The drive is 164 km against 132 km as the crow flies, which is the ordinary shape of a German motorway journey. Booked privately it is a single 1h 51 run with no changes, at a price agreed before you set off.
The fare is fixed when you book, so a closed lane or a slow stretch costs you time and not money — there is no meter and no waiting charge. Pickup is any address in Wiesbaden: a home, a hotel, an office, a venue. Drop-off is the exact address in Cologne, not the nearest station to it. The route crosses from Hessen into Nordrhein-Westfalen; the price covers the whole of it including tolls.
One vehicle the whole way, one price, and a departure time you choose rather than one a timetable chooses for you. Journeys this length are mostly booked the same day or the day before, and the car can be at the door within the hour in normal conditions. Arriving by air instead? Cologne Bonn Airport Transfers covers every destination we serve from the airport.
The two journeys a rail ticket does not include
A train time is measured Hauptbahnhof to Hauptbahnhof, and almost nobody starts or finishes at one. The real Wiesbaden–Cologne journey by rail is usually three journeys: getting to the station with your bags, the train itself, and getting from the far station to the actual address — the last of which is a taxi at the far end, at a metered price, in a city you may not know. Those two legs are where the published time and the published fare both stop being the whole story. A private car removes them by starting and ending at the addresses instead, which is why the comparison is closer than a timetable makes it look.