Next sentence, eight streets, nine streets.

In Han Dynasty, Chang 'an City had convenient transportation, wide streets and straight and square roads, just like latitude and longitude.

Eight streets and nine streets are bustling, which means that eight streets and nine streets describe the streets and bustling markets of the city. From "Old Stories of Three Ancient People": "In Chang 'an City, there are eight streets and nine strange streets." In Han Dynasty, Chang 'an City had convenient transportation, wide streets and straight and square roads, just like latitude and longitude. Every street from the city gate to the urban area is "paved with three wide roads", and 12 cars can be parallel at the same time. According to various documents, Chang 'an City in Han Dynasty had eight streets and nine lanes. It is used here to describe that the streets are very busy and bustling everywhere. Describe a sea of people. Describe how many people gathered.