Instant tents are more or less exactly how their name would describe them, being tents that with one, possibly two steps, can be set up at a rapid pace. Traditional tents have gotten easier to set up over the years, can still be a significant pain, and in an emergency when the weather is blowing in, the last thing you want is to have to fight with directions in the wind, with rain and hail beating you down.
These tents can either be internally air pressure powered, which simply involves pulling a cord and letting it inflated spring into form (not unlike self-inflating rafts), be powered by a rapid compressor, or simply be spring-loaded once they unfold.
Instant tents can actually be quite luxurious, with some models having upwards of three or four small rooms in them, able to easily accommodate upwards of 10 people, while cheaper ones fit for maybe one or two people are also readily available for many camping retailers across the world. These are durable, quality tents that require little to no hassle, providing a safe, warm place to sleep whenever you need it.
Anyone on a long trip should have one of these in their trunk, lest you be stranded in the wilderness with nowhere to sleep.