Angels on Earth

A story about a co-worker's recent adventure:

Traffic was heavy as "DJ" and his wife sped down the highway with a trailer over-flowing with firewood which they'd picked up free just for driving a couple hours out of their way. They were tired; they were heading home.
They came up on a slow-moving vehicle, but since traffic was crowded, they could not pass. So they slowed also, and crawled along behind the car.

Many miles later, the slow car took an exit.
But almost immediately, a large white van pulled into DJ's lane and slowed down as well.

"What gives?" DJ wondered. "He sped up to pass me, and then slowed down? (insert various expletives)!"
DJ's wife agreed.

But again, with nowhere to turn, they puttered along behind the slow-moving vehicle.

Finally, DJ's exit came up. As they turned off the highway, DJ and his wife watched the white van continue up the highway.

"What was that about?"
"I don't know."

Then they heard the explosion!

A tire on their fulled loaded trailer had popped!

They limped to the side of the road and assessed the damage and tried to figure out how they could possibly get home now.

Suddenly, it occured to DJ:
If they had been flying down the highway as fast as they had wanted to be traveling, almost surely the tire would have exploded sooner... at full speed... with all that wood piled in it... in heavy traffic.

They both looked up at the highway where they'd last seen the white van disappear.
Had a terrible tragedy, not just for them but also for the other drivers, been avoided thanks to those two slow vehicles?

Had they just encountered an angel?
After all, the van was white...

What do you think?
Have you ever encountered angels on earth?