Not exactly. A trolleybuss will not run at 90km/h.
My city got a significant trolleybus network. It's on slow streets only because that's where public transit stops are. But from technical perspective, there's nothing stopping from putting them on a highway. The biggest issue is tight intersections downtown. They go painfully slow at those. Straight line? No problem at all and they can safely floor it. And boy is there a difference between flooring a trolley and a diesel bus...