I'm sure it has gears for high and low speeds and maybe even incline. If you have four adults pedaling then you're bound to get up enough power and speed that movement should not be a problem.
I told LDS_forever that I can put side panels and a wind breaker so everything should remain intact on her outfit / self .
I also like how they added the little seats in the front for kids, but they will need some kind of seat belt or restraint for sure. Any kid would have a blast on this.
I am not sure I want seat belts on the front. If the child gets on your nerves you can ditch them by hitting the brakes hard.
Ok I am kidding. I believe that some type of restraint can be placed so the children in the front are well protected from any injury.
I will have to look at the gear ratios. Even with more than one adult pedaling if you have a nice gear ratio you can perhaps reach highway speeds.
With four adults should be Ok and yes I think children would have a blast in the reversed rumble seat.
With out complicated suspension nothing is safe with four men in it . Nice thing the kids get out of line you can poke them with a nice sharp stick.