Longmeadow Parkway Will Be Very NOISY!
Summary – Longmeadow Parkway will greatly increase noise levels in the corridor. The noise levels within 150 ft. of the road will be equivalent to that of a DC-9 jet aircraft during take-off. KDOT is using a regulatory “trick” to avoid complying with current noise regulations. Investigation of the potential use of noise barriers show that they will be ineffective in reducing noise levels.
The Problem – The noise from the new highway will be an issue for residents all along the corridor, but it will be especially problematical for those near the Fox River. The preliminary engineering plans for the road show steep slopes as it approaches the river. The road slopes at a grade of 5% which is a steep hill. The road will be traveled by a significant number of heavy trucks, including heavily laden gravel trucks from the nearby quarries. The drivers will throttle up to full power to climb the hill, and may use “engine braking” on the down slope. The noise will be intense.
Science of Noise – Noise is a very complex technical subject, and people vary in their sensitivity to it. Noise level is usually measured in decibels (dba) on a logarithmic scale. Going from 50 dba to 60 dba is a tenfold increase in sound level; going from 50 dba to 70 dba is a 100 fold increase. A 3 dba change in sound level is perceptible to most humans. Prolonged exposure to 90 dba or above is often considered a health risk.
The attached diagram (Exhibit A) shows noise levels for common situations. It was prepared by Landrum & Brown, an internationally recognized noise consultant, for the O’Hare Modernization Program where noise is a major issue. The diagram was copied from the Chicago Dept. of Aviation’s website which has a great deal of information about noise. Because of increased airport noise at O’Hare, the City of Chicago is insulating the homes of residents who will be exposed to noise levels exceeding 65 dba.
Longmeadow Noise – Using the diagram as a point of reference, it shows that the noise level of a diesel truck at 150 ft. is about 85 – 90 dba. This is comparable to the noise emitted by DC-9 jet aircraft during takeoff, or standing within 3 ft. of a kitchen blender or a gas lawn mower.
The original environmental studies for Longmeadow showed that noise levels near the river would only reach levels of 50 – 69 dba (Exhibit B-1). This seems low in view of the exposure. It may be due to the fact that the receptors (residents) were not expected to live near the road, or to lack of acknowledgement of the steep slopes or type of traffic. One cannot know without reviewing the date from actual studies which are not readily available.
It is interesting to note, on Exhibit B-2, that the original studies did look at the possibility of constructing 18 ft. high noise walls to protect residents. The studies concluded that even walls of this height would be ineffective in reducing noise levels.
KDOT’s Regulatory “Trick” - The investigations for the Longmeadow Parkway Environmental Impact Statement (EIS) were done in the 1995 – 2000 timeframe. Since that time many things have changed in the environment, and also in the laws and regulations governing the many issues surrounding the road. The regulatory bodies recognized that an EIS could become out-of-date if much time passes between the completion of the environmental work and the implementation of the project. An EIS usually must be re-done if 3 years have passed. The EIS for Longmeadow was completed in 2002; it is thirteen years old.
Many agencies will accept ”informal” processes for updating an EIS with memoranda or even e-mail on specific subjects. This avoids the rigorous, transparent public process for assessing environmental impact envisioned by the National Environmental Policy Act, the basic law that protects or environment, but it is expedient for agencies that don’t wish to be burdened by public input. It is allowed by the FHWA, and it is the procedure KDOT has been using for Longmeadow. KDOT specifically employed this procedure to avoid compliance with current noise regulations.
New, more stringent noise regulations for highways were enacted in 2011. KDOT apparently did not wish to be required to comply with these standards, so they asked for an exemption from IDOT. Exhibit C is a copy of an e-mail from IDOT which allows KDOT to sidestep the new regulations. Their reasoning was that since the environmental studies were done under the old, less stringent regulations, KDOT was exempted from compliance with the new, tougher regulations. This may solve KDOT’s compliance problem, but it won’t do much for residents along the corridor.