<boggles>
Are bikes allowed to take the slip?
If so, how do drivers know if you're going to?
If not, that is an unusal situation - the UK equiv would be a slip-road to leave a DC A-road to get onto a motorway (or no-bikes-allowed Aroad).
That slip looks like a (typically US) very slow tight turn compared to UK junctions - what speed are cars slowing to in the absence of bikes?
No, bikes not (generally*) allowed on the freeway, so the cars know you're not going that way.
You have a good point about the slow/tight nature of it. This would account at least in part for the difference.
* - bikes are allowed on freeways where there's no reasonable alternative, so some remote out of town ones do allow them when there's basically no other option to get to a destination.
