I don't believe sharrows are sensible on busy streets.
However, there are some benefits to put them on low traffic, mostly through streets.
Sharrows, signs, whatever, help cyclists find those streets that are good to ride on. And, perhaps get enough cyclists on a road, and some drivers would start only using that road for "local traffic".
I thought Alder Street in Eugene between 24th and 30th had them, but I'm not seeing them on the latest Google Maps. Nonetheless, it is good marking for a mostly through sleepy residential street.
Portland likes them. One of the better ones is Ankeny Street in East Portland. Pretty long. One block away from the busy Burnside.
https://www.google.com/maps/@45.5221...7i13312!8i6656
It looks like they also dropped in a few planters in key locations.
I find the speed bumps are annoying, and they've ground off a few of them.
Cars do seem to respect the bikes on that street, and it is a good street to ride on.
I really don't care about road placement, and don't believe cyclists should be taught to aim for the arrows, but rather to "share the road", adjusting road position as is appropriate.