On Whether to Allow Computers to Post Traffic Advisory Messages without Operator Approval

Abstract

Traffic Management Centers (TMCs) may control dozens of variable message signs (VMSs). Computers may help TMC operators select messages to post to VMSs, in response to traffic conditions. Errors in posting messages (incorrect location, wording, or both) can complicate traffic management and undermine public confidence in the TMC. An experiment was conducted in the TMC Simulator to compare support systems that directly post messages on VMSs with those that simply suggest messages to the operator. The post condition resulted in better performance in terms of getting appropriate messages posted on the correct signs in a timely fashion. Significant delays were sometimes associated with the operator's response to support system suggestions, even though the suggestions were prompt and accurate. We recommend that VMS management support systems be allowed to post messages without requiring operator approval, given that the messages have been previously approved for content, and the error rate of the support system is acceptably low.