Remedial Education Improvement Act This bill requires the Department of Education (ED) to award grants to improve remedial education programs at institutions of higher education (IHEs). ED must contract with an independent evaluator, who shall (1) consult with ED regarding which eligible entities should receive such grants, and (2) evaluate the impact of remedial education programs funded with such grants. A recipient must use grant funds to develop or improve a remedial education program through specified models, such as (1) aligning coursework between high school coursework and postsecondary education, (2) accelerating course work (e.g., by allowing multiple sequential remedial course enrollments in a semester), or (3) specifically targeting skills that students need to move forward in courses at the postsecondary level. ED must give preference to recipients that primarily serve low-income students, and it must ensure that (1) at least 30 eligible entities are awarded grants in a 5-year period, (2) grants are geographically distributed in an equitable manner, and (3) grants are used to develop or improve remedial education programs under specified models and for a range of types and sizes of IHEs.