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Federal Highway Administration Research and Technology
Coordinating, Developing, and Delivering Highway Transportation Innovations

This report is an archived publication and may contain dated technical, contact, and link information
Publication Number: FHWA-HRT-04-136
Date: December 2005

Enhanced Night Visibility, Volume V: Phase II—Study 3: Visual Performance During Nighttime Driving in Snow

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Protocol for Enhanced Night Visibility–SNOW

In-Vehicle Experimenters Training

  1. Prior to the participants' arrival, make sure that all the needed forms are available.

  2. Set up the conference room.
    • Close all the shades.
    • Turn on all overhead lights.
    • Turn off halogen lamps.
    • Position work light for vision contrast by placing it within the tape on the floor.
    • Get color vision test, eye occluder, alcohol and cotton balls from prep room.

  3. Greet participant.

  4. Record the time that the participant arrived on the debriefing form.

  5. Show driver's license.

    Before we begin, it is required for me to verify that you have a driver's license. Would you please show me your license?

    Must be a valid Class A driver's license to proceed with the study. Out of State is fine.

    Experimenter reads all text in italics aloud to each participant:

    This research is sponsored by the Federal Highway Administration. The purpose is to gather information that will be available to the public, including car manufacturers. The goal is to determine the best vision enhancement systems to help drivers see objects and pavement markings at night.

    This study will involve you filling out some forms now and then driving different cars on the Smart Road. The entire study will take approximately 3 hours. We will pay you 20 dollars per hour. The total amount will be given to you at the end of the third session

    The study will take place on the Smart Road testing facility. The road will be closed off to all traffic except for experimental vehicles. There will be, at most, two experimental vehicles on the road at one time, including the vehicle you will be in.

    During the study, an experimenter will be in the vehicle with you at all times. The experimenter will be responsible for asking you questions during the drive, recording some data, and monitoring the equipment. In addition, he or she will be able to answer any questions you have during the drive.

    You will be exposed to four different vision enhancement systems. You will make one lap on the Smart Road for each vision enhancement system. On these laps you will be exposed to several objects. Your job will be to tell me when you are able to detect the object and when you are able to recognize what the object is.

    Do you have any questions at this time?
    (Answer questions if needed).

  6. Informed consent.

    Now I have some paperwork for you to fill out. This first form tells you about the study, what your job is, and any safety risks involved in the study. Please read through the document. If you have any questions, please feel free to ask. If not, please sign and date the paper on the last page.

    • Give the participant the form.
    • Answer questions.
    • Have participant sign and date both forms.
    • Give the participant a copy of the informed consent.

  7. Tax forms.

    To complete the W-9, the participant must fill out the following in the box:

    • Name.
    • Address.
    • Tax ID number (social security number).
    • Sign and date at the bottom.

  8. Vision tests.

    Follow me and I will go through the vision tests with you.

    The results for all three parts must be recorded on the vision test form.

    The first test is the Snellen eye chart test.

    • Take the participant over to the eye chart test area.
    • Line up their toes to the line on the floor (20 feet).
    • Participants can leave on their glasses if they wear them for driving.
    Procedure: Look at the wall and read aloud the smallest line you can comfortably read.
    • If the participant gets every letter on the first line they try correct have them try the next smaller line. Continue until they miss a letter. At that time, record the one that they were able to read in full (line above).
    • If they get the first line they attempt incorrect, have them read the previous line. Repeat as needed until they get one line completely correct. Record this acuity.
    • Participant must have 20/40 or better vision using both eyes to participate in the study.

    The next vision test is the contrast sensitivity test. Take the participant over to the eye chart test area

    • Line up their toes to the line on the floor (10 feet).
    • Participants can leave on their glasses if they wear them for driving.
    Procedure: We are going to test how well you see bars at different levels of contrast. Your ability to see these bars relate to how well you see everyday objects. It is VERY IMPORTANT you do not squint or lean forward while you are taking the test.
    • Point out the sample patches at the bottom of the chart with the three possible responses (left, right, or straight).
    • Cover one eye with an occluder. (DO NOT let the participant use his/her hand to cover the eye since pressure on the eye may cause erroneous contrast sensitivity test results).
    • Instruct the participant to begin with Row A and look across from left to right. Ask the participant to identify the last patch in which lines can be seen and tell you which direction they tilt. If the response is incorrect, have the participant describe the preceding patch.
    • Use the table in the ENV binder to determine if subjects' answers are correct.
    • Each vertical column of numbers on the second part of the vision test form corresponds to a horizontal row on the chart. Record the last patch the participant correctly identifies in each row by marking the corresponding dot on the form.
    • To form the participant's contrast sensitivity curve, connect the points marked.
    • Cover the other eye and repeat all the steps above.

    The last vision test is the test for color blindness.

    • Take the participant back to his/her desk.
    • Place the book containing the plates on the testing apparatus.

    Please hold the red end of this handle to your nose and read the number on the following plates.

    • Record the participant's answers on the vision test form.

  9. ENV training.

    Have the participant sit at the table. Explain the following:

    The following presentation will provide instructions, definitions, and examples of the objects we will be using. You can ask me questions at any time. There will be some pages I will place extra emphasis on. Any questions before we begin the presentation?

    Answer questions as needed. Once there are no more questions, begin the instructions. Stress the following points:

    • Definition of detection versus recognition.
    • Stress safety (i.e. 10 miles per hour, drive safely, etc).
    • Again, answer questions.

    Slide 1: This study is called Enhanced Night Visibility given that its purpose is to evaluate vision enhancement systems.

    Slide 2: This is a timeline of how the night will break down. We are in the laboratory training portion right now.

    Slide 3: The Enhanced Night Visibility project is an extensive research project to determine what vision enhancement system configuration will best help people see objects on the road at night.

    We needed people to give us information on visibility and preference of the different vision enhancement systems. That is why you were asked to come here tonight. The information you give us will be compiled with other people's data so we can determine the best configuration.

    We will be using three different vehicles during the onroad study. All three vehicles are sport utility vehicles. The onroad portion will take place out on the Smart Road once it is completely dark. You will be performing the study in a snow condition.

    Slide 4: We are going through this training to make you more comfortable with the study before we begin driving. We will cover the items mentioned on this slide. I want to stress that if you have any questions, please stop and ask at any time.

    Slide 5: The Smart Road is perfect for testing of this type. It is completely closed off, making it safe for both drivers and experimenters.

    Slide 6: This is a picture of part of the Smart Road during daytime.

    Slide 7: Each vehicle might include more than one configuration of Vision Enhancement Systems for a total of 4 different configurations. All of the Vision Enhancement Systems are different headlight systems.

    Slide 8: Your primary responsibility is to drive safely. We are also interested in how far away drivers can detect and recognize objects along the road with these vision enhancement systems. We will explain what we mean by detection and recognition shortly. However, I would like to show you this.

    **Show them the button**

    I will ask you to hold a button like this during the study in your hand while driving. You will press the button like this.

    **Press the button**

    When you press this in the car, you will hear a beep.

    Slide 9: Detection is when you can just tell that something is on the road in front of you. You cannot tell what the object is but you know something is there. Detection is important while driving since it prepares you to possibly make an evasive action. As soon as you detect an object, please press the push button.

    Slide 10: Recognition is when you not only know something is there but you also know what it is. This is important to help you decide how best to avoid the object. For instance, if you see an object in the road and then realize it is a dog, you know that the object can move unpredictably and you need to slow down greatly and likely swerve to avoid it. If, however, you see an object and it is a box, you know the object is not likely to move, and slowing down a little and swerving will likely be sufficient.

    When you can accurately recognize an object, I would like you to press the push button and identify the object verbally at the same time. You will need to be specific when you identify. If you see an object, you will need to tell me what the object is.

    For example,

    “I see a person”

    “I see a cyclist”

    If you perform an unsuccessful recognition, you can press the button again.

    Slide 11: The objects that we will present you are pedestrians and cyclists. The pedestrians will be people walking across or along the road.

    Slide 12: Here are pictures of a couple of the objects. They will not look exactly like this in the road, since these were taken inside with the lights on. However, this should give you a good idea of what they will look like.

    Slide 13: We will also have some questionnaires for you to complete. As soon as you are done with a vision enhancement system, you will evaluate it. Therefore, after you see the objects with each VES, I will ask you this series of questions (show questionnaire). For each question, we want you to rank your answer on a scale from 1 to 7. One means you strongly agree with the statement. Seven means you strongly disagree with the statement. You can give me any number between 1 and 7. Your answers may or may not be different for each VES; we just want your opinion on the one you just saw.

    Here is the questionnaire that you will be answering for each VES. Let's go over each of the statements. Please, feel free to stop me at anytime, and ask as many questions as you want. (Read and explain each statement.)

    Slide 14: Go over main points.

    Slide 15: Do you have any questions about this questionnaire?
    Answer any questions.


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