Possible Clues:

• Learner driver accused, getting lost in blind alley
• 'There's only one way in and out (3,2,3)'
• Cad's clue is dreadful -- it doesn't get you anywhere
• Driver's dead end
• Road with only one entrance-exit
• Falsely accused learner in dead end
• A street with only one entrance-exit
• Copper goes to Longford with disastrous case that's going nowhere
• Such a road leads nowhere
• There's no going through it by the way