Rural Reasonable and Comparable Wireless Access Act of 2018 This bill directs the Federal Communications Commission (FCC) to commence a rulemaking to establish a national standard for determining whether mobile broadband service in rural areas is reasonably comparable to the service provided in urban areas. The FCC shall gather data about the average signal strength and speed of mobile broadband service from the 20 most-populated urban areas. The service provided in rural areas shall be deemed reasonably comparable to urban areas if the average signal strength and speed meet or exceed the averages in the most-populated areas.