"BeepBeep" joke

A hip young man goes out and buys the best car available: a 1997 Turbo BeepBeep. It is the best and most expensive car in the world, and it runs him $500,000. He takes it out for a spin and, while doing so, stops for a red light. An old man on a moped (both looking about 90 years old) pulls up next to him. The old man looks over the sleek, shiny surface of the car and asks, "What kind of car ya' got there, sonny?"
The young man replies, " A 1997 Turbo BeepBeep. They cost $500,000." "That's a lot of money." says the old man, shocked. "Why does it cost so much?"
"Because this car can do up to 320 miles an hour!" states the cool dude proudly.
The moped driver asks, "Can I take a look inside?" "Sure", replies the proud owner.
So, the old man pokes his head in the window and looks around. Leaning back on his moped, the old man says, "That's a pretty nice car, all right!"
Just then, the light changes, and the dude decides to show the old man what his car can do. He floors it, and within 30 seconds the speedometer reads 320 mph.
Suddenly, he notices a dot in his rear view mirror. It seems to be getting closer! He slows down to see what it could be and suddenly, whhhoooooossshhh! Something whips by him, going much faster!
"What on Earth could be going faster than my Turbo BeepBeep?!?" the young man asks himself.
Then, ahead of him, he sees a dot coming toward him. Whoooooooosh! It goes by again, heading the opposite direction! And, it almost looked like the old man on the moped! "Couldn't be," thinks the guy. "How could that funky old moped outrun my Turbo BeepBeep?"
Again, he sees a dot in his rear view mirror! Whooooosh Ka-BbbblaMMMM! It plows into the back of his car, demolishing the rear end. The young man jumps out, and, Good Gravy!!!, it IS the old man!!! Of course the moped and the old man are hurting for certain. He runs up to the dying old man and says, "You're badly hurt! Is there anything I can do for you?"
The old man groans and replies, "Yes....... You can unhook my suspenders from your side-view mirror!"