None of the articles that quote that number provide a source, but if you need some support, here's what I found with 10mins of googling, TL;DR: the data they used is biased towards pro bike usage because they used a peak bike usage month (September). It also looks like they compared rush hour cycling usage to average car usage (although you can't tell that for certain from the source).

I think this is the source (page 2) of the numbers in the article, and guess what? The numbers cited in the article are perhaps unsurprisingly pro-cycling biased from the get go, note the qualification about the different time periods from when the data was collected "Bike counts taken on a weekday evening in mid-September 2019. Car counts from February 2018. Transit data from 2018 " Further, it looks like they compared rush hour cycling usage to average car usage (although you can't tell that for certain from the source) : https://www.cambridgema.gov/-/media/Files/Traffic/2023/hampshirest/hampshirestreetprojectbrochureonline.pdf

Proof of bias because of seasonal effects: p. 3 (showing January counts falling to less than a third of peak trips in September) . Note this data isn't specific to Hampshire St., but the seasonal trends are clear enough Jhttps://www.cambridgema.gov/-/media/Files/CDD/Transportation/Bike/EcoCounter_Trends.pdf

Don't forget to downvote for increased visibility! I know facts are scary to the mob.