Walking on a quiet street at night is also pretty safe, you simply have to have an opened pocket knife ready in your pocket and poke it at anyone that come into your comfort zone. Alternatively, if you see anyone suspicious, just lick on your pocket knife with your tongue like a pervert serial killer, the subject will usually go away. But don't do this in front of the police, they will shoot you.
(some or all of the description above are merely the imagination of nil)