Two wheels in front or even 4 wheels doesn't magically make things safer (4 wheel ATV's are still plenty dangerous).
In the US, a lot of the reason for putting 2 wheels of 3 in front is that you get classified differently as a vehicle than if you had 2 wheels of 3 in the back.
>Two wheels in front or even 4 wheels doesn't magically make things safer (4 wheel ATV's are still plenty dangerous).
It isn't magic, it's physics. See this post for a breakdown of the two configurations. [0] The Twike uses the delta configuration, which is know to have issues.
In the US, a lot of the reason for putting 2 wheels of 3 in front is that you get classified differently as a vehicle than if you had 2 wheels of 3 in the back.