This page gives access to the results of the second study (Test 2) in which 25 human subjects experienced a virtual jet ski ride. Each ride was recorded in a log file. As in Test 1, each log file contains the time history of handlebar position, throttle position, speed, and position on the lake. In addition, collision events and pop-up times for pop-up items are recorded.

As in Test 1, the Virtual Reality Modeling Language (VRML) is used to present the large data sets. For details see the comments in Test 1.

Tabulated Results

Summary of information about the 25 human subjects and related tabulated data:

Download Excel File Table2.xls

Legend

Interactive VRML Graphs


Sample Graph (screen copy from interactive VRML application):

enlarge

The Time Slider at the bottom allows to move the graph to the left and to the right. The current time (shown in seconds) corresponds to the position of the vertical black line crossing the graph. The ball in the map on top idicates the current position of the jet ski on the lake and moves with the Time Slider.

The zoom and compress buttons control overall viewing options.

The speed, throttle, and handlebar buttons toggle the display of the corresponding curve off/on.

The Speed Curve is shown in blue. The range is from 0 mph (horizontal black line at bottom) to 40 mph (blue line at top). Occasionally, the speed may exceed 40 mph.

The Throttle Position is shown in red and ranges from 0 (no throttle, black line) to 1 (full throttle, red line).

The Handlebar Position is shown in green. The range is from -1 (black line) to +1 (red line). A horizontal white line indicates the zero-position (going straight).

The graph shows time markers indicating collisions (white boxes) as well as the moments in time when certain pop-up items are created in the scene (colored boxes).

White Boxes indicate collisions as follows:

0 = collision with pop-up Log (near log or far log)
2 = collision with crossing pop-up Jet Ski (from the right or behind)
4 = collision with circling Yacht
5 = collision with circling Pontoon Boat
6 = collision with circling Jet Ski
7 = collision with pop-up Pontoon Boat in canal

Colored Boxes mark the time when a pop-up item is created:
0 = far Log pops up at 30 meters ahead (dark blue)
1 = near Log pops up at 20 meters ahead (light blue)
2 = crossing Jet Ski from the right pops up (dark green)
3 = crossing Jet Ski from behind pops up (light green)

Note that a collision with the Log or the crossing Jet Ski (white boxes 0 or 2) is always preceded by one of the four pop-up events (colored boxes 0, 1, 2, or 3).

The following links (Subject #nn) point to VRML files and require that the CosmoPlayer VRML plug-in is installed.

Note: In Test 2, subjects were allowed to explore the lake on their own pace, choose any path they like, and spend as much time as they wanted. As a result, the average ride lasted 13 minutes with a wide range from 4 minutes (min) to 36 minutes (max).


• Subject #21 -- Duration: 923.475 sec

• Subject #22 -- Duration: 959.893 sec

• Subject #23 -- Duration: 772.783 sec

• Subject #24 -- Duration: 237.053 sec

• Subject #25 -- Duration: 297.608 sec

• Subject #26 -- Duration: 762.091 sec

• Subject #27 -- Duration: 499.719 sec

• Subject #28 -- Duration: 488.173 sec

• Subject #29 -- Duration: 379.321 sec

• Subject #30 -- Duration: 565.472 sec

• Subject #40 -- Duration: 307.318 sec

• Subject #41 -- Duration: 311.562 sec

• Subject #42 -- Duration: 527.570 sec

• Subject #43 -- Duration: 2,165.853 sec

• Subject #44 -- Duration: 613.685 sec

• Subject #50 -- Duration: 916.118 sec

• Subject #51 -- Duration: 959.448 sec

• Subject #52 -- Duration: 939.091 sec

• Subject #53 -- Duration: 962.865 sec

• Subject #54 -- Duration: 866.947 sec

• Subject #55 -- Duration: 609.668 sec

• Subject #56 -- Duration: 925.180 sec

• Subject #57 -- Duration: 861.671 sec

• Subject #58 -- Duration: 905.429 sec

• Subject #59 -- Duration: 892.890 sec

Statistics of Individual Rides

The following series of graphs show selected statistical data obtained by analyzing the individual rides. Each graph shows the same data item(s) for each of the 25 subjects.

The spreadsheet used to create these graphs can also be downloaded as Excel file stats2.xls.

		Time spent at various speed ranges
		Percentage of time spent at various speed ranges
		Average change in Handlebars
		Standard Deviation of Handlebars
		Average Throttle position
		Standard Deviation of Throttle
		Number of Large throttle changes
		Poor Turning: Percent of time spent with throttle off and handlebars off center