Phoenix a few years ago started Medical Response units to assist stations that are running more then 3500 calls per day. Firehouse 18 has Engine 18 and Engine 918 and they both are running more then 3500 calls each so the decision was made to put Low Acuity 18 in service which was a BLS unit which quickly became Medical Response 18 which is ALS. Medical Response units are over-time companies that run 12 hour shifts to assist with taking a hit on the call volume. The new Medical Response units are 2021 Ford F550 / Rosenbauer units.

Medical Response 3 came about very quickly to assist Firehouse 3 with the homeless zone. This is rougly a half mile area that they run to continuously. The runs are mostly medical around the homeless tents and shelters.

Medical Response 154 is a Phoenix unit that is housed at Glendale Firehouse 154 to assist with the amount of calls Engine 154 runs into Phoenix.