No, unfortunately not. Getting traffic data would mean users volunteering to share location data, would need a centralized system to process everything, and would need a critical mass of users sharing said data to be anywhere near useful. The other possibility would be to pay for data from a provider like Google under an enterprise license that doesn't require sharing data back, but I don't know if that is even an option.

For now, I use both on my phone. I use OSM when biking or walking, I use Google Maps when driving, and I use my local transit web app when taking transit. I plan to switch my Pixel phone to GrapheneOS and to sandbox Google services that I still need. That being said, the ultimate way around needing traffic information is to try to live in places and in such a way that driving is not very necessary, but I know that is a huge ask for a lot of people.

EDIT: To be clear, MagicEarth does have live traffic as @[email protected] pointed out and is based on OSM, but is not itself open source.