What's behind the fence?

The M25 and the M6 are in the pub having a pint together and they are discussing who is the hardest, toughest motorway out of the two of them. The discussion soon degenerates into an argument.
"Well, I am obviously the hardest", says the M6, "I have hundreds of thousands of cars on me everyday and I go on for miles and miles."
"That¹s nothing," replies the M25, "Everyday I have hundreds and thousands of cars parked on me everyday and I handle it like it was nothing."
Just as he said that, Red Tarmac walks into the pub. The M6 runs off and hides under a table. The M25 looks on, a little confused.
Red Tarmac stands at the bar and orders himself a pint. He swiftly drinks his pint and leaves. Once he has left M6 comes out from under the table.
"What was all that about?" asks the M25, "I though you were supposed to be a really hard motorway."
"I am" replies the M6, "But he's a cycle-path!"