IH 35 NAFTA Trade Corridor: The future vision of IH 35 from Mexico to Canada

Charles A. Dodge
Vice President and Senior Project Manager
HNTB Corporation
San Antonio, Texas

Kent L. Ahrenholtz
Senior Transportation Planner
HNTB Corporation
San Antonio, Texas

The Federal Highway Administration (FHWA) and the Departments of Transportation in Texas, Oklahoma, Kansas, Missouri, Iowa and Minnesota combined their efforts to conduct a study of Interstate Highway 35 (IH 35) from Laredo, Texas to Duluth, Minnesota. The purpose of the study was to assess the need for improved local, intrastate, interstate, and international service on IH 35 and to clearly define a general feasible improvement plan to address those needs.

The IH 35 Corridor is illustrated in Figure S-1. Its multimodal transportation hubs—where air, rail, river, and truck cargo converge—make IH 35 ideally positioned to be a major route for what is expected to be increasing levels of international trade activity.

Since January 1, 1994, when NAFTA went into effect, the heartland of America has become an increasingly important thoroughfare for trade among the United States, Mexico and Canada. Interstate 35 is the only interstate highway connecting Mexico, the U.S. and Canada through the heartland, and it carries a greater percentage of U.S.-Mexico trade among the NAFTA partners than any other U.S. interstate highway.

This article highlights the analyses, findings and conclusions produced by the IH 35 Trade Corridor Study for improvements to the existing IH 35 Corridor. Included in the study was valuable information regarding the existing interstate condition, trade flow, trade analysis, cost, economic feasibility, impacts on economic development, financial viability, and other applicable data for this macro-scale study.

The study concluded with a recommended investment strategy for the IH 35 Corridor. The purpose of the study was to develop general strategies for the corridor and is intended only as a guide to future, potential improvements to IH 35. Decisions regarding specific solutions such as the addition of lanes or the provision of relief routes will be made based on engineering studies conducted by the various State Departments of Transportation in consultation with other affected parties. The strategy simply provides the participating states and FHWA with a planning tool to help guide decisions regarding future improvements to the IH 35 Corridor.

Study Process
Six states and the FHWA combined their efforts to conduct this study. The study was conducted through the nine tasks described below.

Existing Conditions and Planned Improvements: This first task was designed to gather, summarize and interpret existing data regarding the IH 35 Trade Corridor.

Public Involvement: The public involvement activities included public meetings and newsletters coinciding with major project milestones.

Current and Future Travel Demand: Travel demand models for forecasting freight and passenger vehicle flows were developed considering national and international trade with both Mexico and Canada. The demand models included consideration of current and future national and international trade and commodity flows. In addition, long-distance and local passenger flows were generalized and forecasted.

Evaluate Adequacy of Existing Facilities and Institutional Arrangements: Largely based on the travel demand, this task evaluated the adequacy of existing highway, rail, border crossing, and customs facilities in the IH 35 Trade Corridor.

Potential Corridor Strategies — Emerging Technologies: This task provided a vision of IH 35 to the year 2025. It identified emerging transportation and information technologies that may have applications in the corridor. Items investigated included:

  • Intelligent Transportation Systems (ITS) Applications
  • Freight Transportation Improvements
  • International Trade Services Centers
  • High Occupancy Vehicle Lanes
  • Super-Highways and Truck Ways
  • Fixed Guideway Passenger Rail Applications
  • Fiber Optics and Other Utilities
  • Commercial Vehicle Operations (CVO)/Seamless Travel
Potential Corridor Strategies — Innovative Financing: Financing strategies were investigated. Items investigated included:
  • Tollway Opportunities
  • Congestion Pricing
  • Modal Joint-Use In Corridor
  • Multi-State Infrastructure Banking
  • Public/Private Partnerships
  • Credit Enhancements
  • Privatization
  • Design-Build
  • Leasebacks
  • Build-Operate-Transfer
Identify Investment Strategy Options: This task identified a series of investment strategy options for the IH 35 Trade Corridor. These strategies were illustrated in the form of infrastructure improvement options for highways and rail as well as intermodal connections.

Evaluate Investment Strategies: Investment strategies were evaluated in this task. Benefits, costs, and impacts of each of the investment strategy options identified in the previous task were developed. Economic development benefits were estimated through the use of a REMI econometric model. Generalized cost estimates were used for each strategy and estimates of the impacts of environmental and socio-economic factors were made. A matrix comparison method was used to evaluate the different alternatives.

Recommended Corridor Investment Strategy: This task concluded with a recommended investment strategy for the IH 35 Trade Corridor.

Study Team
The IH 35 Trade Corridor Study Team was composed of representatives from each of the six participating states, the Federal Highway Administration, and a consultant team with experience in planning and design in each state. Assistance was also provided by the local Metropolitan Planning Organizations (MPO).

Representatives from the six participating states and FHWA were organized to form a Steering Committee. The committee was responsible for directing the consultant team, making key decisions for the study direction, reviewing the task reports, and conducting public meetings. The Texas Department of Transportation was the administrative agency for the study.

The consultant team included multiple firms with HNTB Corporation as the prime consultant for the study. HNTB is a multi-discipline architectural, engineering and planning firm that specializes in the transportation market. Wilbur Smith Associates (WSA), the principal subconsultant, is an international consulting, engineering, economics, and planning firm.

Alternative Investment Strategies Considered
A base case and five Candidate Alternatives were developed for the corridor. Each was assessed based on the best features of various scenarios, such as efficiency improvements to the IH 35 facility; increased use of railroads; expedited international freight processing; improved commercial vehicle operations; improved intermodal transfers; public transportation strategies; and a do little (base case) strategy.

The base case alternative is a Do Little Scenario. It includes maintenance of pavement and bridges; the implementation of committed improvements; other planned activities such as transit, demand management, ITS, and growth management. The five Candidate Alternatives were developed to meet the future year (2025) traffic projections.

The Base Case and five Candidate Alternatives were evaluated based on how they compared in achieving improvement objectives defined in the study. Based upon that evaluation, three alternatives that were considered the most viable, were selected for further study. These three alternatives are described below.

The viable alternatives have the following common features:

  • Assumes Base Case Improvements are included.

  • Maximum Upgrade (within existing right-of-way): Assumes that lanes are added to IH 35 to accommodate future public traffic volumes, to the maximum lateral capacity allowed by available right-of-way. However, since this component alone is not sufficient to meet the future year (2025) traffic projections, other improvements are included in all of the following viable alternatives.

  • Comprehensive ITS: Comprehensive ITS was recommended throughout the corridor with an emphasis on the urban areas.

  • Other Urban Considerations.
1. Relief Routes/Double Decking Strategy
This alternative adds to the Maximum Upgrade (within existing right-of-way) the following:

Relief Routes and/or Double Decking IH 35: In nearly every urban area segment, the future year (2025) traffic needs cannot be met by lane additions in the existing right-of-way. In this alternative, additional needs are met by providing additional lanes through some combination of urban area relief routes on new location, or elevated/depressed sections on existing IH 35.

Comprehensive ITS: The comprehensive ITS scenario is included in all urban areas.

Other Urban Area Considerations: Increased transit use, demand management, and growth management policies in urban areas are also included in this alternative.

2. Trade Focus Strategy
This alternative adds to the Maximum Upgrade (within existing right-of-way) the following:

Partial NAFTA Truckway (with Larger Truck Size and Weights): For this alternative, the truckway and larger truck size and weights are to be used only where their implementation could result in lane savings to IH 35. This is in the Southern portion of the corridor (between Dallas/Fort Worth, and Laredo, Texas) where the truck traffic demand projections are the highest. Two truckway options are possible—a separate facility and a truckway within the existing IH 35 right-of-way. This strategy assumes the truckway is located within the IH 35 right-of-way for environmental and cost purposes. This alternative also includes complete Intelligent Transportation Systems for commercial vehicle operators and pre-clearance centers for U.S., Canadian, and Mexican customs operations.

Relief Routes and/or Double Deck IH 35: In segments where lane deficiencies still exist, it is assumed that additional lanes are provided by this improvement strategy.

Comprehensive ITS: The comprehensive ITS scenario is included in the urban areas.

Other Urban Area Considerations: Increased transit use, demand management, and growth management policies in urban areas are also included in this alternative.

3. Combination Strategy
This alternative adds to the Maximum Upgrade (within existing right-of-way) the following:

Lane Addition with Right-of-Way Acquisition: Additional lanes are provided between Duluth and Kansas City by the acquisition of right-of-way in areas where such acquisition could eliminate the need for relief routes.

Relief Routes and/or Double Decking IH 35: The needs are met by this improvement strategy by providing additional lanes.

Rail Implementation (Kansas City to Laredo): Cooperative rail services are promoted between Kansas City and Laredo, to decrease freight traffic on IH 35.

Comprehensive ITS: The comprehensive ITS scenario is included in the urban areas.

NAFTA Scenario Improvements: This alternative does not include a truckway but does include all associated ITS and pre-clearance improvements included under the Trade Focus Strategy.

Other Urban Area Considerations: Public transit, demand management, and growth management policies are implemented in urban areas.

Recommended Investment Strategy Based upon a full analysis, the recommended strategy is the Trade Focus Strategy. This alternative has a number of important advantages over the other alternatives. These include providing good overall movement of traffic in the corridor as well as the best economic benefits of the alternatives studied. Additional advantages include:

  • Best reduction in travel times for traffic on IH 35;
  • Best reduction in accident costs;
  • Best benefit-to-cost relationships; and
  • Fewer environmental impacts.
The Trade Focus Strategy includes special provisions to accommodate truck traffic in that portion of the corridor with the highest percent truck volume. This occurs from the Dallas-Fort Worth area to Laredo.

The following are components of the Trade Focus Strategy.

1. Maintenance of Existing Facility. Over the next few decades, about 65 percent of IH 35 will require major upgrades; however, the entire route will have a continued need for rehabilitating pavements, resurfacing sections of the highway, and providing replacements of some bridge decks. Bridge substructures and superstructures will also need to be maintained, requiring repairs to maintain the integrity of the bridges.

Therefore, routine maintenance and repair efforts for the IH 35 Corridor are included in the Trade Focus Strategy. In addition, projects already committed for construction are included as well.

2. Intelligent Transportation Systems (ITS). The Trade Focus Strategy assumes implementation of a comprehensive ITS for commercial vehicle operations and pre-clearance technology throughout the corridor. An ITS program for the metropolitan areas is also included throughout the corridor. The type and scope of ITS services will be defined in detail in follow-up studies, and applications will vary.

3. Widening of IH 35. Analyses show that only about 35 percent of existing IH 35 corridor has a sufficient number of lanes to meet the needs in 2025. The remaining 65 percent will require substantial improvements to accommodate the anticipated traffic. The Trade Focus Strategy provides for the widening of 1,700 km (1,060 miles) of IH 35 commensurate with this anticipated demand. The number of lanes needed reflects the implementation of ITS and relief routes thereby reducing the total number of additional lanes needed to meet the demand.

4. Truckway Provisions. To accommodate truck traffic, the Trade Focus Strategy provides special features for trucks from the Dallas-Ft. Worth area south to Laredo. This involves about 785 km (490 miles). Options to consider include provisions for larger truck sizes and weights as well as the option of special lanes for trucks. The location for these lanes can be a separate facility near IH 35 or special truck lanes within the IH 35 right-of-way. The Trade Focus Strategy includes heavy duty pavement and bridges throughout the facility and inclusion of complete ITS for commercial vehicle operations. It also assumes the development of pre-clearance centers for U.S., Canadian, and Mexican customs operations.

5. Relief Routes. In a number of urban areas, relief routes are recommended because of the inability to meet the travel demand within the existing right-of-way constraints. Any capacity needs that could not be met within the right-of-way limitations, or other options discussed, it was assumed to be met by a separate relief route. As the specifics of any particular relief route are unknown, neither the benefits nor costs of these facilities were included in the analysis. The details of actual location and dimensions for specific relief routes of IH 35 require local studies.

6. Other Strategies. The Trade Focus Strategy includes incorporation of other transportation elements such as public transit services, travel demand management, and land use planning efforts such as growth management. Locations for new intermodal transfer facilities, U.S. customs operations, and improved linkages to existing facilities would be additional refinements. These refinements should be addressed in comprehensive planning studies for cities and counties, statewide transportation systems planning, and through comprehensive analyses of individual projects where major investments are required.

Analysis of the IH 35 Corridor showed that benefits accrued for all three viable alternatives that were further studied. However, the Trade Focus Strategy had the best return of all the alternatives as measures by annual cost savings, economic impact, and cost/benefit. The benefits were calculated in annual cost savings, economic impact and cost/benefit.

1. Annual Cost Savings. The following are the annual cost savings (in 1996 dollars) during the design year of the project year 2025, when compared with the base case alternative or the "do little scenario":

  • $1.15 billion annual vehicle operating cost savings;
  • $1.08 billion annual travel time cost savings; and
  • $151 million annual accident cost savings; that totals to
  • Almost $2.38 billion annual travel efficiency benefits by 2025.
2. Economic Impact. The economic impact during the construction and operational life of the project (calculated in 1996 dollars) for the primary impact area is projected to be:
  • $20.9 billion in discounted value added;
  • 43,100 permanent jobs created that can be attributed to the IH 35 Corridor improvements;
  • Over $30.8 billion in personal income added; and
  • Over $18.4 billion in added wages.
3. Cost/Benefit. The cost estimate for the Trade Focus Strategy using 1996 cost data is $10.9 billion. This includes costs for the following elements as described previously:
  • Roadway;
  • Structures;
  • Intelligent Transportation Systems (ITS); and
  • Engineering and administration.
When the total cost to implement the Trade Focus Strategy is compared to the benefits derived from it, the projection is that $1.86 in benefits will be realized for each dollar expended. The net present value for the strategy is projected to be $5.76 billion, which represents the net economic value of the project to the nation's economy.

Charles Dodge is a Vice President and Senior Project Manager with HNTB Corporation in their San Antonio, Texas Office. He lives three miles from IH 35 and travels the corridor almost daily in pursuit of his highway planning and design career, which is focused on the IH 35 corridor. He can be reached at 210-349-2277 or at

Kent Ahrenholtz is a Senior Transportation Planner in HNTB Corporation's San Antonio office. He has several years experience with corridor studies, including involvement in several coast-to-coast and border-to-border studies. He can be reached at 210-349-2277 or at