What quotes from Crime and Punishment support the recurring motif of bridges and crossroads?
You've chosen a very interesting motif, and you're right, there are many examples throughout the novel of this motif. In fact, we have a bridge appear in the very first sentence of the novel:
"On an exceptionally hot evening early in July a young man came out of the garret in which he lodged in S. Place and walked slowly, as though in hesitation, towards K. bridge."
Raskolnikov is thinking about attempting something but with hesitation. So the question is, will he "cross this bridge," will he attempt what he is thinking about?
Later on, he does indeed cross the bridge, and gets a sense of relief, of freedom, from doing so:
"Crossing the bridge, he gazed quietly and calmly at the Neva, at the glowing red sun setting in the glowing sky...Freedom, freedom! He was free from that spell, that sorcery, that obsession!"
An interesting quote that discusses R.'s relationship with roads describes how he often wanders down roads without knowing where he is going, so the roads in this case could symbolize his general state of confusion and uncertainty. Dostoevsky writes,
"It had happened to him many times going home
not to notice the road by which he was going, and he was accustomed to walk like that."
In another passage, R. is not at a crossroads persay, but is in a doorway/gateway and is hesitating. R. often hesitates at crucial points, and at roads, doors, and bridges:
"He stood hesitating in the gateway. To go into the street, to go a
walk for appearance' sake was revolting; to go back to his room, even more revolting."
At one point, R. has a dream, and in that dream there is a road leading to a graveyard:
"Near the tavern the road became a dusty track, the dust
of which was always black. It was a winding road, and about a hundred paces further on, it turned to the right to the graveyard."
When he awakes from the dream, he asks himself if he is really going to commit the murder, so the road in the dream could represent a pathway to death.
Here are two more quotes discussing a bridge:
"This reminded him of the bridge over the Little Neva and he felt cold again as he had when standing there. 'I never have liked water,' he thought, 'even in a landscape...'"
And then a short while later, R. thinks,
"'In another week, another month I shall be driven in a prison van over this bridge, how shall I look at the canal then?'"
In these quotes, R. contemplates the bridge and the water underneath, and he doesn't have a good feeling about the bridge or where it is leading.
There is a quote mentioning a crossroads in addition to the one you mentioned:
"They had just reached the cross-roads. The man turned to the left without looking behind him. Raskolnikov remained standing, gazing after him."
The man who accuses R. as being the murderer goes one way and R. just stands there, once again stuck at a crossroads.
Later on in the book, R. is trying to convince Sonia to take a certain "road" or "path" with him: "So we must go together on the same road!"
There is yet another mention of crossroads, by Sonia, who says to R.,
"'Go at once, this very minute, stand at the cross-roads, bow down, first kiss the earth which you have defiled and then bow down to all the world and say to all men aloud, 'I am a murderer!' Then God will send you life again. Will you go, will you go?'"
Sonia sees the crossroads as an opportunity for R. to redeem himself and confess.
There are certainly other mentions of bridges and roads in the novel, but hopefully these are enough to get you started on your essay. And of course you can write a much more detailed analysis of how you interpret the quotes.