**Alcohol** significantly affects a driver's behavior. When a person consumes alcohol, they may experience a **false sense of security** and expose themselves to more risks. This can lead the driver to treat other drivers more **aggressively or impulsively**, increasing the likelihood of accidents.

Alcohol also affects **decision-making**, causing the driver to need more time to react and increasing the likelihood of making poor decisions. However, the most notable characteristic in behavior is the tendency towards impulsive and aggressive responses, which confirms that the correct answer is that alcohol causes **impulsive and aggressive responses towards other drivers**.