Не могу разобраться с конструкторами ООП. Почему они не работают?

<script type='text/javascript'>

function Automobile(color, model, year, manufact)
{
	this.color = color + " " || "white";
	this.model = model + " "|| "A1";
	this.year = year + " "  || "2000";
	this.manufact = manufact + " " || "Toyota";

    function autoInfo () 
	{document.write(this.manufact + this.model + this.year);}

    function autoColor()
	{document.write(color);}
}

function driver (color, model, year, manufact, name, experiance)
{
	this.base = Automobile;
	this.base(color, model, year, manufact);

	this.name = name  + " " || "Vasiliy";
	this.experiance = experiance + " " || 1;

    function driverinfo()
	{document.write(this.name + ": experiance " + this.xperiance + "year");}
}

vlad = new driver ("Red", "Skylane", "Nissan", "Vladislav", 5);
    vlad.autoInfo();
    vlad.autoColor();
    document.write("<br/>");
    vlad.driverinfo();

</script>