As a general rule, local emissions profiles (whether through Snapshot or other programs) are not appropriate tools to monitor the impact of a project. The impact of community or council-led projects will generally fall within the margin of error of an emissions profile. This should change over the coming years as the data improves and the scale of projects ramp up.
Tier 2 data, such as for municipalities with transport data provided by Google Environmental Insights Explorer (EIE), can be used to track trends in emissions specific to your municipality. In this case the impacts of large-scale projects or programs such as significant infrastructure upgrades may be visible. However, a further layer of analysis would be needed to control for other influencing factors (such as the Covid-19 lockdowns).