Does the Prius Two have an emergency brake?

yes, to the left of the foot brake. i think it is required by law on all vehicles.

 

sorry! see my edit.

 

absolutely. in fact, toyota recommends it. push down to lock, and push down again to release. i prefer to step on the parking brake, then let off the regular brake to make sure it's tight enough, then put it in park.

 

exactly.

 

Yes ... it really is a parking brake, to keep the car stopped when it is stopped. They try to make the regular brakes redundant enough that you probably won't ever need to use it as an "emergency" brake to stop the car (this is pretty much true of all modern cars). If you ever do need to use it for stopping, be careful:

• It won't stop the car quickly at all: it acts only on the back wheels, and has only a cable linkage without any of the hydraulics and power assist of the regular brakes.
  
• A braking car shifts its weight off the back wheels, putting a real limit on how quickly you can brake without simply skidding the back wheels.

If those points are true of pretty much all cars, there's an extra point about this parking brake to take note of: it is a push-on/push-off style. That means if you actually use it in an emergency, and you get excited and stomp too hard and skid the rear wheels, you won't be able to just let your foot up to end the skid. You'll have to remember to push-to-release.

The best approach for using it to slow the car (you can practice this in some non-emergency settings until it doesn't feel weird) is to start with a quick double-push so the push-to-release is already released; then you can control it by pressing more or less hard, just like the normal brake (... as long as you don't let it all the way up, then press again, which would engage the ratchet again).

-Chap