What is Night time like in Ancient Rome?

One of the great fears in Rome (the city) was fire, and any light or lantern would be a threat, so the roads were unlit. There might be some light from houses and businesses but they would be extinguished at the end of the day.

Groups of former slaves, the vigiles, were employed to patrol the city, their job was firefighting (and prevention of crime), they carried out their job by creating firebreaks if a fire did occur.

Travelling was risky in the city, the night hours were the only time that wagons were allowed within the city walls and with unlit roads collision was a possibility. The wagons were bringing in supplies for the businesses in Rome and taking out the detritus.

Night also allowed the criminal elements free roaming, so you should not be out alone. Since carrying edged weapons (like swords) was nominally illegal in the city, taking slaves armed with cudgels was a sensible precaution.

But there were entertainments in the city – theatres, brothels, bars, eateries, baths, barbers offered their services.

Lots of traffic. The city had a regulation on carts and wagons in the city during the daytime, due to congestion. Most hauling transport was done at night or very early morning. And there weren’t much if any torch-lighting along the avenues so you’d need your own, and hopefully some kind of weapon too since brigands thrived in the cover of night.

Not really, Rome was a dangerous place at night.