ADOT Adaptive Ramp Metering - MILOS

The MILOS adaptive ramp metering system was developed as part of an Arizona Department of Transportation’s (ADOT) Arizona Transportation Research Center (ATRC) research effort in response to the need to develop intelligent strategies to manage congestion in the ADOT freeway system. A key contribution of the MILOS research effort was the development of algorithms that consider ramp queues as well as freeway conditions. MILOS was the first system to consider the ramp queues as an integral part of the adaptive ramp metering strategy. MILOS’ primary objective is to improve freeway flow conditions in a corridor and to recover quickly and smoothly from oversaturated conditions. This project is focused on a field test and evaluation on an I-10 corridor including seven (7) ramp meters. The goals of the project are to demonstrate the effectiveness of MILOS and identify weaknesses and deficiencies that must be address for wide-scale deployment.

Questions? Contact K. Larry Head, Ph.D. at

University of Arizona College of Engineering