A particular licensing authority can apply for an exemption order if it considers that requiring all taxis to comply with the accessibility requirements would mean that licensed taxi drivers in the area would transfer from being hackney carriage drivers to private hire vehicle drivers, because the cost of purchasing accessible taxis would make their business unprofitable. The Secretary of State can agree to make an exemption order but, in doing so, can require a certain number of accessible taxis to be available in the area.