The loading on school buses is determined by the relevant sections of the Road Traffic Regulations (Construction. Equipment and Use of Vehicles). A maximum loading is calculated on the basis of three schoolchildren to every two adult seats. There is no extra allowance for standing passengers.
The position therefore is that a 45 adult seater bus can carry 67 schoolchildren, a 49 adult seater bus 73 schoolchildren, etc. Bus Éireann, which operates the scheme on behalf of my Department, ensures that the loadings do not exceed the maximum legal carrying capacity of the different bus types in use.