Yes they are, but that does not make the centrifugal forces cancel out. Those are speeds as would be measured by a speedometer placed on the truck, and on the edge of the carousel. If the carousel's diameter is much smaller than the truck's race track diameter, then in order for the centrifugal forces to cancel out as you seem to think, the speeds would have to be vastly different, not the same. Consider driving a car at a speed of 30 around a small circle, versus driving a car at a speed of 30 around a larger circle. Which one makes you feel more of an attraction to the side of the vehicle?