Rural Interstate Corridor Communications Study
Report to States
Appendix A

5.0 Constructability Considerations

The following section identifies the physical features and construction issues that may present barriers and opportunities to communications infrastructure deployment within the three study Corridors. Throughout each of the Corridors, these installation activities are subject to the same requirements as more conventional roadway construction activities. While somewhat commonplace in the roadway construction industry, they bear mentioning here as a reminder of the considerations that will present themselves for the construction of a fiber backbone along each of these Corridors.

5.1 I-20 Corridor

The I-20 Corridor through Louisiana, Mississippi, and Alabama is unique amongst the three being examined as part of this study, as it presents the most diversity in policies regarding the accommodation of communication utilities within Interstate highway right-of-way. In general, Louisiana has a liberal policy regarding utility accommodations, encouraging resource sharing for utilities to place communication infrastructure on Interstate highway right-of-way, including wireless towers. Mississippi and Alabama, however, have not engaged in shared resource projects, and current policies limit the ability of utilities to access Interstate highway right-of-way. The following sections provide a more detailed look at issues pertinent to the I-20 Corridor.

5.1.1 Geographic

The overall geography of the I-20 Corridor is flat or rolling terrain with occasional rock outcroppings, primarily in eastern Alabama. The land is heavily forested in rural areas and adjacent to the right-of-way. Wetlands are encountered frequently along the Corridor and the habitat supports a wide variety of plant and animal life. There are several urban centers along the Corridor including Shreveport, LA; Monroe, LA; Vicksburg, MS; Jackson, MS; Meridian, MS; and Birmingham, AL.

The I-20 Corridor contains numerous major water crossings which will present construction challenges. These major water crossings include:

Red River near Shreveport, Louisiana
Ouachita River in Monroe, Louisiana
Mississippi River at the Louisiana/Mississippi border
Black Warrior River near Tuscaloosa, Alabama
Cahaba River near Birmingham, Alabama
Logan Martin Lake near Lincoln, Alabama

In addition, the Cahaba River watershed is an environmentally sensitive area. The Cahaba River serves as the source of drinking water for over one million people and flows through heavily populated areas in the Birmingham metropolitan area. Construction in this sensitive habitat must adhere to the State's environmental policies, as is the case for all crossings of rivers and wetland areas in any of the I-20 Corridor States.

5.1.2 Bridge Attachments

The three States comprising the I-20 Corridor each have different requirements regarding conduit installations on bridge structures. The State of Louisiana requires rigid fiberglass "bullet-proof" conduit when mounting to bridge structures, but generally does not discourage bridge attachments as a method for crossing.

Where a freeway in Mississippi crosses a major valley or river on an existing structure, new utility installations will not be permitted at or after the time the highway route is improved, except for special cases as noted below. Where such structure attachments are requested, the utility owner must in each case show that:

The accommodation will not adversely affect the safety, design, construction, operation, maintenance or stability of the freeway;
The accommodation will not be constructed and/or serviced by direct access from the through-traffic roadways or connecting ramps;
The accommodation will not interfere with or impair the present use or future expansion of the freeway; and
Any alternative location would be contrary to the public interest. This determination would include an environmental evaluation of the direct and indirect environmental and economic effects covering on- and off-right of way alternatives.

Alabama has adopted a general policy of prohibiting utility attachments to structures except in extreme cases. Under normal conditions, where it is feasible and reasonable to locate utility lines elsewhere, attachments to highway structures will be avoided. Utility lines may be attached to a highway structure only when all of the following conditions exist:

No other practicable alternative is available, including private easement;
The attachment will not create a hazard to the public;
The public interest will suffer if approval is not granted;
The structural integrity of the facility will not be threatened by the attachment; and
The Department's basic interests will not be substantially compromised by the attachment.

For reasons of safety, ALDOT looks more favorably upon some types of utilities than upon others where attachments to structures are considered, and limits utility attachments to communications or water supply.

Corridor-wide construction will require consideration of the various water-crossing construction and permitting requirements.

5.1.3 Subsurface Considerations

The preliminary backbone alignment was designed using aerial mapping from Google Earth and a visual survey as noted in Section 2.1. Neither subsurface investigations nor geotechnical surveys were conducted as part of this study. General information regarding known surface conditions in the corridor is presented here.

All three States along this Corridor require that telecommunications conduit to be installed as close to the right-of-way line as possible, and each has similar conduit depth requirements, ranging from a minimum depth of 36 inches in Mississippi and Louisiana to 40 inches in Alabama. In addition, Louisiana employs a "first-come, first-served" utility installation policy. The first utility gaining a construction permit can install their infrastructure as close to the right-of-way line as possible. The next installer is forced to locate their facilities a set distance from the first. When the right-of-way is full, utilities must wait for an opportunity to install their infrastructure or lease infrastructure from an existing provider.

Louisiana also prefers not to have telecommunications infrastructure cross underneath railroad tracks due to the laborious and lengthy process of obtaining railroad permits, which can delay project construction, but they have allowed them in the past, as evidenced by existing communication utility placement along I-20.

The soils found throughout Mississippi are expansive Yazoo clay soils. Yazoo clay expands and contracts extensively. The underground conduit system must be capable of handling this expansion and contraction. The Appalachian foothills lie in eastern Alabama. This rocky region adds difficulty when constructing underground utilities. In the Calhoun area, east of Birmingham, soils are contaminated with PCB's. Construction in this area requires proper disposal of disturbed soil.

The New Madrid Seismic Zone (NMSZ) is a major seismic zone located in the mideastern United States. The effects of the fault zone reach into northeastern Louisiana, which includes the I-20 Corridor. Special structural design is required when constructing in the affected area.

5.1.4 Site Access

Various site access issues exist along the I-20 Corridor. These issues are both physical and regulatory and create site access constraints that require mitigation during construction activities. The most significant of these issues are discussed below.

Vegetation growth within the right-of-way could hinder access to the right-of-way. Vegetation includes mature trees with deep root systems and other undergrowth. Dense vegetation may require directional boring as the preferred method of installing underground conduit.

Where conduit will be mounted on bridges, appropriate construction techniques and equipment such as boats, cranes, and swing boom lifts will be required to gain access to the underside of the bridge deck and structures. This can present various safety-related issues that must be addressed by construction field crews. Where subsurface water-crossings are employed, access to the site could be constrained by natural features such as swift water currents or the presence of rapids.

Regulatory constraints include environmental considerations such as endangered species or water quality issues, and navigation concerns. All construction activity will require that the contractor conform to all State highway access requirements for Mississippi, Alabama, and Louisiana. These requirements include adherence to the Manual of Uniform Traffic Control Devices (MUTCD) traffic control requirements, National Electrical Safety Code, and U.S. Army Corps of Engineers (USACE) Wetlands Regulations, which contain wetlands permitting requirements.

5.1.5 Maintenance of Traffic

Safely maintaining traffic through the construction zone is the highest priority to all the States along the Corridor. To minimize disruption to traffic, the States all prefer to bore conduit under obstacles, especially if the alternative is mounting the conduit underneath a bridge structure. Where necessary, contractors will be required to prepare and seek approval for maintenance of traffic plans to ensure traffic flow safety during the construction period.

5.1.6 Safety

In general, the utility installing the infrastructure is responsible for the safety of the work site. Occupational Safety and Health Administration (OSHA) regulations must be followed at all times. Equipment that is not in active use must be stored in a safe location off of the right-of-way or near the right-of-way fence as far away from live traffic as possible. Construction vehicles must have safety and hazard warning lights active if they are located within the right-of-way work area. All workers must wear high visibility apparel per the requirements in the MUTCD. Hardhats and safety shoes should be worn where head and foot protection is warranted.

The integrity of the infrastructure is also a priority to all the States. All installations must conform to the respective State's specifications, codes, policies, and procedures.

All States require that conduit installed longitudinally along the facility be located as close to the right-of-way line as possible, again to minimize disruption to traffic during installation and maintenance, and to minimize accidental cuts due to State construction or maintenance activities within the right-of-way.

Geographical features can pose an increase in risk to workers and the environment. For example, I-20 crosses several major rivers, including the Mississippi River. Challenges associated with boring conduit underneath these large river systems or making bridge attachments pose an obvious risk to workers. When doing directional boring near river systems, the slurry runoff from the boring pit needs to be contained and not allowed to enter the waterway.

5.1.7 Coordination with Other Projects and Utilities

All utilities must have an approved permit to construct within or pass through State rights-of-way. All permits are reviewed by DOT personnel to determine if the proposed construction conflicts with other roadway or utility construction projects. Even if approved, the contractor must coordinate with the State and other utility providers to minimize conflicts. Each State has a "1-800-Dig" telephone number and requires the contractor to call and coordinate with other utilities in the area.

5.2 I-90 Corridor

The I-90 Corridor, incorporating parts of South Dakota, Minnesota, Iowa, and Wisconsin, presented the most uniformity in policies regarding shared resource construction activity. Each State physically located along the Corridor (Iowa is adjacent to the Corridor) openly encourages shared resource applications along I 90 as a method for obtaining access to high-speed telecommunications infrastructure for their States. All of the States have policies in place to accept applications to install communications along Interstate highway right-of-way and in the case of Minnesota and Wisconsin, to receive compensation in the form of cash or infrastructure. Communication utility access to I-90 in South Dakota is open, meaning that no compensation is sought for granting access to the Interstate highway right-of-way, but this only applies to fiber optic infrastructure. The following sections provide additional detail on constructability along the I-90 Corridor.

5.2.1 Geographic

The overall terrain on the I-90 Corridor is relatively flat and straight farmland. There are a few exceptions. There is mountainous terrain in the western part of South Dakota (Black Hills). In addition, the area approximately 10-20 miles east and west of the Mississippi River (Minnesota-Wisconsin border) is steep and has limited right-of-way due to rock cuts on either side of the Interstate highway. These hilly and mountainous areas make both wireline and wireless communication construction costly.

Urban centers located along the I-90 Corridor include Rapid City, SD; Sioux Falls, SD; Albert Lea, MN; Austin, MN; Madison, WI; and Janesville-Beloit, WI. In addition, Worthington, MN, Rochester, MN, and La Crosse, WI are near by.

The I-90 Corridor crosses several rivers and streams. Most are small and will not require expensive construction techniques or material to install fiber conduit. The major water crossings include:

Mississippi River at the Minnesota-Wisconsin border
Lake Francis Case near Chamberlain, South Dakota

These crossings will require relatively costly construction methods such as directional boring or reinforced conduit attached to bridges. In general, all of the Corridor States allow bridge attachments. Minnesota requires the utility to perform structural calculations and provide documentation to the DOT that shows no adverse effects from the attachment. Wisconsin only states that the attachment must not affect the structural integrity or appearance of the bridge and must not interfere with operations or maintenance. South Dakota allows attachments when other methods can be shown to be too costly or impractical.

In locations where the land is very flat, drainage can be a concern. Many landowners adjacent to the freeway belong to specific drainage districts, and if drainage patterns were to change it could affect a farmland's productivity. Particular consideration should be given to this issue during the design and construction process. The flat land can also be problematic for maintenance issues during winter when blowing and drifting snow can occasionally cause road closures.

States along this Corridor generally require that telecommunications conduit be installed as close to the right-of-way line as possible and each has conduit depth requirements ranging from 24 inches in Wisconsin to 36 inches in Minnesota. In South Dakota, the depth of installation is 48" in rural areas and 36" in other areas.

5.2.2 Subsurface Considerations

The preliminary backbone alignment was designed using aerial mapping from Google Earth and a visual survey as noted in Section 2.1. There were neither subsurface investigations nor geotechnical surveys conducted as part of this study. General information regarding known surface conditions in the corridor is presented here.

Subsurface rock is a concern for the entire Corridor. Rock is expensive to trench through and will add significant costs to a telecommunications installation. For a large part of the Corridor, the rights-of-way present relatively easy construction through loam type soils with glacial till encountered. However, significant subsurface rock will likely be encountered and will require mitigation.

5.2.3 Site Access

Various site access issues exist along the I-90 Corridor. These issues are both physical and regulatory and create site access constraints that require mitigation during construction activities. The most significant of these issues are discussed below.

Vegetation growth within the right-of-way could hinder easy access to the right-of-way. Vegetation includes mature trees with deep root systems and other undergrowth. The I-90 Corridor has little problematic vegetation throughout South Dakota and Minnesota, and forested areas are primarily encountered in eastern Minnesota and in Wisconsin.

All of the I-90 Corridor States require that, where practical, access to the construction site should be gained from a nearby public street or private property and not the freeway or freeway ramps. Fence removal or use of fence gates to access the site is at the discretion of the permitting agency.

5.2.4 Maintenance of Traffic

A traffic control plan should be submitted with each utility permit application. Each State in the I-90 Corridor requires that the traffic control plan conform to the MUTCD. Work must not begin on a site until all the traffic control devices are in place. Work in urban areas must be performed during off peak traffic hours, which are generally 9am to 3pm, and 10pm to 6am.

5.2.5 Safety

In general, the utility installing the infrastructure is responsible for the safety of the work site. OSHA regulations must be followed at all times. Equipment that is not in active use must be stored in a safe location off of the right-of-way or near the right-of-way fence as far away from live traffic as possible. Construction vehicles must have safety and hazard warning lights active if they are located within the right-of-way work area. All workers must wear high visibility apparel per the requirements in the MUTCD. Hardhats and safety shoes should be worn where head and foot protection is warranted.

5.2.6 Coordination with Other Projects and Utilities

Work within the highway right-of-way should be coordinated to minimize disturbances to any other contractor working in the right-of-way. It is the responsibility of the utility to coordinate work with other contractors. Traffic control plans should be coordinated to minimize the disruption to traffic.

5.3 I-91 Corridor

The I-91 Corridor comprises portions of Massachusetts, Vermont, and New Hampshire (I-91 is located adjacent to New Hampshire). This Corridor is unique in that it is the most advanced in terms of progress toward developing a shared resource project along the Corridor of the three Corridors studied. Massachusetts has selected a design/build team to install communications infrastructure and Vermont is developing a shared resource project for contracting in the near future. The following sections provide a more detailed look at this and other issues pertinent to these States.

5.3.1 Geographic

The I-91 Corridor generally parallels the path of the Connecticut River through Massachusetts and Vermont. Urban areas along the Corridor include Springfield, MA; Holyoke, MA; Northampton, MA; and Hanover, VT. Along this path, the roadway crosses several rivers and streams. Most are small and will not require expensive construction techniques or material to install fiber conduit. The one major river crossing is the Connecticut River near Springfield, Massachusetts. This major crossing will require relatively costly construction methods such as directional boring or reinforced conduit.

Attachments to structures in Massachusetts are to be avoided in accordance with the State's utility accommodation policy, but are allowed by permit when other methods are impractical and the attachment does not adversely affect operations, maintenance, or safety.

The terrain varies along the 242 miles of the Corridor. Through the Massachusetts portion, the roadway traverses the relatively flat land of the Connecticut River Valley. As the roadway winds its way northward through Vermont, the terrain becomes steadily more rugged up to and through the Green Mountains. In locations where the land is very flat, drainage can be a concern.

States along this Corridor generally require that telecommunications conduit to be installed as close to the right-of-way line as possible, but in an upcoming project to install fiber optic infrastructure, Vermont is requiring installation along the shoulder due to ROW restrictions and to avoid rock outcroppings. Massachusetts and Vermont have similar depth requirements for conduit installations.

There were neither subsurface investigations nor geotechnical surveys conducted as part of this study. General information regarding known surface conditions include subsurface rock being a concern for the entire Corridor. Rock outcroppings can be expected along the Corridor. In addition, subsurface rock should be expected throughout the Connecticut River valley. Rock is expensive to trench through and will add significant costs to a telecommunications installation.

Massachusetts, Vermont, and New Hampshire are located in an active seismic zone with historically low earthquake activity. However, reasonable steps should be taken to minimize potential seismic damage to vital communications facilities.

5.3.2 Site Access

Various site access issues exist along the I-91 Corridor. These issues are both physical and regulatory and create site access constraints that require mitigation during construction activities. The most significant of these issues are discussed below.

Vegetation growth within the right-of-way could hinder easy access to the right-of-way. Vegetation includes mature trees with deep root systems and other undergrowth. Dense vegetation may require directional boring as the preferred method of installing underground conduit. Forested areas exist along the entire length of the I-91 Corridor and are adjacent to the right-of-way.

Any construction activity will require that the contractor conform to all State highway access requirements for both MassHighway and the Vermont Agency of Transportation. These requirements include:

Commonwealth of Massachusetts - Regulation 720 Section 13 – Approval of Access to State Highways
Vermont Agency of Transportation Regulation - "Work Within Highway Rights-of-Way"

5.3.3 Maintenance of Traffic

A traffic control plan should be submitted with each utility permit application. Each State in the I-91 Corridor requires that the traffic control plan conform to the MUTCD. Work must not begin on a site until all the traffic control devices are in place. Some work may be required to be performed during off peak traffic hours to minimize traffic impacts.

5.3.4 Safety

In general, the utility installing the infrastructure is responsible for the safety of the work site. OSHA regulations must be followed at all times. Equipment that is not in active use must be stored in a safe location off of the right-of-way or near the right-of-way fence as far away from traffic as possible. Construction vehicles must have safety and hazard warning lights active if they are located within the right-of-way work area. All workers must wear high visibility apparel per the requirements in the MUTCD. Hardhats and safety shoes should be worn where head and foot protection is warranted.

5.3.5 Coordination with Other Projects and Utilities

5.3.6 Environmental Mitigation

As with any construction project, various environmental concerns will have an impact on the constructability of a fiber optic conduit trench or tower. These concerns include wetlands, endangered species and habitats, and materials disposal. While these concerns are true of any location in the US, they are of particular concern in Massachusetts and Vermont with their histories of environmental activism and legislation. Contractors will need to conform to all State and federal permitting regulations and develop mitigation strategies where required.

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Rural Interstate Corridor Communications Study Report to States Appendix A