What was the speed limit on the Chain of Rocks bridge in St Louis?

[bugo]

I walked out to the bend of the CoR bridge at the St Louis roadmeet (shame on you who missed it, it was the best part of the meet) and couldn't help notice how sharp the bend is and how narrow the roadway is at that point. At the bend it gets slightly wider, but probably not wide enough for two full sized cars to go around the bend at the same time.  It is not possible for two semi trucks to go around the bend at the same time. How did they regulate the bridge? What was the speed limit? I can see it being as low as 10 MPH. Was there some sort of warning system near the curve? I saw some weird looking electrical outlets on the superstructure above the roadway.

[Rushmeister]

I saw some weird looking electrical outlets on the superstructure above the roadway.

I remember seeing those, too, when I was there a few years ago.  At the time I figured they were for overhead light fixtures. Maybe someone here knows for sure...