Hello,

Speed tables should better not be tagged as nodes on the road.  Do this only to mark a small speed table on the intersection point itself.

For a long speed table spanning across the entire intersection, it is better to split the road on the two limits of the elevated part, and then add the "traffic_calming=speed_table" tag on the road itself.  That makes it easier for route navigation and also allows to calculate statistics about infrastructure more correctly (one speed table here, not two).

Hope this helps.