`

`

`

`1. Report No.
`
`FHWA-RD-96-031
`4. Title and Subtitle
`
` Technical Report Documentation Page
`2. Government Accession No.
`3. Recipient's Catalog No.
`
`5. Report Date
`
`Mar-96
`
`TRAVTEK GLOBAL EVALUATION AND EXECUTIVE SUMMARY
`
`6. Performing Organization Code
`
`7. Author(s)
`
`8. Performing Organization Report No.
`
`V. W. Imnan, J. I. Peters
`9. Performing Organization Name and Address
`Science Applications International Corporation
`3045 Technology Pkwy
`Orlando, FL 32826
`12. Sponsoring Agency Name and Address
`
`Office of Safety and Traffic Operations R&D
`Federal Highway Administration
`6300 Georgetown Pike
`McLean, VA 22102-2296
`15. Supplementary Notes
`
`10. Work Unit No. (TRAIS)
`3B7A
`11. Contract or Grant No.
`DTFH61-91-C-00106
`13. Type of Report and Period Covered
`
`Final Report, Nov. 1991, June 1994
`14. Sponsoring Agency Code
`
`Contracting Officer’s Technical Representative: FrankMammano, HSR-12
`
`16. Abstract
`
`TravTek was an operational field test of an advanced traveler information systems (ATIS) and advanced traffic management
`systems (ATMS) technologies. This paper summarizess the findings from the series of studies that constituted the TravTek
`evaluation. Two field studies, three field experiments, and four analytical studies are summarized. The Rental User Study and
`Local User Study were naturalistic field studies of the use of the TravTek system by rental drivers and high-mileage local area
`residents respectively. The Yoked Driver Study, Orlando Test Network Study, and Camera Car Study were field experiments
`that empirically assessed the in-vehicle TravTek subsystem with respect to measures of performance that included trip plan-
`ning time, travel time, subjective workload, wrong turns, glance location, and glance duration. The Modeling Study extrapo-
`lated expected system performance from field studies and experiments for various levels of market penetration, traffic condi-
`tions not observed in the field, and measures of performance not directly measured in the field. The Modeling Study projected
`effects on fuel consumption, vehicle emissions, accident risk, and other measures for market penetration levels of 1 to 100 per-
`cent. The Safety Study reviewed and integrated safety-related statistics across all TravTek studies and expanded on Modeling
`Study methods to project safety benefits. The Architecture Study thoroughly documented the TravTek system and evaluated
`system components that included: communications, data bases, hardware, software, and system staffing.
`Study results showed that the TravTek system was reliable. The distributed information processing system was found to be vi-
`able. The system helped drivers save substantial trip planning and travel time. It also was effective in helping drivers avoid
`congestion. Both visitors and local users used the system frequently, and provided a median estimate of the value of the system
`in a new car of about $1000. The turn-by-turn Guidance Display and Voice Guide were very well received. Visitors and local
`users used these features for the majority of their trips, and results of field experiments suggest that the Guidance Display and
`Voice Guide yielded improved driving and navigation performance over navigating to unfamiliar destinations by conventional
`means. The Safety Study showed that the system was safe, and suggested a small safety benefit for a fully deployed system. The
`Modeling Study findings suggest that a TravTek system would benefit not only system users, but also non-equipped vehicles
`that share the road with system users. The TravTek operational test was a success. The TravTek evaluation demonstrated that
`users found the system useful, easy to use, and safe. Field experiments showed that the system reduced trip planning and travel
`time, and improved driving and navigation performance. System users indicated that they were willing to pay for a system such
`as the one they drove during the operational test.
`17. Key Words
`18. Distribution Statement
`
`TravTek, ATIS, ATMS, IVHS, ITS, Evaluation
`19. Security Classif. (of this report)
`
`No restrictions. This document is available to the public through
`the National Technical Information Service, Springfield, Virginia 22161
`20.Security Classif. (of this page)
`21. No of Pages 22. Price
`
`Unclassified
`Form DOT F 1700.7(8-72)
`
`101
`Unclassified
`Reproduction of completed page authorized
`
`ASUS-1014, Page 3
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`TABLE OF CONTENTS
`
`Page
`Section
`1
`EXECUTIVE SUMMARY.......................................................................................................
`1
`INTRODUCTION ................................................................................................................
`1
`The TravTek Partnership ................................................................................................
`1
`The TravTek System........................................................................................................
`2
`The TravTek In-Vehicle System......................................................................................
`3
`The Traffic Management Center ....................................................................................
`3
`The TravTek Information and Services Center..............................................................
`3
`The TravTek Network .....................................................................................................
`3
`THE TRAVTEK EVALUATION........................................................................................
`4
`Goals and Objectives .......................................................................................................
`4
`Approach ..........................................................................................................................
`4
`THE TRAVTEK STUDIES .................................................................................................
`5
`Field Studies .....................................................................................................................
`6
`Field Experiments ............................................................................................................
`7
`Analytical Studies ............................................................................................................
`8
`RESULTS .............................................................................................................................
`Did the System Work?...................................................................................................... 9
`10
`Did Drivers Save Time and Avoid Congestion? ...........................................................
`Will Drivers Use the System”......................................................................................... 10
`How Effective were tbe Turn-By-Turn, Moving Map, and Voice Guidance
`Displays?.............................................................................................................. 10
`Was TravTek Safe?......................................................................................................... 11
`Could TravTek Benefit Travelers Who Do Not Have the System?............................... 12
`Will People be Willing to Pay for TravTek Features?................................................... 12
`12
`CONCLUSIONS AND RECOMMENDATIONS .............................................................
`13
`Implications for Deployment .........................................................................................
`15
`INTRODUCTION ...................................................................................................................
`15
`THE TRAVTEK PARTNERSHIP ....................................................................................
`15
`THE TRAVTEK SYSTEM................................................................................................
`17
`THE TRAVTEK IN-VEHICLE SYSTEM ........................................................................
`18
`Data Base of Local Information ....................................................................................
`18
`Navigation Assistance ....................................................................................................
`19
`Route Planning ..............................................................................................................
`19
`Route Guidance .............................................................................................................
`20
`Real-Time Traffic Information......................................................................................
`21
`Location Assistance .......................................................................................................
`22
`Built in tutorial and help ...............................................................................................
`22
`TRAFFIC MANAGEMENT CENTER.............................................................................
`24
`TRAVTEK INFORMATION AND SERVICES CENTER..............................................
`26
`THE TRAVTEK TRAFFIC NETWORK .........................................................................
`29
`TRAVTEK EVALUATION ...................................................................................................
`
`
`iii
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`TABLE OF CONTENTS (continued)
`
`Section
`Page
`OPERATIONAL FIELD TEST OBJECTIVES AND EVALUATION GOALS . . . . . . . . . . . . . 29
`VARIABLES OF INTEREST............................................................................................
`30
`Vehicle Subsystem Variables .........................................................................................
`31
`System Variables............................................................................................................
`32
`CRITERION MEASURES ................................................................................................
`32
`32
`In-Vehicle Systems .........................................................................................................
`34
`TravTek System Measures ............................................................................................
`34
`TRAVTEK EVALUATION DATA SOURCES................................................................
`35
`Questionnaires ...............................................................................................................
`35
`Debriefings .....................................................................................................................
`36
`In-vehicle data logs ........................................................................................................
`TravTek Information and Services Center (TISC) logs ............................................... 36
`37
`Traffic Management Center (TMC) logs ......................................................................
`37
`Freeway Management Center (FMC) Logs ..................................................................
`37
`Observer Logs ................................................................................................................
`38
`Camera Car Video .........................................................................................................
`38
`Camera Car Data Log ...................................................................................................
`39
`TRAVTEK STUDIES .............................................................................................................
`39
`NATURALISTIC FIELD STUDIES .................................................................................
`40
`Rental User Study..........................................................................................................
`41
`Local User Study............................................................................................................
`41
`FIELD EXPERIMENTS ....................................................................................................
`42
`Yoked Driver Study .......................................................................................................
`43
`Orlando Test Network Study ........................................................................................
`44
`Camera Car Study .........................................................................................................
`45
`ANALYTICAL STUDIES..................................................................................................
`45
`Modeling Study..............................................................................................................
`47
`Safety Study ...................................................................................................................
`48
`Architecture Evaluation ................................................................................................
`50
`Global Evaluation ..........................................................................................................
`51
`EVALUATION RESULTS .....................................................................................................
`DID THE TRAVTEK SYSTEM WORK“......................................................................... 51
`Did the System Function According to Specification3.................................................. 51
`Did End Users Perceive the System to Work?............................................................... 54
`DID DRIVERS SAVE TIME AND AVOID CONGESTION”.......................................... 55
`Did the TravTek Trip Planning Feature Save Time”.................................................... 55
`Did TravTek Route Guidance Save Time?.................................................................... 56
`Did Real-Time Traffic Information Result in a Time Savings Benefit? ......................56
`WILL DRIVERS USE THE SYSTEM’............................................................................. 58
`58
`What Users Did ..............................................................................................................
`59
`What drivers said about using TravTek.......................................................................
`
`iv
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`ASUS-1014, Page 6
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`EXECUTIVE SUMMARY
`
`INTRODUCTION
`
`TravTek, short for “Travel Technology,” was an Intelligent Transportation Systems (ITS) opera-
`tional field test. The purpose of TravTek was to perform research, development, test, and evalua-
`tion of advanced traveler information systems (ATIS) and advanced traffic management systems
`(ATMS) concepts.
`
`The TravTek Partnership
`
`TravTek was a joint public and private sector operational field test of an advanced traveler infor-
`mation and traffic management system (ATIS/ATMS). Public sector participants were the City of
`Orlando, the Federal Highway Administration (FHWA), and the Florida Department of Transpor-
`tation. The American Automobile Association and General Motors were the private sector par-
`ticipants.
`
`The TravTek System
`
`TravTek consisted of three major subsystems:
`1. One-hundred TravTek vehicles.
`2. The Orlando Traffic Management Center (TMC).
`3. The TravTek Information and Services Center (TISC).
`An overview of the relationships between TravTek subsystems is shown in figure 1. The TravTek
`System Architecture Evaluation and reports by Sumner provide detailed descriptions of the
`TravTek system. (1,2,3) An inherent feature of each subsystem was automated data recording for
`evaluation purposes. These evaluation features are discussed in later sections of the report. Each
`of the TravTek partners was responsible for providing and maintaining specific sub-systems. The
`responsibilities of General Motors included providing the vehicles, the interface between the TMC
`and test vehicles, a data base, and systems engineering. FHWA provided for the TravTek evalua-
`tion, the system manager for the TMC, leasing of the radio subsystem, support for the Florida
`Department of Transportation’s freeway management center, and assisted the City of Orlando in
`operating and maintaining the TMC. The American Automobile Association provided a TravTek
`Information and Services Center that maintained the rental reservation system, the navigation data
`base, the local information data base, and 24-hour help desk services. The City of Orlando pro-
`vided coordination of the TMC with other traffic management facilities, space, hardware, and
`software for the TMC, and an interface with the city’s traffic signal system. The Florida Depart-
`ment of Transportation provided the freeway surveillance system on I-4, the interface of the sur-
`veillance system with the TMC, and maintenance of the TravTek traffic link-node data base.
`
`ASUS-1014, Page 11
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`The Navigation Plus configuration included all Services and Navigation configuration features
`plus the display of traffic information and route planning around congestion based on real-time
`traffic information.
`
`Three configurations, rather than just the Navigation Plus configuration, were included to support
`research and evaluation. By providing different features to different drivers, or more than one
`configuration to the same drivers, the evaluators were better able to evaluate the features with re-
`spect to driver behaviors and perceptions.
`
`The Traffic Management Center
`
`The TMC received traffic information from a number of sources, processed these data, and
`transmitted current traffic conditions to the TravTek vehicles. Data sources included the Florida
`Department of Transportation Freeway Management Center, Orlando’s traffic control system, a
`network of public and private sector reporting stations, and, most importantly, the TravTek vehi-
`cles. Information cleared through the system included link travel times, incident status, and the lo-
`cation of congestion. Link travel times were broadcast once each minute for any of 1,488 traffic
`links for which travel times were greater than nominal. Evaluation data collection functions in-
`cluded the logging of all communications between the vehicles and the TMC. These communica-
`tions included a record that was updated each minute of the locations of all TravTek vehicles,
`
`The TravTek Information and Services Center
`
`The American Automobile Association operated the TISC. The most visible function of the TISC
`was to provide help desk services to TravTek users. The TISC also provided and maintained the
`navigable map data base used in the vehicles. The data base represented a 3 100 km2 area of met-
`ropolitan Orlando and consisted of approximately 74,000 navigable roadway links. The data base
`was updated and corrected at intervals throughout the operational test. The TISC also managed
`the local information directory data base and reservation data base. Evaluation data collection
`functions of the TISC included reservations and help desk contact logs.
`
`The TravTek Network
`
`In the coverage area, two types of data base links were defined: TravTek links, and TravTek
`Traffic Network links. TravTek links were defined in the navigable data base maintained by the
`TISC. There were approximately 74,000 of these navigable links representing approximately
`16 000 km of roadway. TravTek Traffic Network links represented sections of roadways for
`which real-time traffic information could be transmitted. There were 1,488 TravTek Traffic Net-
`work links that covered a distance of 1 854 km.
`
`THE TRAVTEK EVALUATION
`
`Proponents of ITS technologies such as vehicle navigation, ATIS, and ATMS envision the wide-
`spread application of these technologies to improve transportation efficiency, safety, driver satis-
`faction, and driver security. The TravTek partners identified and tailored their TravTek opera-
`
`ASUS-1014, Page 13
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`assessments of TravTek, and their use of the vehicles was recorded in electronic data logs in the
`vehicle, at the TMC, and at the TISC.
`
`The Local User Study recruited 53 Orlando residents to drive TravTek vehicles for a period of 6
`to 8 weeks. For this study, residents were selected because they drove more frequently than the
`average driver. To provide an adequate sampling of the driving population, other driver selection
`criteria included age and gender. In addition to examining how local residents would use the sys-
`tem, this study enabled an examination of how use changed over time. It was anticipated that after
`2 months, usage would approximate that which might be seen with a mature system - after the
`novelty wore off.
`
`Field Experiments
`
`Whereas the Rental User Study and Local User Study examined how drivers would use the sys-
`tem when free of constraints, the field experiments were tightly focused on specific behavioral and
`system issues. In these studies, drivers were asked to drive from specified origins to specified
`destinations. Origins and destinations were in residential neighborhoods such that all drivers, even
`local drivers, needed some kind of assistance (i.e., TravTek, a paper map, or other instructions) to
`plan the routes. In these studies, observers rode along with the drivers to record data that could
`not easily be captured by the on-board electronic systems.
`
`The Yoked Driver Study focused on the benefits of real-time information.(5) In this study, sets of
`three vehicles left the same origin for the same destination, with one vehicle in each set configured
`to one of the three vehicle configurations: Services, Navigation, and Navigation Plus. Trips in this
`study were made during the evening peak travel period. In the Services configuration, drivers
`planned and drove their routes as they normally would without TravTek. With the Navigation
`configuration, drivers planned and drove routes using TravTek, but without the benefit of real-
`time traffic information. With the Navigation Plus configuration, drivers planned and drove routes
`using the default TravTek display configuration, and the routes were optimized (to minimize
`travel time) by the incorporation of real-time traffic information.
`
`The Orlando Test Network Study examined driving and navigation performance as a function of
`the display alternatives offered by the TravTek system. (6) Two visual route guidance displays were
`evaluated: a turn-by-turn Guidance Display that minimized information content to that required
`to navigate, and a moving Route Map that displayed planned routes over an electronic version of
`a traditional map. A supplemental synthesized speech Voice Guide was evaluated both by itself
`and in combination with the two visual displays. The study examined performance both in day and
`night driving environments.
`
`The Camera Car Study focused on safety and human factors issues related to the use of ATIS
`displays.(7) The design of the Camera Car Study was similar to that of the Orlando Test Network
`Study. What made the Camera Car Study unique were changes necessary to focus on age and ex-
`perience with use of the TravTek system and additional data collection instrumentation. Four
`video cameras were installed. One camera was focused on the driver’s eyes and enabled detailed
`examination of glance patterns. Another camera focused on the forward roadway and enabled
`detailed analysis of the traffic environment. A third camera looked over the driver’s shoulder to
`
`6
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`ASUS-1014, Page 16
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`enable recording of hand and foot movements. A fourth camera was attached outside the left side
`of the car and recorded lane position and lane excursions. Additional sensors in the camera car re-
`corded lateral and longitudinal acceleration, steering wheel position, and vehicle speed.
`
`Analytical Studies
`
`The field studies and experiments focused on data collection to support the evaluation of
`TravTek. The four analytical studies that are described below used data from the field studies,
`field experiments, and other sources to extend the system evaluation.
`
`Modeling Study. This study had three main objectives:
`1. To extrapolate from the available field data the expected performance of a TravTek
`type system for levels of market penetration ranging from 1 percent to 100 percent,
`2. To extrapolate the expected performance of a TravTek system in terms of measures
`such as vehicle stops, fuel consumption, vehicle emissions, and accident risk, that were
`not always directly observed during the field test.
`3. To estimate the potential impact on the benefits of the TravTek system for conditions
`not necessarily encountered in Orlando during the field test, such as different levels of
`traffic congestion, different incident durations, and different levels of routing quality
`for either the TravTek or the non-TravTek vehicles.(8)
`Computer modeling was employed to extrapolate from the available data. The model that was
`employed, INTEGRATION, was capable of simulating the behavior of both TravTek equipped
`and non-equipped vehicles such that numerous scenarios could be evaluated. Data from the other
`TravTek studies, as well as data collected as part of the modeling study, were used to calibrate
`the computer model. Of particular importance, was the ability of the model to handle driver be-
`haviors that were affected by TravTek, such as the propensity for making wrong turns and the
`propensity to choose roads of a particular class.
`
`Safety Study. The objectives of this study were to determine:
`
`l If the users of the TravTek system as deployed in Orlando, experienced a different level
`of safety than drivers of comparable vehicles without the TravTek system.
`. How the different TravTek configurations affected the safety experience of the drivers.
`l How the safety experience as observed in Orlando for the 100 vehicles deployed in the
`operational field test would change as a function of the level of market penetration - as
`the system was more widely deployed.(9)
`
`In order to meet the objectives, a methodology was developed that included the following four
`analytical steps:
`
`l Establishment of facility and traffic volume effects on base accident rate.
`l Evaluation of incidents and accidents that involved TravTek vehicles.
`l Estimation of potential safety impacts of TravTek in-vehicle devices.
`. Modeling the potential safety impacts of TravTek.
`
`7
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`Travel Time
`
`Travel Distance
`
`Vehicle Stops
`
`Wrong Turns
`
`Fuel Consumption
`
`1
`
`I
`
`Emissions
`
`Accidents
`
`0%
`
`5% 1 0 % 1 5 % 2 0 % 2 5 % 3 0 % 3 5 % 4 0 %
`Percent Reduction
`Figure 3. Some of the projected benefits of the TravTek system.
`
`Did the System Work?
`
`The TravTek system was very reliable. System up-time exceeded 96 percent. Vehicle-to-TMC
`and TMC-to-vehicle communications were reliable enough to meet system requirements. The
`probe vehicle concept worked very well. The TravTek vehicles distributed themselves across the
`network very well, such that with a greater number of vehicles deployed, very good network cov-
`erage would be achieved for obtaining probe vehicle travel times. The distributed architecture
`performed well. System reliability and the perception of reliability resulted, in great measure, from
`the ability of the vehicles to perform their own route planning. Centralized route planning, the al-
`ternative to a distributed system, would have placed far more demands on TMC infrastructure
`while at the same time increased the vulnerability of the system to single point failures.
`
`Although the map data bases posed formidable maintenance challenges, the overall accuracy of all
`TravTek data bases was high. The fuzzy logic algorithm for fusing traffic data at the TMC
`worked well. The TMC operator interface functioned properly, but recommendations for im-
`provement were made in the TravTek System Architecture Evaluation report.(‘) The TravTek
`system provided a very high level of automation: travel time data were collected, processed, and
`distributed to the vehicles without the need for operator intervention. Incident data did require
`operator intervention, and changes in operator training and the operator interface were recom-
`mended in the TravTek System Architecture Evaluation report.“)
`
`A need for better incident reporting was identified. The TravTek system did not have enough ac-
`tive incident data sources. Although a sufficient number of sources were identified, not all sources
`
`ASUS-1014, Page 19
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`were on line during the test. A need for procedural changes to increase incident reporting timeli-
`ness was also identified.
`
`Drivers found the system to be easy to learn, easy to use, and useful. Aside from the reliability of
`traffic information, users perceived the system to work well.
`
`Did Drivers Save Time and Avoid Congestion?
`
`TravTek was found to save trip planning time and to reduce travel time. Real-time traffic infor-
`mation did not further reduce TravTek users’ travel times, but the modeling results indicate that
`when using real-time traffic information, TravTek reduced network congestion and therefore re-
`duced overall network travel times.
`
`In all three field experiments the results were uniformly positive: for trips to unfamiliar destina-
`tions, both visitors and local users saved considerable time in planning trips when they used the
`TravTek system. The savings using TravTek were measured against two alternative trip planning
`methods: (1) phone calls to request directions, and (2) consulting an AAA paper map. During the
`day, the majority of drivers not using TravTek chose to use the map, whereas at night the majority
`chose to call the TravTek help desk for instructions. In all cases, TravTek saved considerable
`planning time. Both visitors and local users saved time planning trips with TravTek: For planning
`a nominal 20 minute trip, visitors saved, on average, over 7 minutes and locals saved more than 4
`minutes.
`
`The TravTek route guidance system was found to reduce travel time in all three field experiments,
`regardless of the TravTek display configuration used to communicate routes to drivers. The
`TravTek Navigation Plus configuration was shown, in the Yoked Driver Study, to successfully
`avoid congestion. Although the TravTek system helped vehicles avoid congestion, there were no
`observed travel time savings associated with congestion avoidance. To avoid congestion, vehicles
`took slightly longer routes on lower class roadways and, as a result, travel time remained about
`the same.
`
`Will Drivers Use the System?
`
`Those rental users who drove with the Navigation Plus and Navigation configurations used the
`TravTek system on approximately 80 percent of all their trips. At the end of 2 months experience
`with the system, local users were still using TravTek to plan routes for over 40 percent of all their
`trips. Both actual usage and questionnaire responses indicated that people will use TravTek-like
`systems for route planning and route guidance. Services users utilized TravTek on 37 percent of
`their trips - an indication that there is a demand for in-vehicle data bases of local services and
`attractions even when not integrated with a navigation and route guidance system.
`
`How Effective were the Turn-By-Turn, Moving Map, and Voice Guidance Displays?
`
`There were remarkably few differences in driving performance among the alternative display con-
`figurations. Overall, workload measures indicated that any TravTek configuration was preferable
`to the control configurations Among TravTek displays, the Route Map without supplemental
`
`10
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`ASUS-1014, Page 20
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`Voice Guide instructions yielded slightly higher workload and marginally lower performance
`compared to: the Guidance Display (with or without Voice Guide); the Route Map with Voice
`Guide; or, the Voice Guide alone.
`
`Drivers generally reported that the TravTek route guidance options helped them pay more atten-
`tion to their driving and helped them find their way. Among the TravTek display combinations,
`the field experiments showed the Guidance Display with Voice Guide yielded the best safety-
`related driving performance.
`
`Rental users, who were largely visitors to Orlando, used the simplified turn-by-turn Guidance
`Display far more than the more information-dense Route Map. Rental users also tended to leave
`the Voice Guide on while they were driving - they drove with the Voice Guide on over 85 per-
`cent of the time.
`
`Local users also used the Guidance Display more than the Route Map, and kept the Voice Guide
`on more than off, but local users used the Route Map more than renters (about a third of the time)
`and drove with the Voice Guide on approximately 70 percent of the time.
`
`For route guidance, the TravTek results strongly support the use of supplemental voice instruc-
`tions as they yielded better performance than visual displays alone. In designing future systems, if
`a decision must be made between moving map and turn-by-turn displays,