What the driver experienced is what we normally call an "adrelanine rush" this is caused by the Epinephrine neurotransmitter. This is a neurotransmitter that is released through the body in a time of stress. It is produced in the adrenal glands, the brainstem and the brain. They circulate through the blood and then execreted through urine. What the driver went through it's called a fight or flight response.