http://www.army-technology.com/projects/challenger2
"The maximum speed by road is 59km/h and 40km/h cross country"
59 / 3 = 19.66666666666667 = 20 rounded up...same procedure for any vehicle
so by that source it's slow by one........ not something likely to stand out in game play but I will confirm that info and make the change if it's justified.
http://www.military-today.com/tanks/challenger_2.htm
Maximum road speed | 56 km/h |
56/3= 18.66666666666667 = 19 which is what's in the game now so I guess it depends on the source