All the major roads do bypass Hoboken, but I seem to remember you can get to the Lincoln Tunnel from Route 139 through that city. Some use it as an alternate and at one time there was a sign at Jersey Avenue for the Lincoln Tunnel with follow up signs throughout Hoboken telling you what streets to use. Don’t remember which I used except for the 14th Street Viaduct, as that does stand out from the rest.
Of course this was over thirty years ago, so traffic volumes might of increased since then, but I’m sure there are some that might use it still to avoid Route 495 through Union City.
However 20 mph is better than slow crawl on 495. So I imagine those folks aren’t complaining.