"[And the brothers] told [Jacob] all the words that Joseph had spoken to them; and when [Jacob] saw the wagons (Hebrew: agalot) which Joseph had sent to transport him the spirit of Jacob their father was revived. And Yisrael 
From this very human perspective, we can better understand the Biblical text, as well as Rashi's commentary.
said, 'it is sufficient [for me]; my son Yosef is still alive. I shall go and see him before I die.'" (Genesis 45:27-28)
Why doesn't the younger Joseph travel up to Israel to see his aged father? And why does Jacob even agree to take the difficult journey to Egyptian exile in order to meet his son? Logic, as well as filial respect, suggests that the younger child make the effort to meet the older parent.
The narrative style of the Bible is extremely terse, utilizing a minimum of words to imply a maximum of emotions and leaving it to the reader to sense the drama - and conflict - which lies between the lines and behind the utterances. Undoubtedly, when first hearing the amazing and mind-boggling news that his beloved Joseph is not only alive, but is also the revered and powerful Grand Vizier of Egypt, old father Jacob must be bowled over with jubilance and gratitude to G-d.
But as the reality of Joseph being alive takes root, many thoughts and emotions must race through the patriarch's mind. How did Joseph get to Egypt in the first place? Did he abandon his Abrahamic homestead and destiny; opting to take to his heels when his father sent him on a mission to check on his unfriendly brothers, embarking instead on his own ambitious journey toward acquiring those very sheaves of grain - products of a more sophisticated but less spiritual Egyptian civilization - which he had dreamed about by night and talked about by day?
It was the brothers who brought Jacob a bloodied cloak of many colors, seemingly the only remains of a son who had been devoured by wild beasts. Was it perhaps Joseph himself who purposefully left the cloak behind, a false clue, yet symbolic of his desire to forsake the family and its tensions in favor of the new lifestyle which he yearned for? Might it even be - Heaven forbid the thought - that the brothers themselves had sold Joseph, their own flesh and blood, into Egyptian slavery, and then covered up their unthinkable deed with the bloodied cloak?
And as the old man pushed aside this latter possibility from his consciousness - confronting his sons with such a deed would only bring about an irreparable break in the fragile family fabric precisely when all of his sons were finally at the brink of coming together - the dismayed frustration implicit in his doubts and questions began to center on Joseph. How could the beloved heir to his family fortune and function act so callously regarding his father? No matter how Joseph had gotten to Egypt, shouldn't he have sent some word via a messenger (if a personal visit had been impossible) to inform his depressed and disconsolate father that he was still alive? He certainly knew how much his father loved him, had doted on him. Jacob's elation may well have turned to disappointed anger pointed at Joseph: 'I am overjoyed that you are alive, but how could you have refrained from contacting me earlier?'
From this very human perspective, we can better understand the Biblical text, as well as Rashi's commentary. Immediately after informing us that the brothers told Father Jacob all that the Grand Vizier had revealed to them, the verse concludes, "And when [Jacob] saw the wagons which Joseph had sent to transport him, the spirit of Jacob their father was revived." (ibid. 45:27) Rashi (ad loc) comments that the wagons (agalot) were a sign that Joseph sent to his father, reminding him that the last Biblical portion they had studied together was that of the beheaded heifer (the Hebrew for heifer is egel, a play on agalot, or "wagons", which were usually "heifer-drawn.")
The connection, however, is much deeper than linguistic. The Bible (Deuteronomy 21:1-9) ordains that if a corpse murdered by an unknown assailant is discovered between two cities, the elders of the nearest city must bring a heifer sacrifice, declaring that "our hands did not shed this blood," followed by a request for atonement. Clearly the elders themselves did not commit the heinous crime of murder. Nonetheless, responsibility falls on their shoulders because apparently they had not been sufficiently sensitive to the welfare needs of their citizenry; they had neglected to supply the requisite social services for the poor, the addicted and the unstable in their city. Greater sensitivity and involvement would no doubt have prevented the tragedy just outside their city boundaries.
Joseph was gently reminding his father that he, Jacob - the "elder" of the family and of the nascent nation - should have been more sensitive to the tragedy that could arise from a father's blatant favoritism of one child above all others (Babylonian Talmud, Shabbat 10b). Joseph may be hinting to his father that on some level he still harbored resentment towards him and, despite his powerful position in Egypt, had never contacted him because (not unlike 
Joseph may be hinting to his father that on some level he still harbored resentment.
the elders in the incident of the beheaded heifer) Joseph saw a direct link between his father's questionable familial management and his 'favorite' son's death sentence in the pit, 'commuted' at the last minute to a life-sentence as a slave in Egypt.
But the beheaded heifer is also a symbol of atonement, of forgiveness. Also built into the "wagons-heifer" (agalot - egel) is Joseph's message to his father that he forgives the elder's insensitivity within the familial context, that Joseph (now a father himself) understands the difficulties and complexities of parenthood, that his father's transgression is especially forgivable because it emanated not from too little love, but from too much love, and that it was also a function of the very special feelings his father had for his beloved, deceased wife Rachel, and therefore for her eldest son.
Most of all, Joseph forgives his father because he has learned from his elder brother Judah the importance of taking responsibility. Judah will do whatever needs to be done in order to discharge his responsibility to see to it that Benjamin will return safely to Jacob, even if it means that he, Judah, will become the slave. From this perspective, Joseph realizes that he acted arrogantly towards his brothers, that he only exacerbated their jealousy and hatred by telling them his supercilious dreams; that despite his father's inelegant and almost vulgar favoritism, he himself - in the final analysis - must take full responsibility for their hatred and having been sold as a slave. Indeed, maturity begins when we stop blaming our parents, our teachers, our friends, and take only ourselves to task for whatever shortcomings we might have (as my own son Hillel always says).
And so, when Jacob saw the wagons his spirit was revived. He understood the message. He accepted the responsibility for his son's resentment and fully understood why he had not contacted him earlier. "It is enough that my son is alive," he says, and I shall no longer waste time apportioning blame and standing on ceremony as to who should go to whom first. After all, no parent can divorce himself from his child, and no child can divorce himself from his parent or even from his siblings. With the exception of the most abnormal circumstances, a child who severs relationships with a parent is cutting himself off from his essential essence, and a parent who severs relationship with a child is cutting himself off from his existential future. Parents, children and siblings are inextricably bound together. This is what Jacob and Joseph both learn from this magnificent Biblical epic.
Since in the normal course of events the father's death precedes the son's, it makes sense that it is Jacob who will make the initial move, so that he and Joseph may finally embrace each other - before Jacob's death.