Our protocol provides researcher a very adaptable platform and tools for investigating the benefits and the effectiveness of the application of tactile devices, especially for in-vehicle warning system. This vibrating toolkit provides a safe, inexpensive, and effective technique for investigating various kinds of driving-related research. This method can also be used to conduct other human behavioral studies.
This protocol has provided insight into the potential application of smart wearable devices in promoting driving safety. To configure the driving simulation software for an experiment, open the folder of the driving simulation software, the runtime folder, and the config folder. Open the expconfig.
txt file and make any adjustments to the default settings of the driving simulation as necessary, according to the experimental design. Configure the UDP settings if a UDP data transfer is required for the experiment, and use true or false to allow the timestamp data synchronization to a specific local network IP address, via the enableUDPSendData option, to determine whether to enable the UDP for data transfer. Then specify each section of the IP address using the commands as indicated, to define the IP address for the UDP transfer.
To set up the driving simulator, connect the steering wheel, three mounted projectors, and three projector screens to the computer. Place the projector screens 60 centimeters above the ground, and 22 centimeters away from the front of the instrumented vehicle Select options and display to set the screen resolution to match the screen size upon starting the driving simulation software. Then, on the configure page, select a player, and follow the instructions provided by the software, to calibrate the steering wheel, accelerator, and brake pedal.
To configure the vibrating toolkit, connect the toolkit to the power supply and switch on the toolkit. Connect the toolkit to the computer via Bluetooth, and complete a pilot skin sensitivity test, to define the vibrating frequency to be used for the experiment. Then use the codes as indicated to set the vibrating frequency to 70 Hertz, and to synchronize the brake events from the simulation software and vibrating toolkit.
To conduct a driving simulation experiment, after obtaining informed consent, help the participant adjust the seat distance to the pedal, and to set the back rest to a comfortable position. Inform the participant how to operate the simulator including the steering wheel, brake pedal, and accelerator pedal, and show the participant the roadmap that will be used for the driving simulation. Inform the participant that they should drive as they would in the real world while following the car in front of them and keeping a two second headway behind it, and instruct the participant to brake as soon as possible, Whenever the front vehicle brakes, even if the scenario does not require a brake response.
Have the participant complete a five-minute practice trial that includes a set of five random brakes to learn how to maintain a two second headway distance behind the front vehicle. During the practice trial, if the participant is between 2.25 to 2.5 seconds behind the front vehicle, the driving simulation software will play a prompt with a female voice saying, Too far, please speed up"Too far, please speed up. If the participant is less than 1.5 seconds behind the front vehicle, the driving simulation software will play a prompt with a female voice saying, Too close, please slow down"Too close, please slow down.
When the participant has completed the practice session, and can maintain a stable following distance, let the participant know that the study can be stopped without any penalty, by notifying the experimenters at any time as necessary. Inform the participant of the location that the vibrating toolkit will be placed before each block begins, and use medical tape to assist the participant in putting on the toolkit. Inform the participant that the toolkit will vibrate to warn the participant to brake, when the front vehicle is braking, and have the participant begin the first trial.
Give the participant a two minute rest upon the completion of each block to reduce any carry-over effects. When all of the trials have been completed, have the participant indicate their preference for, and the vibration intensity, at each location of the toolkit, on a scale of one to seven, and record the usage rate of each of the participant's daily wearable accessories. In this representative analysis, the driving simulation experiment took place in a bright environment, with the simulated scene designed to appear similar to driving on the highway on a clear day.
Post-talk analyses using pairwise Bonferroni-corrected T-tests, indicated no significant pairwise comparison differences in the brake response rates between task conditions. As illustrated, the application of tactile warnings could facilitate drivers'reactions towards upcoming hazards while driving, especially when the warning device was located on the driver's finger or wrist. Interestingly, while participants perceived the highest level of vibration in the temple area, the preference for the vibrating toolkit to be located at the temple area was the lowest.
In addition, the fact that over 50%of the participants wore a watch in their everyday life, suggests the feasibility of adopting wearable vibrotactile devices as a warning system in real life. Instead of performing the car-following task, researchers can perform an impact task to investigate the cognitive effects of tactile violence simply by activating the option in the protocol
