Martin Böhm, Susanne Fuchs, Reinhard Pfliegl 1

Size: px

Start display at page:

Download "Martin Böhm, Susanne Fuchs, Reinhard Pfliegl 1"

Susan Austin
5 years ago
Views:

1 Martin Böhm, Susanne Fuchs, Reinhard Pfliegl 1 Driver Behavior and User Acceptance of Cooperative Systems based on Infrastructure-to- Vehicle Communication Submission date: 1 August 2008 Word count: 155 (abstract) (body) + (12 figures + 1 table) = words Authors: Martin Böhm (corresponding author), AustriaTech-Federal Agency for Technological Measures Ltd., Donau-City-Strasse 1, A-1220 Vienna, Austria, phone: , fax: , martin.boehm@austriatech.org Susanne Fuchs, Vereinigung High Tech Marketing, Lothringerstrasse 14/6, A-1030 Vienna, Austria, phone: , fax: , sf@hitec.at Reinhard Pfliegl, AustriaTech-Federal Agency for Technological Measures Ltd., Donau-City- Strasse 1, A-1220 Vienna, Austria, phone: , fax: , reinhard.pfliegl@austriatech.org

2 Martin Böhm, Susanne Fuchs, Reinhard Pfliegl 2 ABSTRACT Co-operative Systems applying infrastructure-to-vehicle (I2V) communication for Intelligent Transport Systems (ITS) are one of the key means to ensure safe and efficient driving through the increasing overloaded infrastructure. Within the European project COOPERS, that is a 48-month integrated project co-funded by the European Commission, a simulator tests of I2V communication systems have been performed with 51 participants to evaluate driver behavior and user acceptance. I2V communication systems influence the driver behavior in a positive manner. Drivers keep calmer in stress situations and the direct influence on road safety can be seen in reduced driving speeds previous to dangerous situations. So a positive support of the driver during dangerous situations could be achieved. User acceptance results show that the already high expectations of End Users towards Cooperative systems were outperformed. The fact that the test persons agreed to purchase cooperative systems like COOPERS as soon as commercially available underlines the positive attitude towards the system.

3 Martin Böhm, Susanne Fuchs, Reinhard Pfliegl 3 INTRODUCTION One of the main focuses of worldwide research and development (R&D) projects in the area of Intelligent Transport Systems (ITS) is the development of co-operative systems, where three areas can be distinguished: autonomous in-vehicle systems, vehicle-to-vehicle (V2V) communication systems, and infrastructure-to-vehicle (I2V) communication systems. The European Integrated Project COOPERS (Co-operative Systems for Intelligent Road Safety, that focuses on the last group, I2V communication systems, plans to connect vehicles on the motorway to the road infrastructure via continuous bidirectional wireless communication (see figure 1). For the I2V communication no specific communication technology is developed but existing networks are analyzed and tested in terms of their abilities to transmit accurate, high-quality traffic information directly to vehicle groups on a motorway segment. COOPERS will provide vehicles and their drivers with real-time safety related information of the current traffic infrastructure status which is location based a concept that is also followed by the Vehicle-Infrastructure Integration (VII) (1) and the Japanese Advanced Cruise-Assist Highway System Research Association (AHSRA) (2). It is expected that I2V communication has the potential to improve traffic management while simultaneously enhancing road safety. (3) FIGURE 1 COOPERS vision of continuous bidirectional I2V communication along motorways For this enhancement of road safety the first technological challenge is to guarantee a faster exchange of road-safety related information from the infrastructure side. Currently the delivery of information from the road operator to the drivers is done in Europe via broadcasted digital information using the Traffic Message Channel (TMC). (4) This information loop takes up to 10 minutes, which is much too long for safety applications. Within COOPERS this information gap will be reduced to 30 seconds from the generation of the information within the Traffic Control Centre (TCC) until its delivery to the end user. Below that 30 seconds threshold it is anticipated that direct V2V communication will take over.

4 Martin Böhm, Susanne Fuchs, Reinhard Pfliegl 4 The second challenge is to improve information accuracy. Information is sourced from various sensor technologies and fused intelligently with external services such as weather forecasts. For cooperative systems, messages need to be attached to locations, either the point of an event (e.g. an accident or the dynamically moving end of a traffic jam) or the start and end points for segment-specific information (e.g. slippery road surfaces or speed restrictions). The traffic information delivered to the driver will be presented language independent to ensure that all drivers in a multi-lingual Europe understand the content of the message. Within the COOPERS project the following safety relevant Information Services are defined: (5) Accident/Incident Warning (drivers are warned on an accident/incident ahead) Weather Condition Warning (drivers are made aware of environmental related problems ahead e.g. black-ice, fog, heavy rain, storm) Roadwork Information Lane Utilization Information (drivers are made aware of the lane control policy applied and the lane utilization information) In-Vehicle Variable Speed Limit Information Traffic Congestion Warning Intelligent Speed Adaptation (ISA) with Infrastructure Link (in comparison to the In-Vehicle Variable Speed Limit Information the motorway-operator-provided information must be very accurate and a continuous communication between infrastructure and vehicle must be provided) METHODOLOGY DESIGN FOR TESTING AND DEMONSTRATION Introduction Evaluation methodologies for the assessment of ITS systems and its performance are usually developed from a technical perspective and from a driver behavior point of view. Within COOPERS the combination of both aspects in a stringent and consistent way is performed. Additionally user acceptance is taken into account, which is usually addressed in economics, information systems and marketing research. FIGURE 2 The hierarchical assessment structure used in COOPERS As the main objective of COOPERS is related to safety, especially to enhance safe driving through the influence of timely and locally accurate traffic information, it is generally anticipated that this improved safety will be achieved primarily by helping drivers to avoid situations where risks of crashes are greater due to environmental, roadway, or traffic conditions. (6) However, traffic safety evaluation is a difficult task to assess in the field, primarily due to the

Martin Böhm, Susanne Fuchs, Reinhard Pfliegl 5 relative infrequency of accident occurrences, the need for large samples to identify with reasonable confidence a modest change in safety, and that it

5 Martin Böhm, Susanne Fuchs, Reinhard Pfliegl 5 relative infrequency of accident occurrences, the need for large samples to identify with reasonable confidence a modest change in safety, and that it is often difficult to attribute the cause of an accident to a particular factor. Instead, it is more usual to focus on the behavioral aspects of the driving task (7), where aspects are selected based on known adverse effects on traffic safety, such as insufficient safety margins in lateral and longitudinal positioning. Traffic safety effects are then confined to an extrapolation from these test results, although even then it is doubtful whether complex, often contradictory, results can be translated into reliable estimates of changes in safety in a road network. (8) It needs to be noted that there is no scientifically established causal connection between technical equipment and driver behavior, which implies that no direct calculation regarding the gain in safety based on a particular service provision can be made. Therefore the COOPERS assessment methodology is structured in a technical and a behavioral level, as depicted in figure 2. Technical Assessment The technical evaluation of the equipment (the overall system layout can be seen in figure 3) will be done mainly in extensive laboratory tests for the components and for the whole system on the single demonstration sites. The communication level will show the full functionalities of the information and communication systems with the services. These tests will be conducted with faked messages. A test site is assumed to fully function on a technical level, when there are no mistakes in the logged protocols of the sent and received information of three simultaneous test drives over the test sites. At this stage there are no requirements for the drivers of the test vehicles themselves. (9) FIGURE 3 The overall COOPERS system layout Driver Behavior and User Acceptance Assessment For the assessment of driver behavior and user acceptance of cooperative systems based on I2V communication firstly a simulator study was conducted. Such simulator studies are very common to test cooperative system in a safe environment first as well as simulate safety critical

Martin Böhm, Susanne Fuchs, Reinhard Pfliegl 6 driving scenarios. Similar simulator studies have been performed by the European Safespot project (http://www.safespot-eu.

6 Martin Böhm, Susanne Fuchs, Reinhard Pfliegl 6 driving scenarios. Similar simulator studies have been performed by the European Safespot project ( for the Intelligent Cooperative Intersection Safety System (IRIS) (10) or by the U.S. Department of Transportation for the Cooperative Intersection Collision Avoidance Systems (CICAS) research initiative (11). Secondly field tests will be carried out at various locations in Austria, Belgium, France, Germany, Italy, and the Netherlands. The simulator study provided clearly defined and exactly the same traffic instances for each test driver and thus builds the basis for establishing firmer correlations between traffic circumstance, information provision, and driver reaction. The field trials, on the other hand, cannot replicate the repetitiveness of the same traffic events but should show the driver reaction under real conditions. Hence, the tests have to follow the same principles and procedure in both, the simulator study and the field tests, otherwise no coherent derivations can be attempted. The derivations themselves will be based on four levels: The schema of parameters (according to infrastructure, vehicle, TCC, driver) The testing procedure The measurement methods The analysis method For the evaluation of the communication process, the information provision, the impact on the driver behavior, the vehicle, and the traffic flow, an extensive list of parameters is defined. Since different demonstration sites measure different units, the parameters have also been examined with alternative combinations, in order to establish one comparative basis from a unit point of view, which will additionally be standardized or normalized. The measurements for driver behavior includes also a physiological measurement equipment (PME) consisting of portable bio-signal data acquisition instruments and analysis tools (see figure 4). The possible multimodal bio-signals allow to record data from heart-, brain-, muscle-activity, eye movement, respiration, galvanic skin response and other body signals. The PME is synchronized via radio time with the vehicle performance in order to provide an accurate picture of the events in question. FIGURE 4 Test person equipped with the physiological measurement equipment The analysis of driver behavior of cooperative systems based on I2V communication starts with the comparison of driving without and with the service information. Hereby several

7 Martin Böhm, Susanne Fuchs, Reinhard Pfliegl 7 parameters are collected, starting from the usual vehicle performance measures (e.g. speeding, headway) up to drivers' physiological measures. In addition a driver behavior and a user acceptance model is used in order to attempt a step beyond the exploratory level. (12-15) The testing procedure for both, the simulator and the field tests is laid down in figure 5. User Groups Group 1 Group 2 Driver Selection with Filter Questionnaire Pre- test Test Driving without and the with the provisional fitted physiological measurement equipment Pre-questionnaire Pre-questionnaire Driving I without Services with Services Break Driving II with Services + GD without Services + GD Post-questionnaire In-depth interviews With selected drivers FIGURE 5 Testing Procedure (GD=Ghost Driver) Post-questionnaire The COOPERS technology can improve efficiency, effectiveness and safety of roads if it is accepted and thus used in everyday conditions by a large share of private and professional drivers. User Acceptance, usually not considered as one main part in a telematics and network performance assessment, is measured in various facets, whereas the main predictors are ease of use and usefulness which account for up to 57 % of all envisaged measures. (16-17) Technology or user acceptance is thus defined as the degree to which individual users will use a given system when usage is voluntary or discretionary. (18) The acceptance of a product or service refers to the continued usage of it. It can be measure by two parameter values: frequency of use and intensity of use. For user acceptance, a mixed method field design is used: investigations are performed with both quantitative and qualitative approaches to account for the special conditions with COOPERS test sites across Europe. A validated and pre-tested questionnaire is used to test standard items in the Technology Acceptance Model - TAM. (16) The concept of TAM, which tries to explain acceptance and the use of technology, can be seen in figure 6. In addition, qualitative interviews will serve as basis for further understanding and source of information.

8 Martin Böhm, Susanne Fuchs, Reinhard Pfliegl 8 Perceived Usefulness Attitude Toward Using Behavioral Intention to Use Actual System Use Perceived Ease of Use FIGURE 6 Technology Acceptance Model (TAM) RESULTS OF THE SIMULATOR STUDY Introduction The designed methodology attempts an interdisciplinary combination between driver behavior and user acceptance and provides a comprehensive picture, a realistic estimate for the application and acceptance of ITS-technologies and the implications for safe behavior and traffic safety in general. The following parts describe the first results from the COOPERS simulator study achieved in User Acceptance and Driver Behavior. In total, 51 test persons participated in the COOPERS simulator study. The distribution between female and male participants was equal (49 % female, 51 % male). Of these test persons 65 % belonged to an age group between 30 and 44 years, 33 % were between 45 and 59 years and 2 % up to 29 years old. All of the participants had at least some driving experience, most of them (68 %) stated that they drive daily or several times a week on motorways, 27 % stated to drive on motorways mostly on weekends of holidays. Only 6 % are driving on motorways rarely. Driver Behavior Results Beside the assessment of first user acceptance tests the main reason for setting up the simulator study within COOPERS was to fine tune the system to inform the driver in time about upcoming dangerous situations (e.g. when is an information to the driver early enough?). A second advantage of testing the system in a simulator is the demonstration of dangerous events that might be not testable in real world conditions. This includes the monitoring of the single driver in a very controlled way. Within the simulator study the following scenarios have been simulated: Accident/incident warning with an approaching ambulance from behind. Here an intermediate reaction of the driver is expected. Accident/incident warning with a wrong way driver warning. Here the time scale for the driver reaction is very short and a quick reaction is expected. Weather conditions warning with upcoming heavy fog, where a slow driver reaction is expected. Traffic Congestion Warning indicating the end of a congestion-zone with an expected fast driver reaction. As described above (see also figure 5) the whole simulation drive was done two times each 30 minutes, one time with COOPERS system on, one time with COOPERS system off.

Martin Böhm, Susanne Fuchs, Reinhard Pfliegl 9 Also the order of the events changed between the single test drives to ensure comparable results that rely on the service itself and not on outstanding

9 Martin Böhm, Susanne Fuchs, Reinhard Pfliegl 9 Also the order of the events changed between the single test drives to ensure comparable results that rely on the service itself and not on outstanding factors. The driver behavior evaluated can be distinguished into two groups: Objective Driver Behavior Subjective Driver Behavior Herby the objective driver behavior deals with direct measurable data (e.g. speed of the vehicle, lateral position of the vehicle), actions taken by the drivers (e.g. lane change, braking), and physiological measurements as described above. Beside the objective measurements a questionnaire deals with the subjective sensation of the driver concerning the driver's behavior (e.g. actions taken) and the test person's opinion on how they were influenced by the COOPERS system during the simulation drive. Objective Driver Behavior Results In all scenarios information of the upcoming dangerous event was given to the single drivers 2 kilometers ahead of the trouble spot. With the fog scenario it can be seen in figure 7 that the drivers reduce immediately after the receipt of the fog warning their driving speed by 10kph and arrive in the dangerous motorway section with a 15kph lower speed than without the system on. And also in the fog section itself the average speed is 5 to 15kph lower that without system. By driving with the system off the average speed was about 70kph which results in a braking distance of 70 meters. By having the speed reduced by 5kph to 65kph this braking distance is reduced drastically by more than 11% to 62 meters. These figures impressively indicate the positive safety impacts of cooperative systems like COOPERS. Fog-warning is given to drivers with system on Actual fogsituation FIGURE 7 Driver behavior with fog warning The congestion scenario showed a different picture. Also in this scenario an immediate speed reduction with the congestion information can be seen (figure 8). But in contrast to the fog scenario the average driving speed was reduced immediately after the event-information but then kept on one speed level until a distance of 800m previous to the event. With this distance a continuous reduction of the speed until the reach of the congestion zone can be noticed, where the average speed is drastically lower than without congestion warning (up to 30kph lower!). This later reaction of the driver on the systems information can be a hint of too early information

10 Martin Böhm, Susanne Fuchs, Reinhard Pfliegl 10 to the driver. It might be fine to inform the driver about an upcoming congestion zone 1km in front of the event. In this case the simulator study is also used to fine tune the COOPERS system for the field tests to ensure a maximum safety impact and acceptance by the driver. Congestionwarning is given to drivers with system on Congestion: Information is given 2 km ahead of the congestion Point of congestion Speed [km/h] System off System on Distance [m] FIGURE 8 Driver behavior with congestion warning Subjective Driver Behavior Results In all scenarios the drivers felt that the COOPERS system affected their driving behavior. This was mainly the case in the fog and the congestion scenario, where 92% of all test persons concluded, that their driving behavior was changed by enlarging driver attention to the upcoming event. In the other two scenarios - the ambulance approach and the wrong way driver scenario - all drivers felt they were supported in a difficult driving situation as they were informed in time about the upcoming dangerous event. TABLE 1 Subjective Driver Behavior in COOPERS Simulator (values measured on a 7 point likert-scale; 1 = no stress, 7 = fully stressed) Test scenario Subjective stress WITHOUT Subjective stress WITH COOPERS system COOPERS System (1-7) Ambulance Wrong Way Driver Fog Congestion warning In all driving situations the test drivers were calmed by the COOPERS system, as it can be seen in table 1. Hereby the reduction of the stress level was between 58% (for wrong way driver warning) and 69% (for the ambulance scenario). However it can be seen, that especially for the wrong way driver warning the subjective stress level can be reduced, but is still very high. However, in combination with the decision support of the COOPERS system, it is possible to positively support drivers in such dangerous situation with accurate and timely information.

11 Martin Böhm, Susanne Fuchs, Reinhard Pfliegl 11 User Acceptance Results As discussed in the methodology section, perceived usefulness and perceived ease of use of a system investigated are the strongest predictors of actual system use and thus user acceptance. For this reason, the measures of the COOPERS simulator study for perceived usefulness and perceived ease of use as well as the intention to use are described here in more detail. Figure 9 shows the results for the measure perceived usefulness. It depicts the single questions that were asked to the test drivers and shows the likert-scale, where respondents were asked to rank their answers in a continuum between strongly agree and strongly disagree. The figure shows, that the test person had very positive expectations towards the COOPERS system already before they actually experienced it the green line indicates this expectations towards the usefulness of the system stated by the test drivers in the pre-questionnaire. The pink line shows the average rating of the respondents after experiencing the COOPERS system. The figure shows, that the actual COOPERS system experience outperformed the test drivers expectations: in average they found the system even more useful during driving than expected, they found that the system enables to accomplish driving tasks more quickly than expected before driving with the system, they found that the system increases driving safety more than expected, and so on. Only in case of the question using the system I can move from A to B more quickly and using the system I can better conform to traffic rules the system did not outdo the test driver's expectations. I expect / I found to find the system useful during driving using the system enables me to accomplish driving tasks more quickly Strongly agree Neither Strongly disagree using the system increases my driving safety If I use the system, I will increase my chances of planning my driving more efficiently before after using the system I can move from A to B more quickly using the system I can better conform to traffic rules using the system I will enjoy improved driving convenience using the system I have improved information about road conditions FIGURE 9 Results for Perceived Usefulness of the COOPERS system Figure 10 shows the results of the pre- (in green) and after- (in pink) questionnaire concerning the construct Perceived Ease of Use. Ease of Use is besides Usefulness the strongest indicator of Technology Acceptance. The figure shows that in every single question that were asked in connection with how easy the system is perceived, the already quite high expectations of the users were outperformed by the actual system experience. In average, the test persons stated that they strongly agree that the interaction with the system was clear and understandable and that they find the system easy to use, etc.

12 Martin Böhm, Susanne Fuchs, Reinhard Pfliegl 12 I expect / I found Strongly agree Neither Strongly disagree my interaction with the system will be clear and understandable it will be easy for me to become skilful at understanding the system I will find the system easy to use before after the signs on the screen to be easily comprehensible the signs on the screen to be easily readable FIGURE 10 Results for Perceived Ease of Use of the COOPERS system As described above, the expectations of the test drivers towards the system were outperformed by the system performance in terms of how easy the system is to use and how useful the system is for driving. The test drivers were also asked, whether they intended to use a COOPERS system in the future. Figure 11 shows the results for the Intention to Use of the COOPERS system. Again, the answers given to the questions after experiencing the system were even more positive than before experiencing the system. After using the system, in average the respondents agreed that they would buy the system when commercially available. Strongly agree Neither Strongly disagree As soon as commercially available, I intend to use the system in the next 6 month I would recommend my friends to use the system I would buy the system when commercially available If I had a system I would use it before after If I had the system I would adjust my driving style to the recommendations of the system FIGURE 11 Results for Intention to Use of the COOPERS system Overall, the test drivers reacted in a very positive way to the COOPERS system. All major indicators for User Acceptance rank exceptionally high, and are positive in a before/after

13 Martin Böhm, Susanne Fuchs, Reinhard Pfliegl 13 comparison. Especially the very easy to use interface to the user and the useful COOPERS services seem to have a good impression on end users targeted. The results achieved in the simulator study are promising and the expectations towards the field tests are high. The COOPERS system was highly accepted by drivers in a simulated environment. The field tests will show if COOPERS can achieve the same outstanding results on a real European motorway. OUTLOOK TO THE FIELD TESTS In autumn 2008 COOPERS goes on the road the system will be tested across European motorways. The selected test sites (see figure 12) are heavily used TREN motorway corridors. The demonstration will show real events (e.g. speed profile, road works) and during the demonstration each single gantry along the test-track will be addressed. In the field tests, the same testing methodology will be applied as in the simulator study. This ensures the comparability of results and will reveal interesting insights for the further research and development as well as deployment of co-operative systems. FIGURE 12 COOPERS test sites CONCLUSIONS AND LIMITATIONS First results concerning driver behavior and user acceptance of cooperative systems achieved in the simulator study conducted in the European COOPERS project give very promising results in both, user acceptance and positive influence in driver behavior. Hereby especially the driver behavior in safety critical situations is positively influenced by reducing the stress level of the driver and simultaneously enhancing road safety in critical driving situations by reducing driving speed and enlarging driver attention. Technology Acceptance measurement of the COOPERS system show that end user expectations are high towards co-operative services. However, experiences in the simulator outperform these expectations by far, test persons were keen to buy a COOPERS system as soon as commercially available. Long-range adaptive behaviors might reduce the benefits of some ITS services (19). This effect has not been investigated in the current study and needs further research in future methodological designs of ITS simulator and field tests. Further, the effects of error in the system and its potential impact on driver behavior and user acceptance have not been researched in this study, but are an important field of research for future studies.

14 Martin Böhm, Susanne Fuchs, Reinhard Pfliegl 14 Field tests carried out for example already in Sangubashi (Japan) by AHSRA support our positive results (2). Tests on major motorway stretches across Europe will show, if the simulator results will be valid also for real world conditions. ACKNOWLEDGEMENT Following actors have contributed to the elaboration of the related reports within the COOPERS project: Doris Bankosegger, Alexander Frötscher, Christoph Hecht, Mattias Hjort, Robert Kölbl, Meng Lu, Selina Mardh, Andy Richards, and Thomas Scheider. REFERENCES 1. Shladover, S.E. Preparing the Way for Vehicle-Infrastructure Integration. California PATH Research report, California Partners for Advanced Transit and Highways Mizutani, H. Field Operation Tests on the Sangubashi Section of Metropolitan Expressway No. 4. Advanced Cruise-Assist Highway System Research Association, Accessed October 22, Böhm, M., Frötscher, A., McDonald, M., and Piao, J. Towards cooperative traffic management - An overview of the COOPERS project. In: Eurotransport Magazine: Issue 2, Russell Publishing Limited, Brasted, 2007, pp Schweiger, C.L. and Shammout, K. Strategies for Improved Traveller Information. In: Transit Cooperative Research Program: Report 92, TRB, National Academies, Washington D.C., 2003, pp McDonald, M. Summary Report on Safety Standards and Indicators to Improve the Safety on Roads. COOPERS Report D5-2100, Southampton, 2007, pp Federal Highway Administration. Intelligent Transportation Systems benefits: 2001 update. FHWA-OP , U.S. Department of Transportation, Intelligent Systems Joint Program Office, Brookhuis, K.A., D. de Waard, and W.H. Janssen. Behavioural impacts of Advanced Driver Assistance Systems an overview. In: European Journal of Transport and Infrastructure Research, 1(3), Delft, 2001, p Carsten, O. and L. Nilsson. Safety assessment of driver assistance systems. In: European Journal of Transport and Infrastructure Research, 1(3), Delft, 2001, p Reumann, C., Gruber, T., Selhofer, A., and Schoitsch, E. Test Guidelines. COOPERS Report D10-A-IR , Vienna, Vreeswijk, J. Driving simulator study for Intelligent Cooperative Intersection Safety systems (IRIS). In: Proceedings of the 7th European Congress and Exhibition on Intelligent Transport Systems and Services, CD-ROM, Ertico, Brussels, Bischoff, D. Developing guidelines for managing driver workload and distraction associated with telematic devices. Washington DC, Ahmed, K.I., et al. Models of Freeway Lane Changing and Gap Acceptance Behavior. In: Proceedings of the13th International Symposium on Transportation and Traffic Theory (ISTTT). Lyon, France Toledo, T., H.N. Koutsopoulos, and K. Ahmed, Estimation of Vehicle Trajectories with Locally Weighted Regression. In: Transportation Research Record, (1999), 2007, p Toledo, T., H.N. Koutsopoulos, and M. Ben-Akiva. Modeling Integrated Lanechanging Behavior. In: Transportation Research Record, (1857), 2003 p

15 Martin Böhm, Susanne Fuchs, Reinhard Pfliegl Toledo, T., H.N. Koutsopoulos, and M. Ben-Akiva. Integrated Driving Behavior Modeling. In: Transportation Research C, 15(2), 2007, p Davis, F. D. Perceived usefulness, perceived ease of use, and user acceptance of information technology. In: MIS Quarterly, 13, 3, 1989, p Davis, F.D., R.P. Bagozzi, and P.R. Warshar. User acceptance of computer technology: a comparison of two theoretical models. In: Management Science, 35, 1989, p Morris, M.G. A longitudinal examination of information technology acceptance, In: School of Business. 1996, Indiana University, Indiana. 19. Smiley, A. and Grant, B. Behavioural Adaptation and Antilock Brake Systems. presented at IEA 1991, Paris, France, July, 1991.

TRB Workshop on the Future of Road Vehicle Automation

TRB Workshop on the Future of Road Vehicle Automation Steven E. Shladover University of California PATH Program ITFVHA Meeting, Vienna October 21, 2012 1 Outline TRB background Workshop organization Automation