A night-time expansion is coming to Cities: Skylines on September 24, publisher Paradox Interactive has announced.

After Dark is the hit city builder’s first expansion, and will include a day-and-night cycle, new night-time city services and options, and more.

It will be available to players of Cities: Skylines for US$15.

As per Paradox:

In After Dark, the sun will set on mayor-players’ in-game cities – but it will rise once night-time is over, so nobody needs to worry. Towns will look – and behave – differently at night, with new leisure-focused nightspots, popular beachfront properties that thrive during the daytime and new systems such as taxicabs, prisons, bike lanes and much more.
Cities: Skylines gets crime-ridden After Dark expansion

During the night, citizens go out less and prefer to stay indoors, there are not as many private vehicles on the roads opening things up for service vehicles, and crime increases.

A separate night-time budget will allow players to schedule service vehicles, adjust police numbers, and more.

“Taking the cities from daytime to night is not as simple as one might think,” said lead designer Karoliina Korppoo.

“While the change from day to night is visually stunning, there's much more going on under the hood. Each and every building in the game received a new texture layer to have the windows light up nicely.

“In addition there are new lighted signs, neon signs and other lights to make the city look interesting during the night. The sun rises and sets, painting the sky with bright colours, you can see the moon and stars move across the night sky."

You can read more about the construction of After Dark on the game’s official blog.