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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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  1. Greet participant.

  2. Record the time of their arrival on the debriefing sheet.

  3. Orient them to the vehicle.
    • Take participant to the vehicle parked outside the front door.
    • Check which vehicle they will do their first VES in and have them drive that vehicle if it is available.
    • Show them how to adjust their seat, interior display lights, the windshield wipers, and the steering wheel. Say: You will notice that your side and rearview mirrors have been covered. This is to reduce the glare that you might get from other vehicles.
    • Explain to them how to turn on and off the parking lights.
    • Make sure they are wearing their seatbelt.

  4. Turn on the baseline VES (HLB) for the drive to the road for the practice lap. Do not turn on the UV VES.
    • Turn on the power button to the power supply/converter unit. This is the lower of the two units located behind the driver's seat in each vehicle. The on/off switch is a small button. There are several red and green lights located near the on/off switch, and these lights will cycle on when the unit is switched on. The red lights will go dark if there are no problems on power up.
    • Turn the toggle switch on the upper unit on.
    • Follow these instructions to turn on power to each individual headlamp:
    • Locate the blue and cream colored on/off button box (with voltage output display) that controls the individual lights. This box is attached to the power supply/converter in the SUVs. Depress the appropriate red button corresponding to the desired light. The button will remain in the depressed position and light up red until depressed a second time to release the button and turn the light off.

  5. Make sure that you are wearing your seatbelt.

  6. Communicate to the onroad experimenter, and let him or her know that you are on your way to the road.

  7. Instruct the participant to drive to the Smart Road.

  8. Radio the control room to ask for the gate to be opened, and tell them the number of cars entering the road.

  9. The first vehicle will drive down to T3.

  10. Radio the relay station to let them know that you are driving down.

  11. The second vehicle will park at the entrance of T2 and wait for the relay station to say that the participant can come down.

  12. Orient participant to Smart Road

    First we will drive down the road to get you used to the road and the vehicle. Go ahead and drive down the road at 10 miles per hour. It is very important for your safety, and the safety of the experimenters on the road that you slow down to 10 mph or slower when we reach the section of road with snow on it.

    The in-vehicle experimenter is responsible for:
    • Allowing the participant to drive down the road.
    • Giving permission to the second vehicle to begin after receiving notification that the first vehicle is at T3.
    • Reminding the participant of the speed limit if necessary.
    • Telling the participant to start slowing down as soon as he or she can see the snow, so he or she can make a smooth entrance at 16.1 km/h (10 mi/h) or slower.

    First vehicle at T3
    • Pull all the way to the farthest parking space.
    • Put the vehicle in park and have the participant take their foot off the brake.
    • Have the participant turn off the parking lights.
    • Radio the relay station that the second vehicle can drive down.
    • Wait for valet to clean the headlights and completely move away from vehicle, prior to heading back up the hill.

    The instructions for the participant in the second vehicle at the bottom of the hill are to:
    • Pull into the nearest parking space.
    • Put the vehicle in park and take your foot off the brake.
    • Let the valet clean the headlights.

  13. Review instructions with the participant. This may be done while waiting at T2 or T3 during the practice drive:
    • Show the participant the button.
    • Read the following instructions:

    I will need you to hold this in your hand during the study. When you press this you will hear a beep. Once the study begins I need you to press the button as soon as you detect an object.

    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.

    When you can accurately recognize an object, I would like you to press the push button again and recognize the object verbally at the same time.

    Recognition is when you not only know something is there but you also know what it is.

    You will need to be specific when you recognize. If you see an object, you will need to tell me what the object is. For example, say "I see a person" or "I see a cyclist"

    If you perform an unsuccessful recognition, you can press the push button again and then verbally recognize the object.

  14. Hand the button to the participant.

  15. After both vehicles are at T3, radio the onroad experimenters that you are ready to begin.

  16. Allow the participant to do a practice run down the Smart Road. Say to the participant:
    We will now practice while you drive down the hill to help you get used to driving the vehicle on the Smart Road and using the buttons. I would like you to drive at 10 miles per hour or less (we don't want the speed dial to go over the 10 miles per hour mark at any point).

  17. Remind the participant how to identify the different objects. Say to the participant: On the way down we will practice how to detect and recognize objects. You will see two objects. Please remember to say "I see a person" or "I see a cyclist." If you perform an unsuccessful recognition, you can press the button again and orally identify the object.

  18. Make the following checks:
    • Check power supply/inverter of the laptop is connected to the black box and the back of the laptop. A green light on the inverter means that it is connected. If it is not connected, you might run out of power in the middle of the experiment and lose data.
    • Make sure the cable that inputs data to the computer is screwed all the way in.
    • Check that the button with the yellow sticker is on the Velcro.
    • Turn laptop power on.
    • Enter participant number, age, gender, weather condition, target order, and VES.
    • Start the computer program.
    It is very important that you do not talk to the drivers when you are collecting data, emergencies excluded.

  19. Monitor the computer while going up the hill. Follow these instructions:
    • Make sure that the value in the "Current Distance" field is increasing. This ensures the program is working.
    • When the participant presses the button the first time, the computer should beep and record the "Detection Dist."
    • After the participant presses the button the second time, the computer should beep and record the "Recognize Dist."
    • Press the keyboard spacebar when your body is in line with the object. After pressing the keyboard spacebar, the arrow will scroll down to the next object.
    • Press the keyboard ESC key if the participant presses the button by accident or states that he or she made a false detection.
    • Press the keyboard ESC key if the participant makes an unsuccessful recognition.
    • After you are aligned with the object, press the keyboard spacebar to reflect the distance of the object.

  20. During the practice run, you may need to assist the participant. For example, if he or she does not indicate the detection or recognition points, and the object is within nearly 12.19 m (40 ft), say to the participant: We are very close to the first object, please press the button as soon as you can detect it and then again when you can identify it.

  21. Monitor the safety of the pedestrians on the road
    • Use the computer program to determine when you are approaching a pedestrian.
    • Say "Station X, Clear" as soon as the participant identifies the pedestrian.
    • If driver does not see pedestrian, use the computer readout to determine when the vehicle is within 40 ft of pedestrian. Tell the pedestrian to clear at that time.
    • Make sure the participant is not driving over 10 mph They should be driving under 10 mph. This could be verified using the computer read out.
    • The screen starts flashing when the vehicle is (40 ft) from the station. If there is a pedestrian at the station, say into the radio "Station # XX-Clear" as soon as the screen starts flashing.
    • If you forget to press the keyboard spacebar, the program will go to the next station 50 feet after it passes the station. Please make a note on the error sheet, so the person working with the data can subtract the 50 feet from the station location recorded in the program.

  22. Pull into the turnaround and follow these directions:
    First car at T2:
    • Pull into the turn around and keep to the right side of the road. Park at the cone so that you are on the road side of the turnaround, facing up the hill, and parallel to the road.
    • As soon as the first car gets out of the snow, notify the second vehicle that it can proceed up the road.
    Second car at T2:
    • Pull up to the cone on the left side of the turnaround.
    • Wait until the first car is out of sight before going down the road.

  23. Lead experimenter will radio the snowplow operator when both vehicles have reached T2.

  24. Ask Driver the Questions about the VES
    • You may begin to ask the questions when the driver is past the snow, if you are comfortable doing so. If not, wait until they are parked.
    • Remind subjects of the scale, where 1 is strongly agree and 7 is strongly disagree.

  25. Document any unexpected events that occurred during the previous run on the In-vehicle Note Sheet.

  26. Show them to their next vehicle as per the order sheet
    • Ask the participant to leave the vehicle running and make sure it is in park.
    • Turn off the HID or HLB lights.
    • Assist driver in getting out of the vehicle if necessary.
    • Use the stepstools if necessary.
    • Lead/Guide participant from one vehicle to the next-if there are vehicles with lights on, take the participant around the back of the vehicle.
    • Open the door for the participant and move the seat back before he or she gets in.

  27. Orient the participant to the next vehicle and turn on the lights. Follow these instructions:
    • If the participant has been in the vehicle before, ask if he or she remembers the controls. Be sure to offer to answer questions.
    • Be sure to turn on the lights yourself and show the participant where to turn off the parking lights.
    • Turn on UV lights as soon as you get in the vehicle to allow them time to warm up before data collection.
    • Explain to the participant where the dimmer switch is.
    • Remind the participant to keep his or her seatbelt on at all times.
    • Ask the participant if he or she has any questions.
    • Hand the participant the keys and ask him or her to start the car.
    • Follow the orientation instructions for the appropriate vehicle listed below.

    White SUVs and large SUV:
    • Button on left side of seat moves seat up and down, back and forth (show button).
    • Lever on steering column moves the wheel up and down.
    • Turn on the parking lights (one click only).
    • Show the participant how to adjust the interior lights. If necessary, help him or her to adjust it by asking him or her to tell you when it is comfortable.

  28. Prepare for the first VES
    • Let the valet check the headlamps
    • Radio the onroad experimenters when you are ready to go down
    • Continue down the road.

    Start data collection for first VES when you are parallel with the guardrail.

  29. Monitor the safety of the pedestrians on the road.
    • Use the computer program to determine when you are approaching a pedestrian.
    • Say "Station X, Clear" as soon as the participant identifies the pedestrian.
    • If driver does not see the pedestrian, use the computer readout to determine when the vehicle is within 12.19 m (40 ft) of the pedestrian. Use the radio to tell the pedestrian to clear at that time.
    • Make sure the participant is not driving faster than 16.1 km/h (10 mi/h).

  30. Continue the same procedure for the remainder of the VES tests.

  31. Take the participants and in-vehicle experimenters from both vehicles back to the building in the large SUV.

  32. Document the time on the participant's debriefing sheet.
    • Ask the participant to fill out the payment receipt log.
    • Pay the participant, and thank him or her for participating.


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