One of the primary traveler information applications of interest throughout the Corridor is posting travel time on signs. With the successful launch of the I95 Vehicle Probe Project (I95VPP), increased attention has been given to this application, with several inquiries for guidelines to appropriately use the I95VPP data to post quality traveler information on changeable message signs. This application presents technical challenges of understanding the quality, data lag issues, and inherent predictability of travel time in order to create quality traveler information. As opposed to 511 and web services, the real-time requirements for quality information (and resulting negative feedback if such information is not accurate) put extra scrutiny on such applications.

Posting travel times on changeable message signs (CMS) is a traveler information service of growing interest throughout the I-95 Corridor. With the success of the I-95 Vehicle Probe Project (I-95VPP) many states now have an affordable and accurate data source to drive this application. As a result, several inquiries for guidance on the use of I-95VPP data for this purpose have been made to the Coalition. Travel time on changeable message signs (TTCMS) requires higher quality and more immediate real-time data than many other traveler information services, due to its high visibility and direct impact on driver behavior. In addition to data quality concerns, consistent and effective program and message display policies have proven critical for successful deployments.

Procurement Agency: FLDOT and New Jersey Transit
Project Contact: Glen Glotzbach and Sandra Check

The objective of this project is to create a guide for the use of the I95 Vehicle Probe data as a source of posting travel times on signs, and recommended messaging to maintain consistency throughout the corridor. The guide will review existing practice within the Corridor for posting travel time information on Changeable Message Signs (CMS). Technical aspects such as best practices for smoothing, filtering, and aggregating sensor data will be addressed as well as policy aspects such as segment lengths, message content, and frequency of update. Case studies and lessons learned will be drawn from available applications within the Corridor regardless of data source.

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Deliverables: Vehicle Probe Project, Guide for Posting Travel Times on Changeable Message Signs, October 2011

Posting travel time on changeable message signs (CMS) arguably has greater potential to influence driver behavior than other conduits of traveler information. Travel time on CMS provides the most current, detailed, and route specific reporting of traffic conditions directly applicable to drivers, in the safest, most easily accessible form. For these reasons, travel time on CMS is arguably the most effective method to inform and impact driver behavior.

The resulting guide was assembled to provide recommendations for the appropriate use of the I-95VPP data as the source of posting travel times on signs and to provide recommendations for program policies related to the display of travel time messages. This guide reviews existing practice within the I-95 Corridor, explores technical best practices for aggregating, smoothing, and filtering sensor data, and overviews policy considerations for items such as segment length, message priority and content, and frequency of update. Case studies and lessons learned are drawn from states with existing TTCMS programs.

In addition to the technical and programmatic guidance, the project helped to identity implementation issues that have not converged to standard practice. As the I95 VPP continues to expand in geographic coverage and in use for delivering travel time on signs, such issues will need to be revisited as more is learned. This guidebook completed in 2011 serves as the basis for prevailing art and practice in this area on the Eastern Seaboard. It is recommended that minor updates be initiated as application issues are identified and practice evolves.

Final Project Expenditures: $31,500