Browsing by Author "Smith, Thomas J."
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Item Human Factors Evaluation of GAINS, a Prototype In-Vehicle Navigation System(Minnesota Department of Transportation, 1999-04) Smith, Thomas J.; Wade, Michael G.; Hammond, CurtisThis project evaluated how driver interaction with an in-vehicle navigation system (IVNS) affects driving performance and safety. Researchers collected measures of simulated driving performance during interaction by 13 different subjects with an IVNS digital map display, using a Honda Acura placed within a fixed-base wrap-around driving simulator. Subjects (Ss) navigated along a maze-like route laid out within a simulated road grid. Dummy Global Positioning System (GPS) coordinates, corresponding to the position of the vehicle in the grid, were transmitted to the IVNS and updated continuously as vehicle position in the simulation environment changed. A digital map of the grid, with an icon representing vehicle representing vehicle position superimposed, was displayed on a laptop computer placed in the Acura. Under the control condition, Ss were not given turn instructions. Results indicate that for the test relative to the control condition: * Visual interaction with the IVNS display was greater and task completion times longer. * More variability in vehicle control was observed for measures of average vehicle speed, peak speed, percent braking time, peak braking pressure, and vehicle heading. Subjective responses from simulated driving and a separate group of on-road Ss identify both navigation benefits and possible safety problems with the system. It is a reasonable assumption that increased variability in driving performance elevates driving accident risk. Both the simulated driving and subjective response results, therefore, point to possible safety implications in IVNS use for the driving public. The findings suggest that as IVNS use becomes more widespread, both navigation benefits and possible adverse driving safety effects of such systems need to be considered.Item Reliability of Heuristic Evaluation during Usability Analysis(University of Minnesota College of Education & Human Development, 2021) Smith, Thomas J.; Kheng, CindyScientific reliability --- the degree to which a research method produced stable & consistent results --- represents a major linchpin of tenable scientific research. A number of different studies support the conclusion that usability testing of software interfaces lacks scientific reliability. The present report augments this conclusion with findings that heuristic evaluation, the second major pillar of usability analysis, also lacks reliability. We conclude that key priority of "usability science" should be to initiate a systematic program of inquiry to investigate the degree to which this term has meaning.Item Warning Efficacy of Active Versus Passive Warnings for Unsignalized Intersection and Mid-Block Pedestrian Crosswalks(Minnesota Department of Transportation, 2009-01) Smith, Thomas J.; Hammond, Curtis; Somasundaram, Guruprasad; Papanikolopoulos, NikolaosThis study evaluated the efficacy of active versus passive warnings at uncontrolled pedestrian (ped) crosswalks (Xwalks), by comparing how these two warnings types influenced behavior of drivers approaching such Xwalks. Vehicle-Xwalk interactions were observed at 18 sites with passive, continuously flashing, or ped-activated warnings, yielding 7,305 no ped present and 596 ped present interactions. Vehicle velocities and accelerations were averaged for each interaction. Findings show no significant effect of warning type on overall velocities for either interaction type. With peds present only, for average velocities at successive 5m distances from the Xwalk, a downward trend in velocities from 25 to 5m is observed for passive and active warning sites, but not for pedactivated warning sites. Various lines of evidence point to a number of sources of ambiguity regarding the salience of uncontrolled Xwalk warnings, resulting in behavioral uncertainty by drivers interacting with such warnings. Mixed findings on effects of warning type in this study point to the need for further analysis of this problem area.