The front impact pulse used to test child restraint systems in United Nations (UN) regulations has not been updated since it was introduced in the 1980s. However, vehicle tests established later have led to stiffer structures with greater passenger compartment deceleration than vehicles from the 1980s. The aims of this study were to derive an experimental sled pulse corridor from European New Car Assessment Programme (Euro NCAP) full-width tests of modern vehicles and to investigate the effect of this pulse, alongside established corridors (UN R129, UN R16, FMVSS 213), on the performance of child restraints. The Euro NCAP sample highlighted that the UN R129 corridor is not representative of modern vehicles. Other regulatory corridors replicate some aspects of a full-width test, but do not offer a good fit overall. A new corridor would be needed to more closely match an average full-width vehicle pulse, in terms of the peak deceleration, time-to-peak, and the pulse duration. The effect of the pulses on child restraint performance depended on the type of child restraint and the dummy size, but the UN R129 corridor tended to generate the lowest measurements. Any new corridor would challenge current child restraints, particularly if the current UN R129 performance limits are maintained.