What happened to Willy after he got a little above Yonkers?

Willy stopped for a cup of coffee a little above Yonkers, a suburban city which is only about two miles north of Manhattan. Willy's territory is all of New England, so he was just barely getting started on his customary sales trip. He tells his wife Linda:

I suddenly couldn't drive any more. The car kept going off onto the shoulder, y'know?

The fact that Willy is driving dangerously foreshadows his death in a faked auto accident so his son Biff could collect his father's life insurance. Willy's whole problem is that he is getting old. He shouldn't be driving at all anymore, much less driving all over the states that make up New England, where there are narrow roads, steep mountains, frequent bad weather conditions, and not a whole lot of money. Willy's exact age is not specified, only that he is "past sixty years of age." 

This incident above Yonkers will have tragic consequences. Willy will decide to ask to be transferred to a territory closer to home. His young boss will refuse, saying that Willy is the company's "New England man," which suggests that Willy has the near-impossible task of covering all of New England by himself. There isn't enough business in those then-thinly-populated states of Maine, Vermont, New Hampshire, Massachusetts, Connecticut and Rhode Island to make it worthwhile to divide up the territory. The interview with Willy's boss turns into a heated argument, and Willy ends up getting fired after devoting so many years of his life to this one company.

Where does a man in his sixties go to find another job? Nowhere. This is the essence of Arthur Miller's message. Capitalism uses up men's lives while they have youth, ambition, confidence, and energy; and then it casts them out in the cold. Willy's death by apparent suicide seems inevitable from the very opening of the play. 

The title Death of a Salesman does not strictly apply to Willy Loman. The term comes up when Willy is talking to his boss Howard, trying to get transferred to a territory closer to home. Willy reminisces about a salesman named Dave Singleman, whom he knew years ago. Singleman was eighty-four, but he was still active as a traveling salesman. Willy got the mistaken idea from this old man that he could make money for himself no matter how old he grew. His idea was that a salesmen could accumulate so many friends on his route that their business would practically fall into his lap. But Singleman was a "single" instance. Willy is washed up in his sixties. Nobody comes to his funeral except for his family and a neighbor.

He describes Singleman's death and funeral as if the old man were a hero.

Do you know? when he died--and by the way he died the death of a salesman, in his green velvet slippers in the smoker of the New York, New Haven and Hartford, going into Boston--when he died, hundreds of salesmen and buyers were at his funeral.