Traffic vibration: road surface quality drives vibration impacts

Transportation -- both road and rail -- is one of the most-important contributors to environmental vibrations in well-designed research and development settings. It should be no surprise that a few rules-of-thumb prevail when it comes to traffic impacts on labs:

• heavy trucks create more ground vibrations than do lightweight cars

• faster vehicles lead to greater impacts

• nearby roads are more important than distant roads

Just how much vibration impact can traffic create? We produced this video (see below) at a large research institution in North America to show how significant it can be. In this case, delivery traffic on an alleyway risks unnecessary vibration impacts to a proposed electron microscopy center in a lab to be built just off that alley. The vehicles are heavy (trucks); they are pretty fast; and they are at very short setback. But most importantly, a poorly-paved section of the alley makes things worse.

It's important to understand that those impacts are largely driven by imperfections in the road surface. If we had perfectly-flat roads—without potholes, seams, or other vertical discontinuities—then traffic impacts would be greatly reduced. "Perfect" roads are an impossibility, but that doesn't mean we can't maintain those driving surfaces near vibration-sensitive facilities like laboratories. Most lab owners don't have direct control over city roads or nearby highways, but they certainly have control over their own campus roadways. Minimizing vertical discontinuities can lead to huge improvements. And whatever you do, don't use speed bumps!