Can I control the rate at which new prisoners arrive?

I don't want to be flooded and descend into chaos. I want to build a prison that lasts.

Solution 1:

Currently, the alpha version will continually send you new prisoners each and every day. It's meant to ratchet up the pressure each and every day, dealing with your new inmates.

That said, you CAN avoid gaining new prisoners by removing your delivery area next to the road. Just click the Rooms button, and use right click to remove the delivery designation. You still need a delivery area, though, so move it further away from the road. The game logic has no idea where to put the prisoners, so they don't get off the truck, and just continue on. The To-Do List will still show you how many prisoners will get sent the next day, and they'll keep trying. But without that delivery area, they just keep going.

That should allow you to stabilize your current bunch of prisoners without gathering new problems. Once you're ready for new prisoners, just put the delivery area back!

Fun note: your guards will still attempt to escort your "new" prisoners to the holding cell, even when they're on the truck. I had a couple guards chasing the truck until it left the area, so hopefully riots and whatnot are not brewing prior to getting your delivery.

In Alpha 2, as noted by @Crowbeak, any new prisons you create have an option to only send prisoners when you have room for them. For anyone using a save game from Alpha 1, though, this trick still works.

Another thing to note, though, is that your holding cell now counts for how many prisoners you can hold. I believe for every six squares your holding cell has, your prisoner space is increased by one, in addition to whatever cells you have created. So if you have the new option set, keep that in mind.

Solution 2:

As of Alpha 2, there is an option when creating a new prison to have new prisoners sent only when there are cells for them.