You asked why the state no longer funds noise barriers along state highways. You also wanted to know whether it has been alleged in the past that they do not work effectively and who it was that concluded this.

SUMMARY

Connecticut continues to fund noise barriers along certain state roads when, as a result of a noise analysis, they are found necessary for mitigating increased noise as part of a road reconstruction or expansion project. The state generally does not fund so called “retrofit” noise barriers, which are barriers at highway locations where the road is not being reconstructed or expanded or when the buildings adjacent to the highway may have been built after the highway was already there.

State and federal regulation and policy separate noise barriers into two types. One type is required to mitigate increased traffic noise exceeding allowable levels that may result from new highway or bridge construction or reconstruction. The federal government requires this mitigation and generally will pay most of its costs as part of the approved project. These are known as Type I projects under federal regulations.

The second type of noise barrier project is one that is constructed as a stand-alone project along a highway or bridge that is not being reconstructed. These are known as Type II or “retrofit” projects. They are not mandatory under federal regulations and have generally been held to more restrictive standards with respect to receiving federal construction funds. When Congress passed legislation in 1995 establishing the new National Highway System, it completely banned use of federal funds on any Type II projects not already underway.

No specific source of state funding for retrofit noise barrier projects has been set aside since 1987. The legislature provided $ 5 million in transportation bonding in 1986 and $ 5 million in appropriations in 1987 specifically for noise barriers. Since that time a few additional projects have been done under the special road and bridge project component of the Department of Transportation improvement program. These projects generally fall outside available funding sources, but the legislature has taken the initiative to fund them. The last noise barriers funded as special road and bridge projects were finished in 1992. Since that time, the DOT has made it agency policy not to use any of its funding for noise barrier retrofit projects unless the legislature specifically provides funding for a project, and this policy remains in effect. Thus, any retrofit projects will probably require the legislature either to specifically earmark funds in addition to those the DOT already is using or to direct the DOT to build noise barrier projects instead of some other projects it has planned.

Noise barriers designed according to current acoustic design standards are typically capable of reducing noise levels at the row of buildings closest to the barrier by as much as 10 decibels. This equals a 50% reduction in the perceived noise at these locations. Depending on other circumstances, such as the height of the barrier and the distance between the barrier, the noise source, and other noise receivers, significant benefits can occur further away from the wall as well. Field tests of installed noise barriers, including earth berms, wooden walls, and masonry block or concrete walls generally confirm these effects.

The main critic of the effectiveness of noise barriers in Connecticut has been Professor Conrad Hemond of the University of Hartford's College of Engineering. His research was highly publicized during the mid-1980's. Hemond argued that even if a noise barrier produces the 10 decibel reduction it is intended and designed for, the noise may still be loud enough to interfere with sleeping and conversation.

Whether noise barriers are “effective” or not is a subjective judgment. Since the federal standards they must meet call for them to produce a 10 decibel reduction in noise at the row of noise receptors closest to the barrier, their ability to accomplish this purpose suggests that they are effective. However, if the expectation is that they should have a greater effect that this, one might conclude that they are ineffective.

BARRIER CLASSIFICATION—TYPE I VERSUS TYPE II BARRIERS

Both the Federal Highway Administration (FHWA), which administers the use of federal funds for highway projects that could include noise barriers, and the Connecticut Department of Transportation (DOT) distinguish between noise barrier projects by classifying them as either Type I or Type II barriers. The Type I barrier is included in a federal-aid highway project as part of the new construction of a highway on a new location or the physical alteration of an existing highway that significantly changes either the horizontal or vertical alignment or increases the number of through-traffic lanes. A Type II barrier is proposed for noise abatement on an existing highway. Type II barriers are commonly known as retrofit projects because the existing highway is retrofitted with a barrier without major reconstruction taking place (23 CFR § 772. 5).

A noise barrier's status as either a Type I or Type II project is critical to several questions, including whether its construction is mandatory or voluntary, which federal regulations apply, and whether it receives funding. Type I projects must be included in a project when the required traffic noise analysis determines that the construction or alteration of the highway or bridge will result in noise impacts on nearby land areas that exceed allowable levels determined under FHWA regulations and thus require undertaking abatement measures. Noise barriers are usually the type of mitigation selected because they are the most cost-effective. But other actions, such as noise insulation for buildings affected by the noise are also possible though rarely used. The noise barrier essentially becomes an individual element of the overall project, and it is funded as part of the project. Thus the primary source of funding for Type I projects is federal. Since most such projects occur along roads on the Interstate Highway System, federal funding usually covers 90% of the cost and the remainder is paid with state funds.

Type II retrofit projects are at the state highway agency's discretion and are not required by federal law in the same way as Type I barriers. Thus, the federal requirements apply only when the transportation agency elects to submit the project to the FHWA for federal funds approval. Federal funds availability for Type II projects has always been more constrained than for Type I projects and since passage of the National Highway System Designation Act of 1995 (P. L. 104-59) it has disappeared entirely.

Current FHWA regulations state that federal financial participation in Type II projects will not normally be approved for noise-affected activities and land uses that came into existence after May 14, 1976. But abatement measures may be approved and funded for such activities and land uses if local authorities have taken measures to exercise land use control over the remaining undeveloped lands adjacent to highways in the local jurisdiction to prevent further development of incompatible activities (23 CFR § 772. 13). In other words, the extent to which the locality has attempted to prevent noise-sensitive activities from being introduced around the highway might greatly affect whether the project receives federal funding.

The funding situation for Type II barrier projects changed significantly with passage of the National Highway System Designation Act. Citing a concern that increasingly scarce federal resources were being used to retrofit existing roads to mitigate noise rather than meet existing highway and bridge needs, Congress banned the use of federal funds on any Type II projects that were not already underway when the law took effect on November 28, 1995 (P. L. 104-59, § 339; 23 USC 109 note). In its report on the legislation, the House Committee on Transportation and Infrastructure expressed its greatest concern for situations where barriers were being installed on highways that are not being expanded and the residential development adjacent to the highway right-of-way occurred after the construction of the road (H Rept. No. 104-246, p. 62).

STATE FUNDS FOR NOISE BARRIERS

Noise barrier construction was an active component of DOT's transportation program from the early 1970s to the late 1980s, but the retrofit portion of the program essentially disappeared after 1992. Until 1981, noise barrier construction was basically confined to the non-toll portions of interstate highways. These barriers were funded primarily with 90% federal funding from the interstate construction program. But in 1981, the federal law was changed to require appurtenances such as noise barriers to be funded from the much smaller interstate rehabilitation category rather than the construction allotment.

Since available interstate rehabilitation allotments were already fully committed for highway and bridge rehabilitation and safety projects, the DOT considered these of higher priority and determined not to continue programming federal funds for noise barrier retrofitting for the foreseeable future.

As the retrofit program dwindled through the mid 1980s, the legislature attempted to provide it with new momentum through passage of SA 85-107. This legislation required the DOT to retest areas along state and interstate highways where noise barriers might be needed, revise its existing noise barrier construction priority list according to the new data, develop a 10-year plan for installing the noise barriers, and estimate the costs of designing and constructing the barriers on the list. The DOT identified 189 Type II retrofit locations and estimated that the cost of building noise barriers at all of these locations over a 10-year implementation period running from FY 1986-87 through FY 1995-96 would be $ 125 million.

The DOT did not propose funding for the program, but it was not required to by SA 85-107. The legislature authorized $ 5 million in Special Tax Obligation bonds for 1986 to begin the program (SA 86-391), but this was only half of what the plan identified as necessary for the first year. In 1987, the legislature provided another $ 5 million in appropriated funds rather than bonds. These are the only two specific funding authorizations that have ever been made for noise barriers.

The $ 5 million bond authorization provided the money to construct the first eight projects on the retrofit priority list (six on I-95, two in West Haven, two in New Haven, one in Bridgeport, and one in Fairfield; one on I-84 in West Hartford; and one on Route 72 in New Britain). The $ 5 million in appropriations covered construction of another seven barriers (Route 8 in Waterbury, I-84 in Southbury and East Hartford, two on I-91 in New Haven, and on I-95 in Stratford and Stamford).

The legislature has made no specific authorizations or appropriations for noise barrier retrofit projects since 1987, but a few projects showed up in the annual Master Transportation Plan for the next four years. They were programmed as Special Road and Bridge Projects, which was a funding category used to cover special projects of interest to the legislature but for which no money was available from existing sources. The last noise barrier projects funded as special road and bridge projects were in the 1992 Master Transportation Plan.

In 1992, the transportation commissioner, Emil Frankel, declared a moratorium on further programming of retrofit noise barriers in a letter sent to a legislator during the 1992 session. In the letter, he stated that the DOT's policy would be that no additional work would be done under the statewide retrofit program except for (1) barriers constructed under prior specific legislative authorization (the special road and bridge projects), (2) those required by the FHWA on Interstate reconstruction projects (Type I barriers), and (3) a project at the new weighing and safety inspection station being constructed on I-95 in Greenwich. (Letter to Senator Kevin Sullivan, dated May 18, 1992) Subsequent transportation commissioners have reaffirmed this position.

In 1997, DOT developed a formal policy and procedures for highway traffic noise impact analysis and abatement. With respect to Type II retrofit projects, this policy states that DOT will consider abatement of traffic noise along existing controlled access roads given these conditions:

1. Noise receptors (buildings or land uses such as parks) under consideration for abatement must have been in existence prior to the construction of the existing highway which has been identified as the major contributor to the noise climate due to traffic. Existence of noise receptors is to be determined by local assessor's records.

2. The existing outdoor noise level for the first row of receptors at the time of evaluation must equal or exceed 60 dbA.

3. A project priority ranking (based on the latest priority list for retrofit project locations) must be applied using the project priority ranking number based upon several factors including noise level, the number of receptor units built before and after the expressway, land use category, and the cost-effectiveness of abatement. Locations with combinations of high noise levels, dense population, and lower abatement cost would rank higher than those with moderate noise levels, sparse population density, and high abatement cost.

The policy also states that noise abatement is not considered to be reasonable under these circumstances:

1. Along existing uncontrolled access roadways

2. At locations where a barrier would pose overriding structural, operating safety, and maintenance problems

3. Along the Merritt Parkway pursuant to Merritt Parkway Working Group Guidelines

4. At locations where after local government consideration it is stipulated in writing by the chief elected official that the local government and 100% of the benefiting property owners (located within 300 feet of the nearest travel lane) oppose the proposed barrier

5. At locations where a minimum 7 db benefit in noise climate cannot be achieved with abatement for the first row of noise receptors at the center of the noise abatement system

6. At locations where the barrier height must be greater that 22 feet above ground elevation to achieve the minimum noise reduction of 7 db

7. Through the acquisition of private property

8. Through the application of sound proofing to private property

9. For corridors previously evaluated for noise impact in association with roadway construction or reconstruction projects

Finally, the policy states that funding for Type II retrofit projects must be approved by the General Assembly.

NOISE BARRIER EFFECTIVENESS

Noise barriers are primarily intended to reduce perceived highway noise levels for the homes closest to the highway. The sound attenuation effects of a barrier diminish with distance from the wall as the sound waves bend back to the ground. As the sound waves bend over the wall, the amount by which they diminish in intensity depends on the angle at which they reach the sound receiver. Thus, the overall attenuation effect depends on the interrelationship of three factors: the height of the wall, the distance between the noise source and the barrier, and the distance from the barrier to the noise receiver. Sometimes, the first row of houses also may act as a noise block for the second row. Distance from the highway can also reduce perceived noise because it tends to blend with other background noise.

A noise barrier that achieves a 10 decibel reduction in noise level at the row of buildings closest to the barrier is considered to be highly effective by most current design standards. (A decibel is the basic unit of sound measurement). Because sound is measured on a logarithmic scale, reducing the sound level by 10 decibels represents a 50% reduction in the perceived noise level at the point of measurement. This is an acceptable performance criterion according to federal noise reduction standards, which form the basis for most state programs. Field tests of noise barriers in Connecticut and elsewhere have been consistent with these general performance criteria.

When two noise barriers are parallel to each other on opposite sides of a highway, a problem can occasionally arise when sound blocked by one barrier reflects across the highway and increases noise levels on the opposite side of the road. But this problem does not occur automatically every time barriers are on both sides of the road. The overall distance between the barriers is the main determinant of sound reflectivity. Some states have experimented with introducing sound absorptive materials into their noise barrier designs as a way to handle this problem. California, Colorado, Illinois, Louisiana, Maryland, New Jersey, Pennsylvania, Tennessee, Utah, and Virginia have all constructed at least one barrier using such sound absorptive materials. Connecticut incorporated sound absorptive material in a section of a noise barrier along I-84 in East Hartford.

The best known critic of noise barriers in Connecticut was Professor Conrad Hemond from the University of Hartford's College of Engineering. In the mid-1980's, he published an opinion article in a construction industry trade magazine in which he criticized the cost effectiveness of noise barriers. He was also quoted extensively in a September 16, 1985 Hartford Courant article questioning their effectiveness. Hemond stated that noise barriers had a limited effect in an area 150 to 200 feet behind the fence and little or no effect beyond that distance. Within the area close to the wall, noise reductions of 10 decibels were possible, but because noise waves would come over the wall and bend back to the ground after that distance, they would still be high enough to disrupt normal activities. He also stated that any cracks in the wall or separations between the planks would allow the noise to come through at full strength.

Whether this means that noise barriers are not effective is a matter of opinion. State officials who worked with noise barriers countered Hemond's criticism with information showing that the barriers generally achieved the purpose for which they were designed; specifically, to reduce the noise at the first row of houses next to the wall by as much as 10 decibels. This reduction results in a 50% reduction in noise as it is perceived at these locations. Noise barriers are not intended to have a greater effect. They also added that since noise perceptions are subjective, the barriers have psychological benefits beyond their actual reduction of noise levels. For example, residents in areas near the barriers have commented that the fences increase their sense of privacy.

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