Industries
Transportation noise and vibration
Transportation infrastructure is what makes a region work. Highways, rail, transit and airports move the people and goods an economy runs on, and these projects need to get built. The case for them is rarely the hard part. How they sit alongside the places they run through is.
Noise and vibration is usually where that gets settled: whether a project is approved, what mitigation it carries, and what can be built beside it afterward. Getting it right is worth real money in both directions. A conservative prediction builds barriers that were never needed, or writes off land that could have been developed. An optimistic one gets caught at review and costs a year. The value of an experienced acoustician is that the number is right the first time and holds up when it is challenged.
Our experience
The engineers at Bentham have worked as acoustical consultants on transportation projects on both sides of the corridor, principally in Ontario and with road traffic noise work in British Columbia, Saskatchewan and Quebec: provincial highway projects, municipal and regional roads, rail and transit corridors and stations, and airports, alongside the developments and landowners those corridors affect.
On the agency side that has meant widenings of provincial highways across Ontario, predicting future traffic noise at adjacent homes, assessing the need for mitigation under the MTO and MECP guidelines, and designing the barriers themselves. Barrier design is where the assessment stops being a document, because location, height and extent have to deliver the guideline sound levels while remaining buildable at a cost the project will bear. The barriers that came out of that work met those levels at the communities behind them.
Stations are a different problem from corridors. Preliminary design work on deep subway stations turned on speech intelligibility from the public address system in very large volumes, where the reverberant field, not the equipment, decides whether an emergency announcement can be understood.
The construction phase is the part most often underestimated. Road projects bring heavy equipment, compaction and night work close to homes and to structures that may not tolerate it. We prepare construction noise and vibration studies that predict the impacts, set the limits and the monitoring, and recommend measures that let the work proceed, so the contractor knows where the line is while there is still time to change method. On the projects we have monitored, the work stayed within its limits.
Bentham Acoustics is new. Its engineers are not. The projects described here were carried out by Bentham engineers over their careers, at this firm and before it.
A full list of relevant project experience is available on request.
What we work on
Both sides of the corridor.
We assess what a new or expanded transportation facility does to its neighbours, and what an existing one does to a proposed building. The methods are shared, the interests are not, and having worked from both positions is what makes an assessment hard to argue with from either.
Rail noise and vibration together.
Vibration reaches buildings that look far enough from the tracks, and it is the one most often picked up late. Assessed alongside the noise rather than after it, the mitigation gets designed into the structure instead of retrofitted into a building that is already priced.
Aircraft noise and NEF contours.
We develop Noise Exposure Forecast contours for airport operators, and we assess development on land the contours affect. The contour governs what can be approved around an airport for years, so it is worth understanding properly from either side of it.
Barrier cost decided on evidence.
Mitigation is triggered by thresholds, and whether a receptor clears them is a modelling result. Accurate prediction is the difference between a project that carries barrier cost and one that does not, and it costs a small fraction of a barrier.
Land that stays developable.
Coarse assumptions sterilise property unnecessarily. A detailed assessment often shows that a site written off on a screening can be built, with mitigation that is proportionate rather than defensive.
One team from assessment to opening.
These projects run for years and the assessment gets revisited at every stage. Carrying it through design, construction monitoring and post-construction measurement means the assumptions are not relitigated by someone new each time.
Standards and requirements in Ontario
Road projects are assessed under the MTO Environmental Guide for Noise. Rail and transit work from the MOEE and GO Transit protocol and Metrolinx’s design guidelines, with acoustical studies required for development within 300 metres of a Metrolinx corridor and vibration studies within 75 metres. Aircraft noise is governed by Transport Canada publication TP 1247 and the Noise Exposure Forecast system, with new residential development not considered compatible at NEF 30 and above, a threshold carried into Ontario’s planning system directly.
New sensitive development near corridors is assessed under MECP publication NPC-300. Construction noise falls under MECP publications NPC-115 and NPC-118 and municipal by-laws, and construction vibration under municipal by-laws. Vibration limits for new development near rail are not set by MECP or most municipalities, so the criterion is established by the assessment rather than given to it.