Highway authorities are responsible for managing their road networks and for proposing and making all types of Traffic Orders. There is no specific legal requirement for highway authorities proposing to permanently close roads or divert traffic via Traffic Orders to assess the impact on emissions. There are requirements for them to consult, in some circumstances, local businesses, communities and those affected by the changes. There are specific circumstances when referral of Traffic Orders is made to the Secretary of State, for example, in relation to extending experimental Traffic Orders or where the same road has been closed several times for special events. The Government has no authority to review changes made by Traffic Orders which may impact on emissions. Elected authorities, including elected mayors, are not provided with any duties under transport legislation to monitor the impact of emissions in their areas of responsibility.