TIS and What could have been

"Chuck" wrote in message
oups.com...
Unnerveing thing happen to me today.
I have TIS displayed on the Garmin 430.
I was 15 or 20 miles north of Moraine (I73) in southern Ohio and
talking to Dayton Controller under Flight Following.
I'm at 4500 ft and landing at Moraine. I request (I'm in his air
space) the controller that I would like to start my decent and he says
cleared to decend. Shortly, the display squacks and says "traffic" and
I see a traffic indicated at 500 ft below. I tell controller that I
have traffic on my display 500 ft below and he says "Yes, it is a 172
going into Moraine also."

So you were overtaking the 172? Did you not see him prior to descending?