Level Up (A5E) New DM for A5E has some questions.

[Keto]

Hello there.
I am soon going to become a DM for A5E. I have been reading the rules and, so far, enjoying what I see. Definitely an improvement upon 5e and most of my players dig the idea. However, I have some questions on several topics while reading this. I will make sure to create a different thread once I come up with more questions, but so far these few will suffice.

1. If you have a 1d4 expertise die in a skill (e.g. Acrobatics) and another 1d4 expertise die in a skill specialty of the same skill (e.g. Tumble) do these two mix into a 1d6 once the player makes an Acrobatic check that applies usage of Tumble specialty? So if I have 1d4 expertise die on Acrobatics and no die on Tumble, do I still get 1d4 expertise bonus on tumbling because the Tumble is like a 'sub-skill' of Acrobatics? Just curious how these interact. If you can use any helpful examples, please do.

2. If I used 'Brake' with my vehicle on this turn it would move half its movement speed and lose momentum. Next turn I could use 'Stop' to make it halt since it has no momentum. However, what if I do nothing? Like, what if I do not use a 'Stop' action and do not keep driving it? Will it just stop by itself without me using any bonus actions to command it to do so?

3. If, for example, a gargantuan vehicle hits a halfling... will both the vehicle and the halfling take 12d6 bludgeoning damage? I know that the halfling will be shoved out of the way because they're Small, but considering their size and mass... will the vehicle really be taking that much damage or am I missing something?

I will have more questions as I progress, but this is it for now. I appreciate any constructive answers.
Really fell in love with this system so I hope I can have a great time with the community and too.

 

[Stalker0]

So for number 1.

1) you get a d4 for all acrobatics checks
2) if it’s a tumble check, it’s a d6 (two expertise dice = d6

 

[Selganor]

Only vehicles with momentum move on their own (at initiative count 20) so if you are doing nothing it won't move on your turn hence it would stop on its own.
RAW one character may use a bonus action to "brake" then spend the rest of their turn to do something else (even leaving the "driver's seat") and another character may use their bonus action to "stop" the vehicle on their turn.

As for the collision: There is a note on damaging Huge and Gargantuan objects:

"HUGE AND GARGANTUAN OBJECTS
Against Huge or Gargantuan objects, normal weapons or tools are of little effect. Against a castle wall or treasure vault door, a hammer or word won’t get the job done —but determined creatures might try just the same."

And since the body of an average halfling probably won't do as much damage as a weapon or tool you won't have to worry about halflings you run over to damage your vehicle.

 

[lichmaster]

2. If I used 'Brake' with my vehicle on this turn it would move half its movement speed and lose momentum. Next turn I could use 'Stop' to make it halt since it has no momentum. However, what if I do nothing? Like, what if I do not use a 'Stop' action and do not keep driving it? Will it just stop by itself without me using any bonus actions to command it to do so?

One clarification that could help:

• with brake the vehicle moves half speed forward and then loses momentum
• with stop the vehicle stops immediately, but you cannot use it if the vehicle has momentum

So if the vehicle you're driving doesn't have momentum there's little reason to use brake instead of stop (unless you really want that half movement). If instead the vehicle has momentum, brake is your only option, but it's not equivalent to stop since you MUST move half speed forward, which could be an issue if there's an obstacle or a chasm right in front of you.

So in the end both actions allow you to halt your movement, but one halts you on the spot while the other forces you to move forward half speed first