How tall children must be to rindde alone?

The website tells you this.

Ride What??

42 inches. My daughter is almost 5 and was just barely tall enough to ride alone.

I got this from their website. "All children under 42 inches tall must ride on an adult's lap, with only one child per lap. Both children and accompanying parents must have a ticket."

I am not sure how tall but the seats are very high, I wouldn't recommend a 4 year old to ride alone