When someone cuts you off while driving, let your anger follow them - forget about them.
Now, as for keeping from falling asleep - practice practice practice.
Once I was able to shift back and forth between consciousness and unconsciousness. My mind was fully awake, yet I could not feel my body at all. I could drift off into a dream and watch as a complete 3-dimensional world was being creating before me in one master artist's brush stroke - a world with individuals, scenerios, plots - more than a book could ever represent. Before I 'fell into' this world - I pulled myself back without 'waking up'. Then, I allowed myself to drift once more, and a whole NEW world was created. I pulled myself out the second time, and woke up.
It is tough stuff - you should never meditate with aspirations of achieving some kind of enlightenment or vision. Instead, your goal should be to merely relax, and to practice siliencing the voices in your head.
If I mediatate 50 times, maybe 3 or 4 will be enlightening.
A good clue that you are doing something 'right' is if you can feel your body vibrate. I have heard of masters that can change their vibration frequency and even shift the phase 180 degrees. If you feel the vibrations, try to maintain them, amplify them if you can.
I'm not crazy, it's the voices in my head, they're the ones who is crazy!