2.0    Environmental Noise Control Guidelines for Capital Works Projects
(Surface Transportation Corridors)

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Under the Environmental Assessment Act (EAA), all undertakings of roadways (including roads carrying bus transit vehicles only referred to as Transitways) and Light Rail Transit corridors, are subject to the requirements of the EAA. The assessments include noise and vibration impacts on noise-sensitive receptors.

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2.1    Purpose

To protect the public from exposure to adverse effects due to environmental noise and vibration, the City of Ottawa Official Plan contains policies and directives for noise from roads, rail lines and rapid transit corridors.

The guidelines presented in this section provide technical and administrative directions for noise assessment and control of capital works projects undertaken by the City of Ottawa involving the planning, design and construction of City surface transportation corridors. The projects include construction, reconstruction and widening of existing and new City roads and Transitways as well as Light Rail Transit systems in proximity to existing and future noise-sensitive land uses.

The noise assessment and control guidelines in this section should be considered as part of an integrated package for noise control in the City of Ottawa. The complementary noise control guidelines for City transportation corridors and traffic parameters are essential for achieving consistent sound levels of all new land use development, new capital works projects and Local Improvement initiatives that may be pursued by the City of Ottawa.

This guideline is expected to balance the need to have efficient movement of people and goods on City surface transportation corridors and the potential negative noise effects on the noise-sensitive receptors living and working in proximity to these systems.

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2.2    Scope

While the Environmental Assessment Act and the Ministry of the Environment guidelines do not provide distance setbacks within or beyond which noise assessments are to be prepared, the City is recommending that the necessary submissions address the noise/vibration potential due to roadway, Transitway or Light Rail Transit undertakings based on the following minimum areas of influence containing noise-sensitive receptors measured from the corridor right-of-way:

• 100 metres for an arterial road or a major collector
• 100 metres for a bus Transitway corridor
• 250 metres for a Light Rail Transit system corridor noise and 75 metres for its ground-borne vibration assessment.

A larger influence area may be necessary depending on the various corridor and traffic parameters and the significance of the ambient sound levels.

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2.3    Sound Level Criteria for Capital Works Projects

This Section contains the applicable sound level criteria, guidelines and other requirements when considering new construction, reconstruction and widening of City roads and rapid transit corridors in the City of Ottawa. It is based, in part, on the Ministry of Environment/Ministry of Transportation Noise Protocol, MOE guidelines and criteria, City of Ottawa Official Plan noise policies, City of Ottawa transportation planning and design practices and the former RMOC guidelines on City roads.

The following sound level criteria apply to vehicular traffic and bus movements on City roads and Transitways:

1. This Guideline applies to outdoor levels in the outdoor living area only.
2. The applicable sound level descriptor is the A-Weighted Equivalent Sound Pressure Level, Leq in dBA established for the daytime period from 07:00 to 23:00; also referred to as Leq _16hr, dBA.
3. The objective for outdoor sound levels is the higher of the Leq_16hr 55 dBA or the Leq_16hr ambient sound level that may prevail at the start of project construction (referred to in this document as the "established ambient").
4. The significance of a noise impact, also referred to as the 'excess' or 'change', will be quantified by comparing the future sound levels with the higher of Leq_16hr 55 dBA and/or the established ambient sound level.
5. Mitigation will attempt to achieve sound levels as close to the objective level as is technically, economically and administratively feasible.
6. The acoustic impact rating, the degree of effort applied and action for mitigation of the noise impact should conform to Table 2.1.
7. Where the future sound level exceeds Leq_16hr 55 dBA and the increase in the sound levels above the established ambient exceeds 5 dBA, the City of Ottawa will investigate the feasibility of noise control measures within the right-of-way and introduce appropriate measures such that, where feasible, a minimum attenuation (averaged over the first row of receivers) of 6 dBA can be achieved.
8. If the future sound level is greater than Leq_16hr 55 dBA and less than or equal to Leq_16hr 60 dBA and the excess or change in sound level above the established ambient is either:
• less than 5 dBA, then no mitigation is required; or,
• exceeds 5 dBA, then the sound level criteria in Clauses a) to f) above will apply at the sole cost of the City and within the City of Ottawa r.o.w.
9. If the future sound level is greater than Leq_16hr60 dBA and the excess or change in sound level above the established ambient is less than 5 dBA, the feasibility of noise control measures within the right-of-way will be investigated under the City of Ottawa's Local Improvements policy and guidelines. The barrier(s) will be maintained within the City’s r.o.w. The City prefers retrofit sound barrier walls at the flanking ends to be on City owned lands, however if required, property owners at the termination points of the noise abatement wall will be asked to register an easement to the City of Ottawa for the construction and maintenance of a noise wall along a side lot line. The side lot line noise wall will provide protection for the rear yard area of the adjacent property. If the landowner refuses to transfer the easement, the City will not attempt to purchase or expropriate the easement but will delete this section of wall from the noise abatement construction project.
10. Where the dominant noise source is due to transit activities within an LRT or a Transitway terminal, a rail yard facility to accommodate the LRT service yard, or a terminal building containing mechanical systems then the City of Ottawa will use the "Stationary Sources" criteria.
11. Alternative noise control measures shall be considered prior to making the decision to use barriers.

Table 2.1 - Summary of Impact Rating and Action for Mitigation

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2.4    Noise Impact Assessment for Capital Works Project

The sound levels should be established using prediction models acceptable to the City. Actual field measurements may be used subject to City of Ottawa's prior approval to deal with situations that may not be feasible to predict such as:

1. unusual traffic patterns or the presence of high percentages of vehicle classifications beyond those reported by the City.
2. traffic or corridor parameters that are outside of the limitations of the prediction model;
3. downtown core areas;
4. presence of large reflecting buildings in dense urban areas;
5. highly irregular topography;
6. the presence of other stationary sources of noise; and,
7. the presence of complicated geometrics for calculation purposes.

Actual field measurements, if deemed necessary, are to be performed in accordance with the MOE procedures and generally accepted acoustic and traffic engineering principles.

The following points should also be considered:

1. To determine the noise impact from a City Road or a Transitway, for each route alternative the smallest study area should be defined using one or more of the following methods:
1. using 5 dBA contour lines extending from the source to a noise-sensitive area where there is no increase above the ambient sound level; or,
2. a noise-sensitive area where there is no increase above the ambient sound level; or,
3. a perpendicular distance of 100m from the closest edge of pavement from arterial or collector roadway or Transitway r.o.w. (reference: Section 4.8.8 in the 2003 Official Plan).
4. 250 metres from LRT r.o.w.
2. The noise impact on noise-sensitive areas is to be determined for outdoor spaces.
3. There is no minimum number for residences that define a noise sensitive area. Therefore, all noise sensitive land uses, regardless of size or location, are to be assessed for potential application of noise control measures.
4. The ambient sound levels will be based on the expected road and traffic data at the commencement date of project construction.
5. Future sound levels from the project will be based on traffic projections corresponding to the mature state of development designated in the City of Ottawa's Official Plan.
6. Off right-of-way noise control measures and night-time (11:00 p.m. - 7:00 a.m.) assessment of the noise impact will not be considered as part of these City guidelines.
7. Notwithstanding the criteria for mitigation and the warrants for sound barriers, additional mitigation may be recommended to rectify inconsistencies such as surface repairs, speed reduction and repairs to manholes/catch basins.
8. Impact assessment ratings should be interpreted based on Table 2.1.

Figure 2.1 illustrates conceptually the time periods for noise assessment of a new capital works project.

Figure 2.1- Design Guidelines For Noise Assessment Of City Of Ottawa
Capital Works Roads And Transitways

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2.4.1    Surface Transportation Corridors Sound Level Predictions

With respect to surface transportation noise, the prediction methods accepted are outlined in the Ontario Road Noise Analysis Method for Environment and Transportation (ORNAMENT), Sound from Trains Environment Analysis Method (STEAM), or the computerized version STAMSON as updated from time to time. The models are suitable for vehicular traffic on roadways, for bus movements only between stations on Transitways and for rolling stock on rail lines.

For vehicular traffic and/or bus traffic on City roads and/or dedicated bus Transitways, the relevant vehicular, truck and bus traffic data should be entered with their appropriate parameters directly into the STAMSON program (using the “Road” template).

For light rail traffic employing diesel prime moving engines/locomotives, where used as City transit vehicles, the rail traffic data (available from the City) should be entered with their appropriate parameters directly into the STAMSON program (using the “Rail” template). The appropriate parameters from the City includes the “number of trains for time period”, “number of locomotives per train”, “number of cars per train”, and the “speed”.

For light rail traffic (LRT) employing electric prime moving engines, which is used as City transit vehicles, the LRT traffic data (available from the City) should be entered with their appropriate parameters directly into the STAMSON program (using “RT/Custom” template). The appropriate parameters from the City includes the LRT “emission level for custom type”, the “source height”, “number of vehicles for time period”, and the “speed”.

The report will detail information on all adjustments where applicable. Where there is more than one noise source, the calculation of the combined sound levels is required. When predicting the sound levels due to City roads, Transitways or LRT, the following points should be adhered to in the analysis and assessment:

1. For improved accuracy, curved road or rail sections with varying grade elevations, 4 and more lane roadways and roads with sound barriers are to be assessed on the basis of multiple segments.
2. Where sound barriers are involved in the analysis and especially where the existing and/or proposed grade elevations change considerably, sound level calculations should be performed at more frequent locations (preferably at every third dwelling unit/lot or less).
3. Every effort should be made to secure reasonable accurate grade elevations at the receptors, barrier base elevations and noise source elevations and to be included in the study. To establish the feasibility of noise control measures during the preliminary design stages of the corridor, the existing grade elevations may be used for relatively flat conditions. For sites involving difficult topographies (source, barrier and/or receptor locations), possible or preliminary grade elevations should be used. It is only in the detailed design stages of the corridor design process that noise assessments be updated to a greater detail based on reasonably accurate grade elevations.
4. The majority of barrier segments, where sound barriers are involved, should be in the acoustic "shadow zone". The use of acoustic "bright zones" is not acceptable except for the remote segments.
5. For roads and bus transit traffic, the "posted speed" limit should be used in calculation of the sound levels. Where it could be demonstrated by any of the concerned parties that the actual operating speed is significantly different than the posted speed limit (a change of over 5 km/hour for the 85th percentile of the speed), additional analysis should also be included in the study to deal with this change. For LRT, the system speeds shall be obtained from the transit authority in the City.
6. Where heavy truck percentage on City roads exceeds 5% of the total traffic volume and where sound barrier(s) is (are) warranted, additional and supplementary analysis should be included in the study by separating the analysis (sound level calculations) of each vehicle class separately prior to combining the sound levels of all vehicle categories to arrive at the overall sound levels due to all vehicle classes.
7. All receptors (residential and non-residential) that may have an outdoor noise sensitive land use component are to be identified and addressed in the study. The impact on noise-sensitive non-residential buildings that do not include central air conditioning are to be also addressed in the noise assessment.
8. Where the receptors are outfitted with existing sound barrier(s), the study should address the sound levels with such barrier(s). The general condition of the barrier(s) that affects their acoustic performance should be included in the noise study together with appropriate conclusions and recommendations.
9. Where the study is concerned with detailed construction of a Capital Works project, the study should contain additional and comparable details related to the construction phase noise including:
   • Prevailing ambient noise
   • Prediction of the noise due to various phases of construction (demolition/clearing, earth work, placement of sub base, paving, etc.) based on knowledge of the construction equipment to be used, various crew sizes, number of equipment to be used, etc.
   • Applicable provisions/sections in the City’s noise-by-law and applicable restrictions.
   • Special Provisions (SP) to be included in the contract documents to address construction noise and its mitigation, if required.
10. Bus stops, other than stations, do not have to be separated from the general noise produced by the bus movements between stations.
11. Transitway buses are considered "medium trucks" for Transitway sound level predictions except where it is demonstrated by the Acoustic Consultant that the specific bus emissions are similar to that of heavy trucks.
12. For a transit terminal or storage facilities which are considered by the MOE as a Stationary Source, other calculation routines and/or models must account for all noise events generated by a typical facility such as idling, acceleration and deceleration, and movements at different speeds within the facility. Factors affecting the overall hourly Leq due to a typical terminal such as the number and duration of each noise event must also be included in the assessment. Other sources in such facilities that should also be assessed include building mechanical equipment and parking lots, if applicable.
13. While the use of the AADT for noise assessments of road traffic is the common practice, special consideration may be given to situations where the weekend traffic or summer traffic (SADT) may be more dominant. Appropriate adjustments to the calculated sound level should, then be applied in such situations. The results and recommendations in this respect should be implemented.

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2.4.2    Ambient Sound Levels Due to Other Sources of Noise

Ambient sound levels due to other sources of noise (such as Highways under the MTO jurisdiction or major commercial or industrial areas) will be established by procedures acceptable to the City. A combination of prediction and/or measurement procedures may be required by the City of Ottawa depending on the source of noise.

Reference should be made to applicable MOE guideline publications and procedures.

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2.4.3    Impact on Future Committed Noise-Sensitive Developments

This section applies only to already committed noise-sensitive land uses or to new land use proposals that have already been submitted to the City for approval.

In the course of preparation of a noise study for a capital works project, it is essential that the Engineering Consultant contracted by the City of Ottawa obtain information from the City of Ottawa on future development applications in proximity to the proposed City Road and/or Transitway undertaking for further examination. The information should include copies of the relevant plans, status of approvals by the approval authorities, existing or proposed grade elevations of the proposed development, copies of noise study reports that may have been submitted by the proponent to the approval authorities and any other relevant information.

The Acoustical Consultant engaged as part of the consulting team should review all the relevant information in these documents for noise, such as the road and traffic data used by the proponent and/or their consultants, grade elevations of the road, predicted sound levels and their recommended noise control measures. The results of this review should be compared with the relevant technical details related to noise assessment of the subject undertaking and differences or inconsistencies; if any, should be noted and then reported.

The City of Ottawa should be advised of any discrepancies in the resulting sound levels and the extent of noise mitigation for both; the development side and the subject undertaking. Appropriate decisions must be made and an appropriate course of action be taken to correct any misgivings that may jeopardize or compromise the City's policies for noise.

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2.5    Noise Control Measures for Capital Works Projects

For new construction, reconstruction and widening of facilities within City right-of-way, there are a number of potential geometric and physical noise control alternatives available, including:

• selection or alternation of a horizontal alignment;
• depressed or elevated corridor profiles;
• earth berms;
• a combination of berms plus walls on top,
• traffic management,
• reduction or establishment of suitable vehicle speed limits,
• prefabricated noise barrier wall systems,
• For LRT, there are a number of improvements that may include the use of all welded rail sections, construction details related to future concrete rail structures that accommodate noise control parapet walls, vibration isolation of certain track sections and the choice of low sound emission LRT vehicles, and
• Any combination of the above.

The City of Ottawa will provide, where appropriate and feasible, noise control measures within the right-of-way.

Where construction or expansion of a City roadway or a Transitway is planned, and where future noise-sensitive development is likely to materialize, non-structural noise controls will be investigated, e.g. with control of vertical and horizontal alignments, to minimize noise impacts provided that significant increases in project costs or subsequent maintenance costs will not be incurred. Notwithstanding the above, it is still the responsibility of the developer to meet the City of Ottawa noise policy for new noise sensitive developments.

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2.6    Implementation Process for Capital Works Projects

This section provides the framework for the implementation of the City noise policy based on the established Municipal Engineers Association (MEA) and Provincial procedures. The primary objective of the implementation guidelines is to assist all concerned parties with City undertakings that are subject to this policy in the preparation, review and approval of roadways and Transitways noise assessment studies.

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2.6.1    Phases for Planning, Design and Approval for Surface Transportation Environmental Assessments

In addition to the MOE Guidelines for full EA’s, the Municipal Engineers' Association (MEA), in co-operation with other Provincial agencies has developed a guideline document to assist in the planning and design process for Class Environmental Assessment type municipal projects. The MEA document has been used extensively by the City of Ottawa and the Consulting Engineers when preparing City E.A.'s for roadway projects.

The planning and design process for Class Environmental Assessment for Municipal Road Projects prepared by the Municipal Engineer's Association recommends several phases for undertaking the assessments. Some of the phases will have linkages with the noise assessment process for roadway and Transitway projects undertaken by the City of Ottawa.

For environmental noise assessment purposes, it is expected that the same Class EA assessment process for road projects be also suitable for full assessments of LRT undertakings under the authority of the Environmental Assessment Act; the technical assessment procedures will remain unchanged.

It is therefore essential that all work related to environmental noise assessment link-in with the relevant phases of the EA process shown in Figure 2.2.

Figure 2.2- Environmental Assessment Planning And Design Process

The following points summarize the key elements of a noise assessment study of a typical surface transportation corridor project, which may be linked with the overall EA process (the numbers shown correspond to the comparable stages/phases):

Phase 1

Preparation of the terms of reference for a noise study.

Phase 2

• Examination and mapping of the existing and approved future noise-sensitive land uses
• Preliminary analyses of the ambient and future sound levels with the undertaking for the alternative solutions.
• Preliminary noise impact assessment and ranking of the alternative solutions should be performed based on scientific procedures for difficult projects (e.g. numerous receptors, distance variations, changing corridor parameters, different ambient noise, etc.), or based on counts of noise-sensitive buildings for simple projects.

Phase 3

• Examination and mapping of the existing and approved future noise-sensitive land uses.
• Detailed analyses of the ambient and future sound levels with the undertaking for the preferred design concept.
• Detailed noise impact assessment of the preferred design concept and investigation of noise control solutions.

Phase 4

Prepare the necessary noise assessment report for inclusion as part of the Environmental Study Report.

Phase 5

• Primary application: new surface transportation projects adjacent to existing noise-sensitive developments.
• It could be viewed as the reverse of Publication LU-131 which deals in part with new residential developments adjacent to existing surface transportation (with numerous differences).
• The primary criteria to be based on the City of Ottawa ENCG and other relevant MOE guidelines.

Documentation of the above noted phases of a noise assessment should closely follow that required by the Class EA process for each phase.

For road reconstruction or expansion projects which have existing reverse frontage/flanking, noise abatement features will be considered as part of the public consultation process under the Environmental Assessment Act or the Planning Act. The noise abatement features will be designed to abate noise generated from the future traffic projections of the "Horizon Year" established by the City of Ottawa.

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