Are the words in bold correctly used?

[Tan Elaine]

On the day of the speech there were massive protests and demonstrations all over Cambridge from that morning. The protesters and demonstrators had come from London led by London School of Economics students. The very narrow roads of Cambridge were a chock-a-block and the lecture hall was surrounded by them.

Are the words in bold correctly used?

Thanks in advance.

 

[Barb_D]

On the day is okay.
Starting in the morning instead of from that morning.

 

[jlinger]

Drop the article, "a", from this:
The very narrow roads of Cambridge were a chock-a-block ....

Chock-a-block is an adjective. And properly all one word (chockablock).