This is the official Texas Department of Transportation Trans-Texas Corridor Plan, adopted June 2002

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Trans Texas Corridor Plan
Looking Down the Road - Executive Summary - Action Plan - Planning - Design > Environmental - Right of Way - Toll - Rail - Dedicated Utility Zone - Finance



Safety, improved travel time and reliability will characterize the Trans Texas Corridor. Planned for phased construction, it will connect cities across the state with a series of multimodal corridors featuring:

  • A high-speed, controlled-access tollway with separate lanes for passenger vehicles (three lanes in each direction) and trucks (two lanes in each direction).

  • Two-way rail (six tracks, three in each direction) with separate commuter/freight and high-speed passenger facilities.

  • A dedicated utility zone for transmission of oil, natural gas, energy, water and data.

Separating passenger vehicle and truck lanes to benefit the traveling public is fundamental to the corridor’s overall design. To avoid contributing to urban congestion, the corridor will have connectivity to major cities while not flowing directly through them. The corridor also will be designed to take advantage of intelligent transportation systems.

The vision is that the corridor will be developed in phases through several scenarios. For example, the two truck lanes (each direction) would be built first, to be shared initially by both passenger vehicles and trucks. As traffic volumes increased and additional capacity is warranted, separate passenger lanes would be constructed. This can be accomplished without disrupting the existing roadway.

The rail component also lends itself to phased construction. To make this a more feasible element for the corridor, a single track for freight/commuter line would be constructed initially. Freight and/or commuter rail lines would be built first along segments most needed to relieve pressing transportation problems. Construction of high-speed passenger rail to connect the largest population areas would be implemented as the need for alternative travel modes grows.

The 200-foot-wide utility zone will accommodate large water lines, natural gas and petroleum pipelines, telecommunication fiber-optic cables and high-power electric lines. Because of rapidly changing technologies, utilities will not be installed until needs are clearly identified. The utility zone initially would be leased for agricultural purposes where feasible. Conduit for data transmission would be installed initially and be ready for use. Hydrocarbon products, energy, and water would be constructed as demand for these products occurred.

In addition to design recommendations, this section provides cost analyses for the following features:

  • Separate lanes for passenger vehicles and trucks.

  • High operational speeds.

  • Bridge structures.

  • Interchanges.

  • Special vertical and horizontal grades.

  • Special rail features.

  • Dedicated utility zone.

Although the design and cost analyses reflect construction of all corridor components, individual elements can be phased in as needed. All corridor cost estimates shown in this report are based on current values.

Design elements

Separate passenger vehicle and truck lanes

In the ultimate design, passenger vehicle and heavy truck traffic will be separated for reasons of safety, economy and user appeal:

  • Safety. At high speeds, separating the two types of vehicles is safer because they have differing operational characteristics. At high speeds, these become even more pronounced. Lane separation also will increase visibility.

  • Economy. Heavy trucks require thicker pavement, which is more expensive. With the two modes separated, only the truck lanes must have significant load-carrying capacity. The separation also enhances operational efficiency and toll viability.

  • User appeal. Passenger vehicles will not have to slow for trucks climbing grades. Separate passenger and truck lanes will reduce stress and fatigue for drivers of both types of vehicles.

The separation is essential to achieving greater speed, efficiency and safety along the corridor.

High operational speeds

The corridor will be designed for the following operational speeds between connections:

  • 200 mph for high-speed passenger rail.

  • 80 mph for commuter/freight rail.

  • 80 mph for tollways (the speed limit will be determined by the Texas Transportation Commission prior to the opening of corridor segments).

Bridge structures

All roadways (excluding unpaved county roads), rails and streams intersecting the corridor are assumed to be grade-separated.

Most crossings will be handled by simple grade-separation bridge structures. These allow existing local highway and rail facilities to cross the corridor but not access it. Grade separations will be provided for farm to market highways, two-lane state highways, rail lines and paved county roads.

The corridor may cut through about 1,200 unpaved county roads. These roads will be reconnected to other facilities to maintain efficient traffic flow. TxDOT will endeavor to assist counties in rebuilding any important intra-county routes affected by the corridor.


Interchanges will allow for planned development and connectivity, making the corridor an efficient ground transportation system. Two basic interchange designs will be used: double-diamond and direct-connection.

Double-diamond interchanges will be used where the corridor intersects a highway serving a significant regional traffic base. These interchanges will provide access to and from the corridor and the crossing facility. Double-diamond interchanges will be necessary for about 60 percent of all state highways and 80 percent of all U.S. highways intersecting the corridor.

Directional interchanges will be used where a corridor segment intersects a major highway serving cross-state traffic. Much of the traffic from both the corridor and crossed highway facilities will need an interchange between these intersecting routes. Direct-connection interchanges will be provided at all 23 locations where the corridor intersects itself, at all interstate highways intersecting the corridor and at about 20 percent of the U.S. highways.

Horizontal alignments

For roadways, the horizontal curvature within the corridor section will have minimum radii to support the applicable vehicular speed.

Special rail features

All rail lines will be two-way, allowing use in either direction as needed. Because high-speed passenger rail is not compatible with conventional freight rail and commuter rail, the two features will be separated within the corridors.

High-speed passenger rail will not exit the corridor. Depots will be provided within the corridor for loading and unloading long-distance passengers.

Although commuter rail may exit the corridor when feasible, passenger stations will be provided in the corridor for short- and long-distance arrivals and departures.

Dedicated utility zone

The dedicated, separate utility zone is an important part of the corridor concept. This portion of the corridor may initially remain undeveloped, reserved for future need.

Typically, corridor right of way will vary in width up to 1,200 feet to accommodate the vehicular lanes, rail and utility components. Interchanges and areas of unusual terrain will require additional right of way.

Corridor width is based on specific features developed for a typical section. It allows for separation of truck and passenger vehicle lanes with safety zones sufficient to accommodate future roadway expansion. The first phase of corridor structures will allow for this expansion without reconstruction of the individual elements. An operational maintenance zone will separate the commuter/freight rail from the high-speed passenger rail component. The 200-foot wide utility zone will be sufficiently wide to accommodate both underground and above ground transmission components.

Table 1. Corridor composition

Feature Description

Truck lanes: Running in each direction, two 13-foot lanes, 12-foot outside shoulder, and a 4-foot inside shoulder.

Passenger vehicle lanes: Running in each direction, three 12-foot lanes and two 10-foot shoulders.


The railroad lines will be positioned between the truck lanes and the utility area, outside the highway median, for the following reasons:

  • To provide better access to the rail corridor for regular maintenance and emergency operations.

  • To support more efficient interchange design.

  • To make the design more environmentally attractive, with the utility area buffering rail noise for adjacent property owners.

High-speed passenger rail: Two separate tracks will be provided.

Commuter/freight rail: Four tracks will be provided, two dedicated to commuter rail and two for freight rail. All four tracks can be used by commuter or freight for entering and exiting the corridor, for maintenance, for emergencies or other needs.


The utility zone is designed to accommodate water lines, natural gas and petroleum pipelines, telecommunication fiber-optic cables and high-power electric lines. The electric lines will probably be overhead lines because of the high cost of burying high voltage lines. Right of way widths will vary from 50 to 175 feet for different voltage electric lines to increase minimum widths. Except for electric lines, right of way may be shared among the other utilities. Lift stations needed for water lines (5 acres) every 70 to 100 miles and for oil and gas lines (200 by 200 feet) every 100 to 200 miles will need to be accommodated. For more efficient access, all utilities should be situated in the 200-foot strip outside the commuter and freight railroad area. For maintenance, utilities will be accessed from roadways outside the corridor.

Estimated corridor costs are based on a typical section and the projected number of interchanges and grade-separation bridge structures. The typical section may vary from one segment to the next and may result in a different cost per mile than shown in this report. Historical unit bid data for the following corridor features were used:

  • Pavement (truck and passenger vehicle lanes).

  • Grade-separated bridge structures.

  • Interchanges.

  • Commuter and freight rail.

  • High-speed passenger rail.

  • Utilities.

Other items, such as engineering and contingencies, signing, striping, landscaping and drainage, are considered as a percentage of the total cost and are included in these estimates.

Cost estimates


Cost estimates for pavement distinguish between pavement for truck traffic and passenger vehicle traffic. Both truck and passenger vehicle roadways should have sufficient structural capacity so that only occasional maintenance overlays to restore ride quality, cross slope, surface friction and texture will be required over the design life. Cost per centerline mile is based on the various widths of each pavement layer.

Truck lanes

The 42-foot-wide truck roadway sections will include:

  • 4-foot inside shoulders.

  • Two 13-foot travel lanes.

  • 12-foot outside shoulders.

Pavement cost for a four-lane truck roadway is estimated at $3,105,000 per centerline mile.

Passenger lanes

The 56-foot-wide passenger vehicle roadway sections will include:

  • 10-foot inside shoulders.

  • Three 12-foot travel lanes.

  • 10-foot outside shoulders.

Pavement cost for a six-lane passenger vehicle roadway is estimated at $1,093,000 per centerline mile.

In addition to increased safety and other operational benefits derived from separating passenger vehicles and heavy truck traffic, the design allows significant savings in pavement costs. This is because lanes designed for mixed truck and passenger vehicle traffic would require thicker pavement. With separate roadways for trucks and passenger vehicles, only the truck lanes need the thicker pavement.

Other roadway costs in addition to pavement structures will include mobilization, clearing right of way, excavation, embankment, drainage structures, landscaping, signing and pavement markings, and safety features. These are estimated at $2,799,000 per centerline mile. Total roadway cost per centerline mile is estimated at $6,997,000.

Grade-separated bridge structures

Bridge structure costs include all structures that carry other facilities over the entire corridor or carry the corridor over water. Table 2 shows the cost estimates for grade-separation bridge structures.

These reflect current average statewide costs for new construction and do not account for specific terrain.

Table 2. Estimated costs for grade-separation bridge structures

Type of facility Number


Total cost


106 $11,200,000 $1,187,200,000
Farm to market 471 $3,480,750 $1,639,433,250
State/US hwy. (2-lane) 55 $4,709,250 $259,008,750
Paved county road 697 $2,661,750 $1,855,239,750


41 $68,970,000 $2,827,770,000
Stream 371 $34,485,000 $12,793,935,000
Small creek 2,000 $1,301,250 $2,602,500,000


3,741   $23,165,086,750

The average cost of grade-separated bridge structures is estimated at $5,175,000 per centerline mile.


Estimates shown in Table 3 for interchanges reflect current average statewide costs for new construction and do not account for specific terrain.

Table 3. Estimated costs for interchanges

Type of facility Number Cost Total cost
Double-diamond 160 $10,143,000 $1,622,880,000
Major hwy. fully directional 46 $202,125,000 $9,297,750,000
Corridor "Y" 16 $79,233,000 $1,267,728,000
Corridor fully directional 7 $301,987,000 $2,113,909,000
Total 229   $14,302,267,000

The average cost of interchanges is estimated at $3,195,000 per centerline mile.

Commuter and freight rail

The corridor is planned to include four conventional commuter and freight rail tracks. Two tracks will be dedicated for commuter rail and two for freight. However, all four tracks can be used by commuter or freight trains to enter or exit the corridor for maintenance, emergencies, or other needs. Commuter and freight tracks will cost the same. Cost estimates for commuter and freight rail are based on the following additional assumptions:

  • Double crossovers every 10 miles between each freight/commuter rail pair (crossovers require larger turnouts).

  • Two setout tracks at each double crossover required to support train maintenance.

  • Train-control signals with a central traffic control system.

Table 4. Estimated costs for commuter and freight rail

Item Cost/mile/track Total cost/mile (for 4 tracks)
Embankment $100,000 $400,000
Subgrade $175,000 $700,000
Ballast, ties, rail, labor $590,000 $2,360,000
Double crossovers $45,000 $180,000
Single crossovers between commuter rail and passenger stations plus miscellaneous items $2,500 $10,000
Setout tracks $25,000 $100,000
Upgrade to heavier rail $30,000 $120,000
Train control signals $136,000 $544,000
Total   $4,414,000

The use of freight cars capable of accommodating heavier loads allows for transportation of increased tonnage in a single train. The corridor will have heavier rail for these freight cars. The average cost for conventional commuter/freight rail is estimated at $4,414,000 per centerline mile for four tracks. This estimate does not include passenger stations or dispatch control centers.  Including costs for mobilization, excavation and embankments as well as incidental expenses associated with construction of new track, the cost is estimated to be $7,357,000 per centerline mile for four tracks.

Of all the corridor components, rail best lends itself to phased construction.  One track would serve both directions initially. This would significantly reduce initial capital outlay.

High-speed passenger rail

The estimated cost per centerline mile is $3 million for two tracks.  Including additional construction costs, the total estimated cost of this component would be $5 million per centerline mile.

Right of way

Right of way costs are based on the assumption that the corridor will be a new controlled-access facility on a new location, with no existing access. The estimate also is based on the assumption that no major land acquisition in metropolitan areas would be required. Costs include relocation assistance. One hundred percent of any existing utility adjustments should be eligible for state cost participation, and those numbers are included in the total cost for right of way. Upgrade of existing utilities is not included in the cost.

The up to 1,200-foot corridor will require 146 acres of right of way per mile. The total anticipated right of way for 4,000 miles of corridor is 584,000 acres. At a cost range of $20,000-$65,000 an acre for acquisition, right of way costs are estimated to be from $11.7 to $38 billion.


Each corridor will include a 200-foot-wide dedicated utility zone. Because of rapidly changing technologies, utilities may not be installed until needs are clearly identified. Initially, the state would lease undeveloped segments of the utility zone back to adjacent landowners. Anticipated costs per mile to construct this portion of the corridor will vary due to terrain and other geological conditions.

Estimated utility zone infrastructure costs are:

  • $350,000 per centerline mile for overhead electric transmission lines.

  • $800,000 per centerline mile for petroleum pipelines.

  • $2.5 million per centerline mile for water lines up to 60 inches.


Toll booths and plazas, rail passenger stations, dispatch control centers and maintenance sites also will be required. In addition, new types of vehicles under development or contemplated will require new communications facilities along the corridor.

Also, since the corridor will be all-new construction, environmental mitigation costs may be substantial.

Accommodating new technology and providing environmental mitigation will require about $2 million-$5 million per centerline mile.

Total estimated costs

Table 5 shows total average cost estimates for the corridor per centerline mile, excluding right of way and other subordinate costs.

Table 5. Corridor estimated costs/centerline mile

Item Cost/centerline mile
Roadway: Trucks/passenger vehicles $6,997,000
Grade-separation bridge structures $5,175,000
Interchanges $3,195,000
Commuter and freight rail $7,357,000
High-speed passenger rail $5,000,000
Utilities $3,650,000
Total $31,374,000

Note: Right of way and miscellaneous costs not included.

Based on an estimated cost of $31.4 million per centerline mile, the 4,000-mile corridor would cost $125.5 billion, not including right of way and miscellaneous costs. Factoring in right of way at $11.7 to $38 billion and miscellaneous costs at $8 billion to $20 billion, total estimated corridor cost would range from $145.2 billion to $183.5 billion.

Looking Down the Road - Executive Summary - Action Plan
Planning - Design > Environmental - Right of Way - Toll - Rail - Dedicated Utility Zone - Finance


This Page Last Updated: Sunday December 31, 2006
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