What is the difference between a letter of support (LOS) and a letter of intent (LOI)?

A letter of support (LOS) provided by ADOT indicates that ADOT is recommending the project for funding and does not constitute ADOT's agreement to administer the project. A letter of intent (LOI) is sent to ADOT by a local entity and requests ADOT to administer a project if the grant is awarded with necessary commitments including financial responsibilities and future IGA/JPA. The LOI is countersigned by ADOT to indicate it agrees to administer the project.