Yes it is the energy emitted by the words. The Hindus use the word AUM, which is the Sacred Sound Syllable. It's the most complete expression of vibration the voice is capable of. Try it, but do it very slowly and notice how the vibrations begin very deep in your diaphragm and end up on your lips.

Energy is neither positive nor negative, it has no polarity as such. When energy flows it's because there's a difference between where it's flowing for and to.

What are the reasons you're cussing other drivers? What are your subconscious intentions and reasons for your actions? Do you do it because you're judging the driver against the rules of the road and sensible driving, or are you expressing your fear they might cause an accident? Do you have the expectation that everybody should be considerate and if they're driving badly, does that contradict your expectations? Are you not yet aware of the reality that there are people who don't give a stuff, and what are the reasons you haven't 'adjusted' accordingly?

If you're prepared for people to do something stupid you're seldom disappointed, and when someone does something nice it's a treat. And it makes you a better and more aware and attentive driver, not being complacent. That will 'spill over' into your Spirituality.

While you hold to your belief - and until you have a meter it is a belief - that it's negative energy, if you asked those questions and came to realisations because of the energy does that make it positive? That will 'spill over' into your Spirituality too