I think if the vehicle is only able to drive 25 mph it is not allowed to drive on the freeway, otherwise one would need to allow tractors by the same argument.<p>In most European countries there is a minimum speed requirement when driving on thr motorway (usually between 60 - 80 km&#x2F;h), and sometimes there are even lane-specific speed limits (e.g. left lane requires at least 110 km&#x2F;h). All that is only relevant if the traffic actually allows you to go that fast of course.