What about when you're having to backtrack on a runway...? Tell us that you'll never exceed 20kts and not ever expedite because your SOP says that 20kts is max, eh?
Taxi speeds refer to taxiways. Thankfully on runways we are certified for higher speeds or else it would mean very big wings.
For those of you who like to make up the 20 seconds or so by taxiing fast remember your ops monitoring is watching you. If the CCM above that claims she got bruises were to take a case ( and a bruise ) which matched a taxi speed exceedance of yours it would mean you paying the legal bills. Even if someone else takes a wrong turn or ATC change your clearance late it would be still your fault.