Historic Downtown Preservation and Access Act This bill amends the Internal Revenue Code to allow refundable tax credits for 50% of the expenses paid or incurred by the taxpayer during the year for: (1) installing an elevator or a sprinkler system in a certified historic structure, and (2) hazardous substance (lead paint, radon, and asbestos) abatement services with respect to a certified historic structure. The amount of each of the two credits, with respect to any taxpayer, may not exceed $50,000 per year.