The paper investigates the theoretical influence of field conditions and dynamic characteristics of the vehicles on military convoys' cross-country mobility. Convoys' average traveling speed along hypothetical two-way road segments was assessed by the methodologies described in the Transportation Research Boards Highway Capacity Manual 4th and 7th editions. The assumptions on infrastructure and traffic conditions were as follows. The road segment length varied from 0.4 to 6.4 km, its horizontal alignment was linear, and its vertical grade was larger than 6%. As military convoys have a right-of-way, there were no access points, no no-pass zones, and no vehicles in opposing directions along the road segment, and therefore lane and shoulder widths did not influence convoy speed. Average traveling speed on specific upgrades and downgrades was calculated and compared for convoys with 60%, 70%, and 80% of heavy vehicles. The results show there are significant differences in the speed reduction estimated by different methodologies. The results obtained from the Manual 4th edition methodology show that segment length moderately influences speed along specific upgrades and does not influence the speed along downgrades. The Manual 7th edition methodology results were more sensitive to analyzed segment length, grade, base free-flow speed, and convoy composition. The average traveling speed on specific upgrades and downgrades estimated by the Manual 7th edition methodology is on average 10 to 15 km/h lower, respectively. Therefore, it was concluded that this methodology and its results will be further investigated in local conditions through field research for a more comprehensive assessment of its applicability

modelling; road alignment; platoon; speed; Highway Capacity Manual