Browsing by Author "Smith, Thomas J"
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Item Effects of Vision Enhancement Systems (VES) on Older Drivers' Ability to Drive Safely at Night & in Inclement Weather:Visual Human Factors:Analysis of In-Vehicle Heads Up Display (HUD)(2002-06-01) Smith, Thomas JThe HUD system is intended to improve driving performance in conditions of limited visibility. The HUD system projects lines that correspond to the sides and center line of the roadway onto the windshield of the vehicle, thus aiding the driver in times of low visibility. The author found that the simple, monochromatic image avoided many problems associated with other more complicated HUD designs and that the use of conformal imagery (projecting the image over the actual view) enhanced the effectiveness of the system. This analysis complements the analysis of simulated in-vehicle head-up display done by Caird, Horrey, Chugh, and Edwards. Their report, The Effects of Conformal and Non-Conformal Vision Enhancement Systems on Older Driver Performance, is included as an appendix to this report.Item Investigation the Effect on Driver Performance of Advanced Warning Flashers at Signalized Intersections(2001-07-01) Smith, Thomas J; Hammond, Curtis; Wade, Michael GThis report summarizes the findings of a human factors analysis to determine the effects of advanced warning flashers (AWFs) on simulated driving performance. The Minnesota Department of Transportation sponsored the project. Researchers used the flat-screen simulator at the University of Minnesota Human Factors Research Laboratory to conduct experiments. They measured vehicle speed, braking, and acceleration/deceleration during simulated driving and visually observed stopping behavior. In addition, they analyzed responses to a post-test questionnaire. They created a 11.3-mile simulated driving environment with 10 signalized intersections and configured four experimental models: low speed limit (SL) of 50 miles per hour with no AWFs, low SL with AWF at each intersection, high SL of 65 miles per hour with no AWFs, and high SL with AWF at each intersection Researchers set different vehicle-signal proximity intervals, with all green/no yellow as the control, and zero seconds with the vehicle adjacent to the signal, two seconds, three-and-a-half seconds, or five seconds. With each model, they assigned two intersections each proximity interval, with the sequence of intersection proximity intervals ordered differently for each model. Each of 24 subjects completed duplicate driving trials with each model. The study revealed that, relative to intersections with no AWFs, drivers who encountered yellow signals at AWFs intersections: stopped more frequently at low SLs but not at high SLs, drove more slowly while approaching intersections with two and three-and-a-half second proximity intervals, and displayed less inconsistent behavior at intersections with short proximity intervals. Researchers concluded that AWFs assist drivers with decision-making behavior and promote safer driving behavior. They recommended field research to study an actual environment.Item Reducing Risk Taking at Passive Railroad Crossings With Active Warnings(2004-06-04) Smith, Thomas JThis simulated driving study evaluates driver interaction with a low cost active warning system being considered by Mn/DOT for potential installation at passive highway-rail intersections (HRIs). The objective of the study is to ascertain if, relative to HRIs with passive signage, drivers interact in a more cautious manner with HRIs equipped with active warning system technology. The experimental design comprised: (1) 0.65 mi simulated roadway, with simulated HRI 0.644 km (0.4 mi) from start line; (2) 1 trial (start to end line) lasts about 1 min; (3) 120 trials/subject; (4) simulated train encountered in 13.3% of trials; (5) 25 subjects (Ss) (15 females, 10 males); (6) independent measures are: 4 control/test conditions; train absent/present; visibility clear/fog; (7) 2 control conditions: Control #1-advance passive warning sign (WS)/ crossing (Xing) passive WS; Control #2-advance passive WS/Xing active WS (flashing red lights); (8) 2 Test Conditions: Test #1-advance active WS (flashing yellow lights)/Xing active WS; Test #2-advance active flashing variable message sign (VMS)/Xing active WS; and (9) dependent measures are visually observed unsafe incidents and objective simulated driving measures (speed, braking, acceleration), plus responses to a post-test questionnaire (PTQ). Major results are: (1) statistically significant main effects of train (present/absent), visibility (clear/foggy), and Xing WS conditions; (2) incidents of vehicle beating train or hitting train are higher for trials with a passive advance WS, relative to those with an active advance WS; (3) with a train present and clear visibility, for all measurement intervals, active advance WS are associated with lower mean vehicle speeds, compared to mean speeds observed with passive advance WS; (4) active advance and Xing WS are perceived by PTQ respondents to be more usable and more conspicuous than passive advance and Xing WS ; and (5) flashing words (e.g., a VMS) are perceived by PTQ respondents to be more conspicuous than flashing lights on an active advance HRI WS.