In my town, they added a roundabout on a street, but didn't finish all the landscaping around it before opening it up for use. It had no reflective paint on it yet either and it was right after a slight decent in the road and wasn't really visible and two brothers riding their Harley's were hot-rodding down the street (screaming down at 100+ MPH) and they didn't see it in time and both launched into the air, hitting the curbs on the other side, killing both of them on impact.
They should NEVER have been going that fast down the street (new residential construction) but the city, in my opinion) didn't help things with the design and implementation of it either.
Now that it's finished, it hasn't been a problem, but I know the city still has a lawsuit against them for it.