The objective of the present work was to study space allowance in cattle during commercial long haul transport (≥400 km; n = 6,152 journeys). Surveys, delivered to livestock transport carriers, gathered information on the number, BW, and distribution of cattle by trailer compartment as well as the characteristics of the transport vehicles used. Space allowance (SA; m(2)/animal), allometric coefficient (k = SA / BW(0.6667)), and the percentage of deviation from recommended SA (DRSA; %) in the Canadian Codes of Practice were calculated for each compartment of the trailers. All quad-axle (77%) and tri-axle (23%) cattle trailers were reported with 5 compartments (nose, deck, belly, back, and doghouse). Sixty percent of all animals were carried in the middle compartments (deck and belly), 30% in the rear (back and doghouse), and 10% in the front or nose. Approximately 30% of the journeys required that the cattle be redistributed at the Canada-USA border to comply with different axle weight regulations, and most journeys moved them between the deck and the doghouse. Total loaded weight increased and the number of animals decreased with increasing BW of the animals. space allowance, k-value, and DRSA were least for calves and feeders compared with fat and cull cattle (p < 0.01). Both total loaded weight and number of animals increased with the number of axles in the trailer, being greatest in quad-axle trailers pulled by push tractors, which were most frequently used. Space allowance (k-value) was least in vehicles with greater number of axles and transporting the lightest cattle (i.e., quad-axles trailers transporting calves and feeders). Space allowance, k-value, and variability among journeys were least in the middle compartments (belly and deck), followed by the back, then doghouse and nose compartments of the trailers showing the largest values (p < 0.05). Many factors contributed to the variability in SA such as body size (smaller animals are placed more densely), compartment of the trailer (greater density in belly and deck), and number of axles on the vehicle (greater density with more axles). The present study provides a framework to assess and understand factors affecting SA during commercial long distance transport of cattle. This information is vital in assessing the consequences of changing industry standards, guidelines, recommended values, laws and regulations on animal welfare, the industry, and economics.