Once-per-year cyclist counts by local governments and advocacy groups are severely affected by weather, and correction attempts for that are always going to be controversial. Bicycle-specific, 24/7 measuring devices are not cheap, but can provide useful data at choke points. All of the reasonably careful studies that Minneapolis and a few other places do are hard to generalize to other cities.
Paired city comparisons like the quickie I did a page ago seem compelling to me, but not necessarily to advocates of other points of view.
My basic conclusion is that we can infer trends and effects, but can probably never convince the absolutists on other side. But I do think I answered the OP with a solid example, so my work is done here :).