Appendices : evaluation of variable speed limits on I-270/I-255 in St. Louis.

In May of 2008, the Missouri Department of Transportation installed a “Variable Speed Limit” (VSL) system along the I-270/I-255 corridor in St. Louis. This project evaluated the VSL system and its potential impacts and benefits to the transportation users. The technical system evaluation focused on three areas - mobility, safety, and public and police perceptions. The VSL is not performing as desired in terms of improvements to overall mobility along the corridor, but is providing limited benefits to some segments. Noticeable benefits have been seen with respect to reduction in the number of crashes during the evaluation period. The driving public and law enforcement are widely dissatisfied with the VSL system based on their perceptions of benefits to congestion relief, compliance with posted speed limits, and overall visibility of the current sign configuration. This document contains the following appendices to the final report: (A) Methodology; (B) Process Data and Assessment; (C) Literature Review; (D) References; and (E) Data Collected.