Northbound I-75

I had a dream
that my husband and I
were in the car
headed north on I-75.
He was driving.

We were on our way to Detroit.
I needed to be somewhere,
I don't know where,
and he was driving me there.

As we got on the bridge
I noticed that there was
a bit of trouble on the southbound side.

There was not an accident.
Nor was there a back-up.
The cars just seemed to be
moving over
to another lane
all at once.

And then I noticed
that the edge of the bridge
was collapsing.
The cars were trying to
get out of that far lane
so as not to go down with the bridge.

It was only the far lane
was falling down.
The rest of the bridge seemed fine.

As I looked in the rear view mirror
I could see the edge of the bridge
just crumbling away.
But the northbound lanes were fine.

Once we got off at our exit
the entire bridge just collapsed.

So,
what does the collapsing bridge represent?
Why were we save on the northbound side?
Why was it only the edge of the bridge at first,
before the entire sudden collapse of the bridge?
Why did we witness the danger,
but were spared from it?