Streamlining and Investing in Broadband Infrastructure Act This bill requires the National Telecommunications and Information Administration to issue best practices relating to broadband infrastructure and installation for state broadband coordination offices, with an emphasis on rural areas. The Department of Transportation (DOT) must require states to install broadband conduits, which support broadband or wireless facilities for broadband service, in certain highway construction projects. DOT must ensure that: (1) standards are established that apply to all areas, including rural and remote areas with low population density; and (2) any requesting broadband provider has access to such installed conduits on a competitively neutral and nondiscriminatory basis, for a charge not to exceed a cost-based rate. The bill amends the Middle Class Tax Relief and Job Creation Act of 2012 to require federal agencies and other entities to grant real property interests necessary for the installation, construction, or modification of a communications facility installation, as defined by this bill.