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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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  • The primary goal of this research effort is safety. For that reason, you need to be safe at all times.
  • Drive in a safe manner at all times. This means observing the 25 mi/h speed limit on the road and 10 mi/h if the snowmaking has started, or if there is snow on the road.
  • Use a spotter when moving vehicles in and out of the garage.
  • Wear closed-toe shoes at all times.
  • Wear dark clothes and dark shoes.
  • Always wear your vest on the road.
  • Do not travel with the tailgate open.
  • Wear your safety glasses when you are exposed to headlights.
  • Always drive with your lights on.
  • If equipment breaks, tell the lead experimenter as soon as possible.
  • Attend the nightly meeting.

Each night, you need to arrive at [contractor facility] on time. The nightly meeting will cover topics such as protocol changes, problems from the previous night, and schedule concerns. Make sure you document any problems from the previous night.

Operations of the headlights are outlined with a diagram and description in each vehicle. Failure to follow the procedures will prevent the headlights from working, and leave gaps in the data. For this reason, you are to review the operations each night for your assigned vehicle.

While the study is being conducted, radio communications on channel 8 need to be minimized (emergencies excluded). Note that the in-vehicle experimenters cannot always respond to questions if they are interacting with the participant at that time. For this reason, you will need to give the in-vehicle experimenters extra time to reply.


Onroad experimenters are expected to:
  • Attend nightly meeting
  • Review changes in protocol
  • Lead experimenter will distribute the following forms:
    • Vehicle and road prep sheets to the valets.
    • Lead valet vehicle checklist.
    • Participant eye measurement sheets to valets.
    • VES order sheets with VES diagram to valets.
    • Object order to onroad experimenters.
Onroad experimenters are responsible for obtaining the following equipment:
  • A radio prepared in a plastic bag along with extension if desired.
  • Vest.
  • Flash light.
  • Safety glasses.
The valets are responsible for preparing the vehicles each night. However, onroad experimenters will need to assist them with this if they have any down time. Valets are to:
  • Put on vests.
  • Load nine cones into pickup to be placed at the turnarounds when you reach the road. Five will be dropped at the first turnaround and four at the bottom turnaround.
  • Place the tarps that will be used to cover the seat in one of the SUVs.
  • Park two SUVs at the front of the building for the participants
  • Transport the onroad personnel to the road using the pickup (Valet #2) – stations 2 and 4, and the large SUV (lead valet) – stations 1 and 5.
  • The lead valet is in charge of moving the generator cart from either the garage or the road storage container. This can be towed by the large SUV, SUV 2, and the pickup. At no point is the generator to be driven through the snow. It must be left at the turnaround before the onroad personnel are dropped off. The generator must not be driven faster than 32.19 km/h (20 mi/h).
  • The valets will be responsible for setting up the parking locations at each turnaround. The onroad personnel will be asked to help with the setup in each case.
  • Set up parking spaces by putting out the cones at the appropriate locations.
  • Set up cones at the entrance and exit points of both turnarounds.
  • Make sure all cones and objects on the road that are not part of the ENV study are removed from the road.
  • Receive nightly assignment to one of the following locations:
    • Stations 1 and 5.
    • Stations 2 and 4.
  • Before getting to your station, double check to make sure you have all of the necessary items.
  • Wear a radio at all times. Either hold it or attach it to your clothing. Also, make sure one of your radios is set to channel 8.
  • In an emergency, immediately radio the relay station experimenter. The relay station experimenter will make sure the in-vehicle experimenters heard the message.
  • As the trials progress, make sure you are ready in the proper position before the experimental vehicle gets to your station and clear the location before the vehicle comes back up the road. Also make sure you are hidden if you are not the designated object.
  • Use the radio to indicate your station and where the snow has the greatest concentration, such as "Station X–Guardrail," and "Station Y–Other." Wind affects where the snow is falling such as toward the guardrail or to the side opposed to the guardrail. The experimental vehicle will always drive on the center of the road.


Drivers will be oriented to the road by driving down the hill. During this time onroad experimenters are to remain hidden. However, on the way up the hill, the following stations will need to present objects:

Station 4: Perpendicular Pedestrian, White Clothing.
Station 5: Parallel Pedestrian, White Clothing.

In-vehicle experimenters will assume that all stations are ready, unless an onroad experimenter radios to say otherwise. Below is a table of the objects and their placement locations. These locations assume that the vehicle is driving in the middle of the roadway. If the objects need to be shifted toward the guardrail or the other side, move the locations accordingly.

Perpendicular black pedestrian Straight (perpendicular) line between center of each lane Wear black clothing. Walk from the center of the lane on the passenger side of the vehicle to the center of the other lane and back. Repeat.
Perpendicular white pedestrian Straight (perpendicular) line between center of each lane Wear white clothing. Walk from the center of the lane on the passenger side of the vehicle to the center of the other lane and back. Repeat.
Parallel white pedestrian In middle of lane on passenger side of vehicle Wear white clothing. Walk ten paces towards the vehicle, then ten paces back. Be sure you are always facing the vehicle. Repeat
Blank None Remain out of view.
  • After the first lap, onroad experimenters are to begin as indicated on object order sheets. The in-vehicle experimenters will indicate when the object trials begin.
  • Onroad experimenters need to be out of view of the participants if they are not listed on the order sheet for that run.
  • Put safety glasses on.
  • Safety Note: Experimental vehicles are not to come within 40 feet of a mobile object on the roadway. Also, the in-vehicle experimenters will ask you to "clear" once they have detected you, or if they are close to the safety margin. In that case, you can clear as soon as you hear "Station X - Clear." However, if you do not feel safe at any point in time you must clear your position.
  • After you step off the road, maintain your position on the shoulder. This will allow the in-vehicle experimenters to record the distances of detection and recognition on the distance measuring devices.
  • This methodology will be repeated for all four VES configurations. If there will be two sessions that night, the valet will drive around and collect the onroad experimenters to provide a break. You will return to the road after your break and set up for the second session that will begin shortly. If there is only one session that night, the valets will drive around and collect all experimenters and cones after the fourth configuration.
  • If you notice any problems or mistakes occurring during the night, record them on the vehicle preparation sheets.


  • If a double or a triple experiment is being run on a particular night. The onroad people will be given a break between subjects. Valet number 1 will use SUV2 to take the ambient light measurements.
  • The two SUVs will be returned to the front entranceway of the building for the next subjects.
  • The onroad people will be returned to the road by the Large SUV and the pickup as before.


  • Gather all experimental equipment and return to the building.
  • Valet #2 will collect cones from the turnarounds and carry them in the pickup.
  • Check the gas level of each vehicle.
  • Return SUVs to the garage-use spotter when pulling into the bay.
  • Put dirty scrubs in the bin.
  • Note any vehicle problems on the vehicle preparation sheets.
  • Return the radios (personal and in-vehicle).
  • Sign radios back in. Make sure all radios that have been checked out are returned at the end of the night.
  • Make sure the power is off when you put the radios into the charger. If not they won't charge.
  • Submit paperwork to in-vehicle experimenter.


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