Not sure how to fix bridge mapping for side street

Greetings,

Fairly new to OSM and I found a bug that I don't quite know how to fix. I have been reading about the different ways of mapping a bridge, but I don't see what is wrong.

Here is the issue: http://www.openstreetmap.org/#map=17/38.93105/-94.64582

Lets say you are leaving Roe Avenue to go west bound on 435. There is a on-ramp that has a divider between the on-ramp and the highway; This is the northern most highway traveling west bound on the map. That on ramp is shown correctly on the map that it goes under Nall Avenue then merges.

However, if using the route calculation it /really/ wants you to exit at Nall, sit at the light, then merge back onto the on-ramp before merging onto 435.

It is like it doesn't see and or recognize that instead of taking the right exit, you can (and should!) go straight under the bridge.

I poked around at the map and looked at the documentation, but I completly fail to see why this exit is an issue.

Can anyone provide any feedback on the issue and how to fix it?

Thanks!