13. COST CONSIDERATIONS

Because of the vast number of diverse factors which affect the cost of manufacturing, transporting, and erecting noise barriers and their components, no attempt is made in this Handbook to provide specific costs for a particular noise barriers type. However, numerous sources exist which can assist a designer and/or decision-maker in evaluating the cost implications of different barrier types. Two primary sources suggested for initial contact are:

• State and Provincial contacts included in Section 16.5 of this Handbook. These individuals have access to information or sources related to noise barriers constructed in their jurisdiction.
• The Summary of Noise Barriers Constructed document^ref.37 published on a regular basis by the U.S. Department of transportation, Federal Highway Administration, Office of Natural Environment. This document gives details related to barrier type, dimensions, location, cost, etc. constructed in each State.

These initial contacts are likely to provide additional cost-related information sources and contacts such as:

• Specific reports prepared by States or Provinces related to barrier costs;
• Specific project-related information;
• Contractor contacts;
• Supplier contacts; and
• Manufacturer contacts.

The remainder of this section describes additional cost considerations.

13.1 Relationship of Barrier to Project Type

13.1.1 Noise Barrier Built as a Component of Large Construction Project.
The cost of noise barrier construction is usually less if the barrier is built as part of a large construction project. Costs for items, such as mobilization, insurance, maintenance, protection of traffic, etc., are spread out amongst all project elements. The equipment and manpower required for noise barrier erection may already be required for construction of other project elements. In general, such economy of scale factors are present on these large projects.

13.1.2 Sole Noise Barrier Construction Project / Retrofit Noise Barrier Construction.
When noise barrier construction is the sole or primary element of the construction project, then the costs of items, such as mobilization, insurance, and maintenance of traffic are attributable solely to the barrier construction. This situation, typically associated with a Type II or retrofit barrier construction, adds costs to the barrier construction, as compared to the cost of a similar barrier when part of a larger construction project. These additional costs can double the cost of the barrier installation. The equipment, materials, and manpower associated with such construction is required for only one task (noise barrier construction and its associated traffic control), with little opportunity for economy of scale applications.

13.2 Physical Conditions and Factors

13.2.1 Accessability.
The ability to reach the noise barrier location will also influence the overall barrier cost. Barriers on top of large cut sections may require large cranes to lift barrier components (panels, posts, reinforcement, etc.) and construction equipment (drills, form work, etc.) to the site. In addition, concrete may need to be pumped to the site or even mixed on the site with materials lifted by crane. Barriers constructed in limited space areas (such as on structures, near traffic, etc.) will typically cost more to construct than barriers constructed in areas where freedom of movement is not restricted.

13.2.2 Transportation of Material, Equipment, and Work Force.
In addition to the accessibility issues discussed above, the location of the barrier system components (earth, fabricated elements, etc.), the equipment (cranes, drills, form work, etc.) needed to erect the barrier, and the manpower to install the barrier are also factors influencing barrier cost. If barrier materials must be shipped from far-away distances, costs will be greater than for locally obtained material. In addition, if specialized expertise is needed for a particular barrier installation, the required manpowers' proximity to the project will be a factor influencing cost.

13.2.3 Quantity of Barrier.
The unit cost of a small quantity of a noise barrier will likely be greater than the unit cost for larger quantities of a barrier. The same or similar degree of insurance, mobilization, equipment type, and maintenance of traffic may be required to build 150 m (492 ft) of barrier as would be needed for 1500 m (4920 ft) of barrier. Form work, form liners, and similar fabrication layout is required if 50 or 500 noise panels are manufactured. Coating of a full roll of steel may be necessary, even if the full roll is not required for the particular project. Any specialized erection equipment or jigs will be required whether 10 or 100 barrier segments are erected.

13.2.4 Material Availability.
Readily available materials will reduce barrier costs. If materials must be specially ordered, or if long manufacturing lead time is required, construction schedules can be affected, adding costs to the barrier construction. Any changes required by field adjustments, broken panels, etc., will be less costly if the material is readily available.

Further, since replacement of barrier elements may be required throughout the life of the noise barrier, the availability of replacement parts becomes a critical issue. To address this concern, some agencies have instituted a stock piling policy where the contractor/ manufacturer, at the time of construction, supplies additional components to the organization responsible for maintenance. Typically, an additional 10 percent would by supplied to the responsible organization for stock piling purposes. The disadvantage to this type of practice is that the responsible organization, after several years of constructing noise barriers, may end up with an excessively large amount of varying stock on hand that has the potential of never being used. The issue of future availability becomes even more critical when the components have to be custom fitted with either very few or none of the pieces the same. In this situation, stock piling may not be an option. This consequence should be seriously considered during the design stage and should be avoided if at all possible.

13.2.5 Weather.
Weather is a factor that can significantly affect barrier costs, particularly in areas where highway construction and noise barrier construction are restricted or limited during certain seasons. In these areas, fabrication schedules must be timed to have material available in non-restricted seasons. A delay in the fall delivery of noise barrier panels or posts would likely delay barrier construction until the spring. Unseasonable weather can either help or hinder barrier construction: an unusually mild winter may allow for otherwise restricted activities to continue, while an unseasonably cold winter may delay the thawing of ground necessary for certain construction activities. All of these factors will affect the ultimate cost of the noise barrier.

13.2.6 Traffic Protection and Detours.
If traffic protection and/or traffic detours are a requirement, the cost of such protection may be attributed to the barrier cost. In addition, the contractor may charge a higher unit cost for barrier construction performed close to traffic as compared to construction in a less restricted area.

13.2.7 Limitation of Construction Hours.

• Traffic Related - Less efficient and more costly production can be expected when construction hours are limited or interrupted due to factors such as needing to keep lanes open during peak hours. Setup and knockdown time is costly and non-productive. If weekend or nighttime construction is restricted, it is possible that a project could take an additional construction season to complete.
• Due to Local Noise Ordinances - Similar types of inefficiencies (and associated increased costs) may occur in areas where local noise ordinances restrict the hours of construction.
• Proximity to Neighborhoods - Commitments made to communities to restrict either the hours of construction operations, the level of noise generated by such operations, or specific equipment used in the proximity of residential dwellings or other sensitive land uses will likely add cost to the noise barrier. Such increased costs can be related to items such as temporary noise barriers, quieter equipment, restricted operations, etc.
• For Specific Operations - Pile Driving, Blasting, etc. - Specific operations, such as pile driving, rock drilling, blasting, etc., may be restricted or prohibited on either a project wide or specific area basis. They also may be limited to specific times and noise levels. Where such procedures are the only available technique, these limitations will undoubtedly result in increased barrier costs.
• Interference with Utilities, Structures, and Other Features - Increased noise barrier costs will result if construction requires the relocation of utilities or special barrier designs to avoid utilities. In addition, the construction of a barrier parallel to and underneath an overhead power line will require specialized equipment to erect the barrier or may prohibit the use of lift-in panels. Cast-in-place barriers may be required in these areas.

13.3 Labor Costs
Labor costs vary widely from area-to-area and thus have a significant bearing on overall noise barrier costs. In addition, certain barriers can be erected using general laborers, while other systems may require labor with specialized experience and expertise. Barriers constructed in areas where union trade agreements are in place may require numerous union trades to be involved in the barrier construction; while construction of a similar barrier in a location not governed by such agreements may be accomplished with general laborers.

Section Summary