An officer and a DUI

Having had a good lashing of booze at a village pub, a good local boy gets in his car to drive home. He's swerving all over the place, barely missing tree after tree. A police patrol spots him, pulls him over and ask the man to step out of the car.

"Excuse me sir, we have reason to believe you have been driving whilst under the influence of alcohol and will need you to submit to a breathalyser test. Please put your mouth over the mouthpiece and blow in hard until I say stop" the officer recites.

Our boy thinks quickly
"I can't do that I'm afraid officer, I have sever emphysema from working in the mines, and cannot exhale strongly for any amount of time that would be useful to yourself and your instrument"
The officer thinks for a second, and accepts the man's excuse.

"In that case sir, we'll need you to provide a urine sample so we can gauge your alcohol level"
Again, thinking on his feet
"I'm terrible sorry but I can't do that either, I have an enlarged prostate and can't pass urine so easily. Indeed, I require the use of..."

"Ok, ok", says the officer, "in that case we'll need to draw a blood sample to be analysed"
Things are getting difficult, but the man comes up with another excuse!
"It is with great chagrin that I cannot oblige" explains the man "suffering from haemophilia, a single pin-prick can cause me to bleed for days. It is quite awful"

The officer has had about enough and goes to his car and bring back a piece of chalk. The officer proceeds to draw a white line down the side of the road about 20 feet long.

"Ok sir, I'll need you to walk down this white line I've drawn, right to the end, and then back again" demands the officer.
"Oh I'm afraid I can't do that either"
"And why not, sir!!?" exclaims the officer.
"Well, says the man, that's because I'm f*****g hammered!"