My landlord will not plow the parking lot...?

Does anyone know if my landlord is required to plow the parking lot when it snows? I live in CO, and it just snowed about 2 feet this past couple of days, and I haven't been able to get out of the parking lot to go to work. I looked outside last night, and my landlord actually plowed alittle bit, but he plowed all the snow behind my car. So I still was not able to get out. My landlord sucks at fixing things and doing what he is supposed to do. But he only does a certain amount so that he doesn't get into trouble with the laws of CO. What are my rights as a tenant towards being able to get in and out of the parking lot without hitting someone else's car? Please help!!!