Nothing delays getting on the road more than condensation on your windshield. Well, maybe ice, but that’s another story.
Dangerous driving in winter mornings can also often be contributed to impatient drivers beginning their commute before fully defogging all windows. Being in a hurry to get on the road doesn’t allow enough time for the car to heat up fully, and clear away the fog.
Outside it's cold and dry due to lack of humidity and inside the car is naturally warmer. Sometimes foggy windows can be contributed to the opposite effect. If your car is cold, but the air is humid, you could get condensation on the outside of the car. If this happens, you can use your air conditioner to help adjust the inside temperature and remove the fog.
Foggy windows usually happen during the winter when the temperature and moisture are different between the inside and outside of the vehicle. If you can get the temperatures closer together, the fog will disappear. Ideally, if you wait until your engine has heated up, you can then blow warm air on the windshield with defrost, which will evaporate the moisture.
If you need to defog the windows right away, the fastest method is to lower the inside temperature to stop condensation on the glass. Try turning on the defrost vent without heat to dissipate the fog on the window. This is best done when you really are in a hurry to get moving, as it is hard to withstand cold air blowing in the car.