# Presentation: 328300

## Driver Use of En Route Real-Time Travel Time Information

- Presentation:
- TMC PFS Annual Meeting
- JULY 15, 2008

## Project Description

- Objectives
- Conduct human factors research to establish a basis for effective implementation of real-time travel time information
- Based on findings, develop preliminary guidance for practitioners
- Scope
- Real-time travel time or related information
- Freeway-based CMS displays
- Contractor: Westat
- Principal Investigator: Neil Lerner

## Travel Time CMS Displays in U.S.

**Travel Time CMS Displays in U.S.**

- Usually presented as text
- Travel time by destination or roadway segment

## Foreign Practice

**Foreign Practice**

- Includes other types of display
- Color coding
- Symbolic
- Network view

## Specific Objectives

- Assess impacts of en route real-time travel time/delay/speed information on drivers
- Define the most effective method to provide en route real-time travel time information
- Develop preliminary guidance to practitioners for delivering en route travel time information

## Project Tasks

- Task 1: Kick-off Meeting
- Task 2: Review and Summarize Literature
- Task 3: Prepare Research Work Plan
- Task 4: Conduct Research
- Task 5: Produce Research Report
- Task 6: White Paper
- Task 7: Coordination and Outreach

- DONE

- DNGOING

- DONE

- DONE

## Task 3 - Three Complementary Research Studies

- Study 1: Actual Driver Experience with Real-Time Travel Time Displays
- Driver logs and focus groups
- Study 2: Driver Comprehension and Interpretation of Display Alternatives
- Laboratory w. static displays
- Study 3: Driver Ability to Use Alternative Real-Time Travel Time Displays
- Dynamic (simulated drive-by’s)

## Issues Covered in Studies

|   | 1 |  2 | 3 |
| --- | --- | --- | --- |
| How do drivers use RTTT in decisions? | X | X |   |
| Effects of RTTT on route choice/diversion | X | X | X |
| What triggers a diversion? | X |   | X |
| Behavioral effects of delay information (safety, slowing) | X |   | X |
| Confusion/ambiguity of meaning | X | X | X |
| Type of travel information (time, speed, delay, etc) |   | X | X |
| Usefulness of supplementary information | X | X | X |
| Alternate formats and message construction | X | X | X |
| Amount of information/reading & comprehension time |   |  X | X |
| Destinations – selection of, descriptors | X | X |   |
| Sign location/distance from destination | X | X | X |
| Credibility - degree of, influences on | X | X |   |
| Perceived benefits of RTTT | X |   |   |
| Perceived limits on usefulness of RTTT | X |   |   |
| Driver population, trip characteristics | X  | X | X |

## Study 1:Actual Driver Experience & Decision Making

- Focus groups in 3 metro areas that display real time travel time: Atlanta, Milwaukee, Seattle
- 45 rush hour freeway commuters from suburbs to downtown areas
- Discussed use of travel time, benefits, limitations to usefulness.
- Viewed and discussed variations/alternatives to current formats.
- Participants completed trip logs for 2 weeks
- Described use of real time travel time signs on commutes: effects on route choice, use of other pre-trip and en-route traffic information, benefits of travel time, changes desired, etc.
- Recorded information at completion of every AM or PM commute

## Study 1: Some Preliminary Observations from Focus Groups

- Highly positive response to travel time information, though it rarely influences behavior
- Unsure how often travel times are updated; this limits credibility
- Travel time preferred to average speed or duration of delay
- Road names preferred as destination designators
- Banner text (e.g., travel time to:), exit number, and distance to destination were seen as unnecessary
- Positive reactions to diagrammatic signs with color-coded traffic conditions, but want this supplemented by travel times
- Given typical overhead 3-line text sign, commuters want sign to show travel times to 3 destinations

## Project Schedule

- _Activity_
- Completion of Experiment 2 and 3 Data Collection
- Draft Report
- Final Report

- _Date_
- Summer/Fall  2008
- November 2008
- December 2008

## Background

- Travel time is a key piece of information for motorists
- It is information they desire and use
- It involves route choice and diversion decisions
- Agencies are making this information available in real time
- “Travel time” information may be expressed as travel time, delay, speed, congestion level

## Concerns

- Need better understanding of factors that promote effective driver decisions
- Lack adequate empirical basis, design guidance for effective displays
- Requirements complications
- Related to roadway network
- Related to individual trip characteristics
- Related to driver characteristics, knowledge

## Some RelatedDriver-Centered Design Issues

- Info needed
- Info sought, desired
- Amount of info
- Timing, location
- Comprehension
- Timeliness
- Credibility, trust
- Perceived benefit

- Usability and safety
- Reading time
- Distraction
- Slowing
- Behavioral response
- Diversion likelihood
- Decision effectiveness
- Control of overall diversion rates

## Task 2 Literature Search

- Domestic and foreign practice
- Published research and analysis
- Expert opinion – practitioners & researchers
- Key organizations and committees
- Summary Findings
- Matrix summarizing US practice, by feature
- Broad findings organized by key questions
- Distributed to TMC PFS members last year

## Main Issues for Research Studies

- 1-Current actual driver use of travel time displays
- Driver logs and focus groups
- Data collected (Atlanta, Milwaukee, Seattle)
- Analysis in progress
- 2-Comprehension/interpretation of display alternatives
- Equipment and software completed
- Selected items pending Study 1 results
- 3-Driver ability to use alternative displays

## Study 2: Driver Comprehension and Interpretation ofDisplay Alternatives

- Lab study to compare sign attributes (e.g., type of destination specification, number of destinations, indication of time uncertainty, single phase vs. multiphase)

## Study 2: Method

- Participants receive instructions regarding their “trip purpose” and view a video segment of a highway drive.
- Participants view various travel time displays, then answer questions about message content, likelihood of diverting, etc. Response times are recorded.
- Data collection followed by group discussion

## Study 3 Driver Ability to Use Alternative Real-Time Travel Time Displays

- Speed of simulated drive is under participant’s control – “accelerator pedal”
- Provides data on driver decision to divert or maintain present route
- Provides relative measure of vehicle slowing for different signs

## Study 3: Driver Ability to Use Alternative Real-TimeTravel Time Displays

**Study 3: Driver Ability to Use Alternative Real-Time****Travel Time Displays**

- Lab study - Participants view simulated “drive-bys” of various travel time signs.