to identify and address blocked crossings. (2) How current and future technology could be used to identify and address instances of blocked crossings, including the data collected by each rail carrier’s positive train control (PTC) system. (3) How to identify and address instances of blocked crossings at crossings with only passive or no warning devices. (4) Whether rail carriers should be required to address credible reports, as defined in section 234.5 of title 49, Code of Federal Regulations, of blocked crossings. (5) How best to use the data collected under the web page established by the Secretary for the public and law enforcement to report instances of blocked crossings, including whether such data should be verified by each rail carrier or incorporated into the National Crossing Inventory. (d) Authority To implement regulations If the Secretary finds in the report required under subsection (a) additional regulatory changes that are warranted to alleviate or reduce the instances or impacts of blocked crossings, the Secretary may promulgate rulemakings to implement such changes. (e) Limit on Secretary authority Nothing in this section shall be interpreted as allowing the Secretary or a railroad to not comply with— (1) section 21103 or a regulation issued pursuant to such section