. Rather,
the word "BUSINESS" is typically integrated within the US shield above
the
number, as shown to the right above.
 |
Interstate
Business Loops were fairly rare in Texas until the state decommissioned
all US highways that were completely coexistent with Interstates in
1991. Along those Interstates, the US route had previously
provided the parent route for the business routes. For example, where
I-35 and US 81 coexisted, the business route through towns along the
way were designed as Business US 81. Those have
since been replaced with Interstate Business Loops. |
|
|
Park roads
The
state also has 88 or so Park Roads and
Recreation Roads,
which provide access to state and national parks and other designated
recreational areas. TxDOT also maintains all roads within
state
parks, although most are not marked as state routes. |
 |  |
Farm-to-Market
roads
More
than half of the
state's highway system is comprised of the Farm-to-Market (FM) road
system, which also includes Ranch-to-Market (RM) roads. Although
the first FM road opened in in Rusk County in 1937, the system really
grew after the 1949
Legislature set aside $15 million annually (or about $200 million in
today's dollars) for their construction
to "help get farmers out of the mud." The system is generally
considered to be the largest secondary highway system in the
world. Its nearly 41,000 miles is more than double the
entire state highway mileage of the six New England states combined.
All FM roads are paved and most are two lanes.
The
semantic
idiosyncrasies of Texas roads continues with the FM system. Although
the
FM/RM route signs read "Farm Road" or "Ranch Road", the routes are
officially designated as "Farm-to-Market" or
"Ranch-to-Market". More head-scratching comes from the
fact that
larger green guide signs do mark the routes as "FM" and "RM" (see the
"signs" topic below.) There
is only one
route officially designated as "Ranch Road" (as opposed to
"Ranch-To-Market), that being Ranch Road 1
leading up to the LBJ Ranch east of Fredericksburg. There
are also three FM Spur routes and three Business FM routes. FM and RM
roads are numbered as a single system, i.e. there is not
an FM and RM road with the same number.
Old Farm-to-Market sign ca. 1959 (Source: TxDOT)
Out
of the 3,550 routes in the FM system, 3,370 are labeled as FM, leaving
just 180 routes designated as RM. The bulk of those are in a
large
cluster in the Hill Country and
Edwards Plateau area west of
Austin and northwest of San Antonio. There are also several RM roads in
West Texas
and the
Panhandle, and a few others widely scattered in the rest of the state.
The exact FM vs RM naming criteria is a mystery, but a couple of
theories have been proffered that include an assumption made
by
TxDOT on the type of activity one is likely to see along a particular
road (e.g. more cattle and horse trailers along RM roads and more farm
equipment like combines and tractors plying FM roads), or perhaps just
local preference.
With
the
explosive growth of metropolitan areas
in Texas over the years, many FM routes are now wholly or partially in
urban
areas. One could drive many of
these routes and never see a farm or ranch or even any agricultural
products
being
transported to market. Still, only about 4% of the total FM
mileage is within urban areas. Because of this incongruity, and to
ostensibly allow urban FM roads to take advantage of additional funding
sources reserved for metropolitan roadways, an effort was made in 1995
to
create a new classification
for FM routes in cities called "Urban Roads" to better discern these
roadways. The new routes would keep the same route number as
the previous FM or RM designation.
New
signage was also planned to accompany the change. The
proposed sign would have been the
simple
state highway square with the word "urban" and the route
number (see the example above left.) However, an unexpected uproar from
the public about changing the
apparently beloved Texas-shaped
sign-- not to mention the expense of doing so--
eventually stopped the
"un-Texan" plan to re-sign the roads. Instead, TxDOT's internal
highway designation logs were changed as planned to re-classify those
urban
segments as UR, but the existing FM and RM signs were left in place.
By
2018,
there were 251 roadway
segments classified as UR. However, the idea apparently never really
accomplished its stated objectives and was never fully implemented.
Instead, the inconsistent designations seemed to just cause confusion.
So in November of 2018, the Transportation Commission dissolved the
Urban Road designation and the routes were returned back to the FM
system.
Similar
to the
Urban Road system, TxDOT created a classification of roadway in 1988
called the Principle Arterial Street System, or PASS (designated as
"PA"
routes.) This classification allowed urban arterials that weren't state
highways, but that provided access to or relief for major
state corridors, to receive a special category of state
funding.
Due
to financial constraints, the PASS program was
essentially discontinued in 1992 and is slowly being sunsetted with the
190 roadway segments in the PASS system being funded as
resources become available or transitioned to other funding
categories. One of the shining examples of the PASS system is the
Wurzbach Parkway in San Antonio, which incidentally seems to be the
only PASS road signed as such.

Rare
"PA" route number signage
Innovation
Texas
has
always been on the leading edge of highway technology. The
Texas
Transportation Institute (TTI) at Texas A&M University has
spearheaded much of this highway research. Here are some of
the
many innovations to come from Texas:
- The
"Texas
Twist" guardrail end was developed in the 1970s to deflect vehicles by
burying the ends of the guardrails. As cars got smaller,
though,
many overturned when hitting this. So in the late '80s and
early
'90s, TTI developed a new guardrail end treatment called the
ET2000. This new guardrail end absorbs the impact of a
vehicle by
extruding the rail and breaking the wooden posts (you can see an
example of this in the photo above.)
- Texas
initiated the concept of roadside parks. The first such facility
opened in 1933 along Texas 71 between Smithville and La
Grange. In recent years, though, funding issues, as well as the
proliferation
of fast-food restaurants, has resulted in Texas closing an increasing
number of picnic and rest areas, especially near urban areas.
- The
"adopt-a-highway" project was developed in Texas, and it was the first
state to implement it statewide. All but one other states
have
since emulated this program. There are currently about 3,800
groups collecting litter along 8,000 miles of highway. It is
estimated that this program saves the state $3 million a year in
litter clean-up costs. (Also see the "Don't Mess With Texas"
section below.)
- Breakaway
sign
posts and streetlights were developed in a two-year program in the
1970s to reduce
the seriousness of roadside object impact accidents.
After
125 crashes resulted in not one single injury, the federal government
mandated their use on all federally-funded roads. Texas
also developed the breakaway "coat hanger" rural mailbox
support,
which was recently redesigned.
-
A modified
version of the standard Jersey-barrier designed to reduce the
likelihood of smaller vehicles flipping over on impact was developed in
the 1980s by TTI. TTI also designed a special heavy-duty,
extra-tall guardrail for a downtown San Antonio freeway ramp to prevent
heavy trucks from crashing down onto a high school football
field below. To test it, they crashed a fully-loaded
tanker truck into
it! This rail design has since been used in many other
locales
where extra strength crash-barriers are needed.
Don't
Mess With Texas ®
During
the mid
'80s, the forerunner of TxDOT introduced what would become an
incredibly popular anti-litter campaign: "Don't Mess With Texas".
Signs
went up around the state and the slogan took off. Today, you
can get "Don't Mess With
Texas" T-shirts, mugs, stickers, keychains,
hats... you get the idea. There have also been numerous
"Don't
Mess With Texas" commercials featuring various
celebrities. TxDOT owns
the trademark on the slogan and logo and zealously pursues
unauthorized uses.
ITS
With
freeways in
many areas reaching their maximum practical width, the Texas
Transportation
Commission in 1989 committed to building Intelligent Transportation
Systems (ITS) in the state's largest metro areas. The first
system to go online was TransGuide in San Antonio, which at the time
was the first advanced metro freeway ITS system in the
nation. TransStar in Houston followed shortly thereafter. All of the
state's metro areas now have ITS systems, and it has been
expanded to several busy rural corridors as well. These
systems
use a various technologies to monitor traffic conditions and warn
drivers of incidents and congestion. ITS also plays a major
role in hurricane evacuations and other emergency situations. As of
2017, the state's 14 traffic management centers operated 1,082
dynamic message signs and nearly 2,000 CCTV cameras.
Signs
Texas
has more
road signs than any other state. There are over 500,000 signs on state
maintained highways.
Texas
is probably
the only state that has two different versions of our highway
markers. One version is the freestanding sign and the other
is
for use on freeway guide signs. Here are some examples:
STANDALONE
SHIELDS |
|
GUIDE SIGN SHIELDS |
 |
|
 |
 |
|
 |
|
|
  |
After
World War II, the route marker for state highways was changed to
today's boring black and white square. Prior to then, the shield
featured the much more
unique circle and five-point star designs shown at the left. Based on
photos, the one on the far left seems to be the original route shield
used in the 1920s. Sometime in the 1930s, it appears to have been
changed to the one on the right. |
Toll
roads
Until the
early 2000s, Texas law prevented the state from
building or operating toll highways. Instead, they could be
built
and operated by subsidiaries of TxDOT or independent agencies created
specifically for that purpose. For instance, the Texas
Turnpike
Authority built and operated tollways in the Dallas area, including the
Dallas-Ft. Worth Turnpike, which was the state's first toll
road. North Texas tollways are now operated by North Texas Tollway
Authority
while the Harris County Toll Authority built and operates several
tollways in the Houston area (see sidebar below).
In
the late
'90s, a private toll road, the Camino Columbia, was built to connect
the Columbia Solidarity Bridge northwest of Laredo to I‑35. Due
to a lack of traffic caused by federal delays to implementing the
trucking rules of the North
American Free Trade Agreement (NAFTA), that road eventually was sold to
the state and is now operated by TxDOT.
In
the early 2000s,
with
worsening urban congestion and declining revenue from the static state
gas tax, the
state promoted toll roads as a major mechanism to fund new or
expanded roads. To facilitate this in areas without existing toll
authorities, the legislature
authorized the creation of so-called Regional Mobility Authorities
(RMAs). Perhaps the most controversial
toll road proposal was the statewide Trans-Texas Corridor project (see below).
Toll
roads in Texas are marked with special signage such as that shown to
the right above.
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The
Sam
Houston Tollway around Houston is also referred to as
Beltway 8. However, only the
frontage roads along most of the route are actually Beltway 8, which is a state highway. The
tolled mainlanes are just the "Sam Houston Tollway", which is operated by the
Harris County Toll Road Authority. While
it is officially titled "Beltway 8" and signed as such,
it is actually listed in the state's highway designation files as State
Loop 8. The "Beltway" designation was assigned as it had been named the
"Outer Belt" by Houston officials since its inception. |
Trans-Texas
Corridor
In 2002, Texas Governor
Rick Perry announced a concept for a massive new transportation system
in Texas. The plan, called the "Trans-Texas Corridor" (TTC),
was
subsequently approved by the legislature and called for 4,000 miles of
superhighway/rail/utility corridors crisscrossing the state. As
envisioned, each corridor would have been 1,200 feet wide and included
separate roadways for passenger vehicles and trucks, separate tracks
for freight and passenger rail, and a right-of-way for utilities such
as gas, oil, and water pipelines and electrical transmission and
telecommunications lines. Specifically, here's how a typical
corridor would have been divvied up:
- Four
truck
lanes, two each way (A on the diagram below)
- Six
passenger
vehicle lanes, three each way (B)
- Two
sets of
tracks for high-speed passenger rail, with stations (C)
- Two
sets of
tracks for freight rail (D)
- Two
sets of
tracks for commuter rail, with stations (E)
- A
utility
corridor about 200 feet wide (F)
- Maintenance,
safety, and expansion zones as necessary

Trans-Texas
Corridor typical cross-section
(Letters correspond to descriptions above)
The
roadways would have had limited interchanges with exits only at
intersections with other TTC routes, Interstates, US highways, and
major state
highways. It was planned that the passenger roadways would
have speed limits of 80 mph. The corridors would have been
developed and operated by private companies under a state
franchise. These companies would charge tolls and fees for
users.
There
were four priority corridors:
- TTC-35,
to
parallel or overlap I‑35 from Denison to Laredo
- TTC-69/future
I‑69, from Texarkana to Laredo via Houston, with branches to the Lower
Rio Grande Valley
- I‑45
from
Dallas to Houston
- I‑10
from El
Paso to Orange
The
project, however, met with fierce opposition across the state.
Opposition was especially pronounced in rural areas
as the wide corridors would have taken many acres of farming and ranch
lands. Furthermore, there was a general discontent with the
concept of having the roads operated by private companies, especially
ones with foreign ties. As a result, the project was killed
by
the Legislature in 2009. The TTC-35 and TTC-69 projects,
which
were in advanced planning at the time, continued but not under the TTC
brand. The TTC-35 project was also eventually canceled.
However, the segment from Georgetown to Seguin,
which had originally been conceived as a traditional toll project, was
allowed to be
completed as a regional project and today is SH 130. Planning
for TTC-69 (the I‑69
extension) continued as a traditional Interstate project (see I‑69
above.)

Map of
proposed Trans-Texas Corridor
(Priority routes are in
gold)
Speed limits
Texas
is the only
state that does not have statutory speed limits for different types of
highways in the state system. Instead, a general limit of 70
mph
applies on any rural numbered highway regardless of classification or
number of lanes and 60 mph on any other rural roadway. A 30
mph
general limit applies in urban areas. These limits can be
raised
or lowered on specific segments based on an engineering study. Speed
limits can be
raised to 75 mph on numbered highways and up to 85 mph on select
roadways. This means Texas is the only state that has 75 mph
speed limits on two-lane roads.
As
speed limits have been increased across most of the US in recent years,
Texas has lead the way. Today, Texas has an 80 mph speed
limit on
about 520 miles of I‑10 and I‑20 in west Texas. Several
tollways
in the Austin area also have an 80 mph speed limit, and SH 130 from SH
45 south of Austin to I‑10 near Seguin has an 85 mph speed limit-- the
highest in the United States.
Prior
to 2011, Texas posted separate speed limits for trucks and for
nighttime. The truck limits were usually 60 mph when the
general
speed limit was 65 mph or higher and 70 mph when the general speed
limit was 75 mph or higher. Nighttime speed limits were 65
mph
when the daytime limit was 70 mph or higher with nighttime
limits
for trucks generally 55 mph. All truck and nighttime speed
limits
were repealed in 2011.
To
help reduce air pollution, Texas experimented with so-called
"environmental speed limits" in the Houston and Dallas-Ft. Worth areas
starting in 2000. This scheme lowered the speed limit by 5
mph on
roads with an existing 65 or 70 mph limit. In 2002, speed
limits
in the Houston area were arbitrarily lowered to 55 mph regionwide, but
widespread opposition, poor compliance, and a finding that the lowered
limit did
not significantly improve air quality scuttled that plan within a
couple of years and speed limits returned to the original 5 mph
reduction scheme. However, the uproar caused
the state
legislature in 2003 to ban any new environmental speed
limits. Environmental speed limits in the DFW region were completely
repealed in 2015.
In
late 2014, TxDOT conducted a pilot project for variable speed limits at
three locations around the state. Variable speed limits are
those
that can be adjusted in real-time to address congestion, inclement
weather, construction, or other issues that could affect traffic
safety. The results of the pilot project showed that the concept was
beneficial. To date, though, no permanent implementations have been
planned.
Tunnels
& ferries
TxDOT
operates
two ferry services. The longest is on SH 87 from northern
Galveston to Port Bolivar. Another short ferry connects Port
Aransas and Aransas Pass on SH 361. Harris County
also
operates the Lynchburg Ferry east of Houston near San Jacinto State
Park. The Harris County Toll
Road
Authority studied a possible bridge to replace the Galveston-Bolivar
ferry, but determined it to not be feasible.
There
are
currently no tunnels on the state highway system. At one
time,
TxDOT did operate a tunnel under the Houston Ship Channel on SH 146
between La Porte and Baytown. It was replaced in the early
'90s
by the impressive cable-stayed Hartman Bridge. There are, however,
three road tunnels in Texas that are not part of the state highway
system: the Washburn Tunnel, which is also under the Houston Ship
Channel on Federal Road; the Addison Airport Toll Tunnel in Addison
north of Dallas (operated by NTTA); and one in Big Bend National Park.
Other
sites of interest
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