I want to start running but worried about the area I live in being safe?

Pepper spray is pretty effective. I would suggest a pepper spray as they are light, easy to use and very effective. I would stay away from the knife as it is possible that an attacker could take the knife and you could be seriously injured or killed. With a knife you need to be too close to use it - very risky. A pepper spray usually works at about 15 feet away giving you valuable distance from an attacker.