EXECUTIVE SUMMARY

INTRODUCTION

The City of Trinidad is approximately 22 miles north of Raton, New Mexico, and 37 miles south of Walsenburg, Colorado in Las Animas County, Colorado, as shown on Figure S-1. The project is located on Interstate 25 (I-25), in and adjacent to the City of Trinidad.  The study area begins at the Santa Fe Trail interchange and extends north to the Goddard Avenue (US 160 Bypass) interchange, as shown on Figure S-2. SH 12, the “Scenic Highway of Legends”, originates at I-25 in Trinidad and extends west and then north to Walsenburg.  US 160 follows I-25 south from Walsenburg and heads east at Trinidad.

The primary purposes of this project are to reconstruct an aging facility, provide a safe highway and accommodate future travel demands.  Construction of I-25 through Trinidad began in the early 1950's and was completed in the late 1960's.  Sections of the viaduct are now experiencing minor section loss, cracking and/or spalling. Highway design criteria have changed since the construction of I-25 through Trinidad, and the facility requires updated design practices in orderto improve the safety.  Some of the elements which need to be upgraded to current highway design practices include the mainline (both horizontal and vertical curvature), interchange, and ramp geometry.  Using current design practices, the freeway needs to be designed to accommodate not only existing traffic levels, but also future traffic demands.

EXISTING AND FUTURE CONDITIONS

The following six interchanges exist within this reach of I-25:

Five of the six existing diamond interchanges are diamond interchanges, but not all provide full movements.  Their geometry is influenced by the local street system and other constraints such as the BNSF Railroad and the Purgatoire River.  The geometry of the interchange at the University/Animas/S.H. 12 is strongly influenced by these features and as a consequence, the button-hook configuration is very substandard. 

An accident history evaluation was conducted for the I-25 corridor through Trinidad to identify specific locations with high occurrences of accidents.  The accident rate and severity on this segment of I-25 is slightly higher than average when compared to other segments of urban interstate highway statewide. There are two main areas of accident concentration.  The most significant area is at the Animas/University/S.H. 12 interchange, the other high accident area is at the Goddard Avenue Interchange.

An environmental overview has been prepared as a part of the project development process.  The EO focuses on archaeological and historical resources, vegetation, wetlands, wildlife, environmental justice and environmental contaminants.

Local growth is projected at a rate of approximately 2 percent per year over the next 20 years. Actual average annual growth rate for traffic on I-25 from 1993 to 1999 is in the range of five to seven percent. In order to forecast the year 2020 through traffic volumes on I-25, the existing traffic volumes on I-25 were increased at a rate of six percent per year, consistent with the past six-year traffic data.   Consequently, 2020 daily traffic volumes for I-25 are projected to be in the range of 51,000 vehicles per day.  Intersection operations for 2020 with no improvements are projected to be LOS F for several unsignalized intersections.  Three existing signalized intersections are projected to operate at LOS C or better during the AM and PM peak hours in the year 2020.

SYSTEMS EVALUATION

The project development process began in 1993 and has progressed over this time to reflect funding programs, community concerns and environmental investigations. Initially, a systems-level evaluation of eight alternatives was conducted to upgrade the replacement of deficient ramps and improve connections to the local street systems.  A series of evaluation criteria and corresponding weights were established to assess the eight alternatives.

A Preferred System alternative from this initial effort, formed the basis for the conceptual design which is determined to achieve the approved safety, spacing between the interchanges, moderate disruption to traffic, as well as a minimal impact to residences, businesses and the environment. Additionally, this initially Preferred System is considered to be a cost effective alternative. 

This system evaluation results in eliminating one interchange and relocating the Van Buren interchange to a future location at MP 12.

PROJECT LEVEL FEASIBILITY STUDY

Conceptual Design

Alternative 6 was used as the basis for developing the conceptual design.  Several options for Alternative 6 were presented at a public workshop on December 7, 1999.   The public favored inclusion of Options A and C, which included shifting the alignment for the viaduct portion to the east to provide a 65 MPH design speed for this portion of the viaduct and eliminate significant impacts to existing businesses on the west side of I-25 at Commercial Street.

Since then, the project team (FHU, CDOT, the City of Trinidad and FHWA) have analyzed the potential weave configuration between the Van Buren Street Interchange and the Main Street Interchange in further detail.  The team also developed a design alternative for the new connection of S.H. 12 with Main Street to avoid the historic Trinidad Tire Store.  The new section of SH 12 between Main Street and the existing SH 12 is recommended to have an access category of NRB (Non-Rural Arterial), which is consistent with the access category on the existing section of SH 12 west of I-25.   The section Main Street which will be designated as SH 12 (between I-25 and Santa Fe Trail) is recommended to have an access category of NRC in order to maintain existing accesses along Main Street.

FHWA expressed concerns the proposed improvements may not adequately address the substandard weave length.   Further, it was determined that the existing bridge overpass at Van Buren would have to be replaced due to inadequate vertical clearance and span lengths.  With these issues in mind, the project team identified a modified plan; relocate the existing interchange at Van Buren Street south to approximately M.P. 12.  This modification would provide the recommended one-mile spacing between the interchanges at Santa Fe Trail, M.P. 12 and Main Street.   These considerations were made part of the Preferred Alternative. This modification has received public support, as documented in a series of letters which are included in Appendix A.

As such, we identified two stages for implementation of the Preferred Alternative:

Interim Condition:		All improvements north of the existing interchange at Van Buren, with a temporary connection tothe existing facility immediately north. This would require removal of the existing north ramps at Van Buren.
Final Condition:		Construction of an interchange at Mile Post 12 and removal of the existing interchange at Van Buren.   This would require a new grade separation under I-25 for the Sopris Road connection to Van Buren.   The interchange at M.P. 12 would require extension of the west frontage road to provide access to the interchange.

Traffic Analysis

Year 2020 traffic volumes were modeled for both the Interim Condition and the Final Condition, and the Preferred System levels of service were compared with the “No-Build” levels of service.   The majority of the I-25 freeway segments between Van Buren and Goddard Avenue are projected to operate at LOS C during the PM peak hour.  The level of service in both directions of the freeway are expected to be LOS B or better outside this segment of I-25.  All projected year 2020 merge-diverge freeway movements for the Preferred System are expected to operate at LOS C or better.

The projected year 2020 AM and PM peak hour turning movement traffic volumes were used to determine projected year 2020 intersection operations as key locations for the Interim Condition and the Final Condition.  With traffic control improvements identified in this Study, all signalized intersections are projected to operate at LOS C or better during the AM and PM peak hours in the year 2020.

Replacing the Van Buren Interchange with the new interchange at M.P. 12 results in minor shifts in the traffic patterns, with slightly more traffic oriented to the Main Street Interchange.   The Main Street ramp terminal intersections and the intersection of Mains Street/Santa Fe Trail are projected to operate at acceptable levels of service.  Emergency vehicle response times will not be significantly affected by relocating the existing interchange from Van Buren to M.P. 12.

Phasing Plan/Funding Plan

Ten phases were conceptually identified to maintain traffic control during construction.  Phases 1 through 5 complete the project to the Interim Condition, Phases 6 through 10 complete the project to the Final Condition.   Some phases of construction will require temporary crossovers and two-way traffic operation on one of the two existing northbound and southbound highway sections.  Opinions of Probable Construction Cost are summarized as follows: