I all seriousness I don't recommend a knife for self defense in general. Before everyone gets up in arms I will explain.
The key to staying safe/safer is distance. If they aren't going to carry a gun the next best is pepper spray. You at least have 10-12 feet to spray and then move plus you can use it point blank. Then if they keep coming a knife might be handy since they(the bad guys)are no longer 100% combat effective. I carry one (a knife) at work as a last ditch. But it will be a unique situation if it comes to that.
The next issue is outdoors pepper spray can't always be used. You don't want to pepper spray yourself or someone with you by accident.
Being aware of your surroundings and situation goes along way in preventing any situation before it ever happens.
