U.S. Department of Transportation
Federal Highway Administration
1200 New Jersey Avenue, SE
Washington, DC 20590

Skip to content
Facebook iconYouTube iconTwitter iconFlickr iconLinkedInInstagram

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-04-137
Date: December 2005

Enhanced Night Visibility Series, Volume VI: Phase II—Study 4: Visual Performance During Nighttime Driving in Fog

PDF Version (1.27 MB)

PDF files can be viewed with the Acrobat® Reader®


Back Seat Experimenter’s Protocol Fog

Set Up

Setting up the computers.

One back seat experimenter should set up the Sedan first since they need it for training.

The other back seat experimenter should set up the SUV 3 first since they need it on the road.

Put a computer in appropriate car and plug in power supply and serial cable (may need to use small screwdriver for some).

Turn on each computer (leave at C:\Fog).

Retrieve all four visibility computers and set up as follows:

Visibility computer setup.

Ensure that the computer is plugged into the electrical adapter and that the serial cable from the [Konica] Minolta Meter is plugged into the 9 pin serial port on the computer.

Turn on the computer.

Turn on the [Konica] Minolta Meter. In all vehicles but the SUV 3, the switch for the meter is on the top of the meter which is mounted on the windshield of the vehicle. In the SUV 3, the meter is on the floor behind the driver’s seat. After turning on the meter, make sure that the instrument is working by viewing it through the windshield. The number should change if you place your hand over the detector on the outside. If the instrument does not turn on, the batteries are likely dead and need to be replaced (See “Changing the meter batteries” at the bottom of the protocol). If the numbers do not change, the measurement hold button is likely pressed and needs to be released. The hold button is on the top of the meter and needs to be pushed to release it.

On the computer, start the [Konica] Minolta software using START\Programs\T-A30\dmsta30 (or use the shortcut on the desktop to “dmsta30”).

The software will start and will start looking for the meter. If an error occurs and the software asks if the software should be run in offline mode then the communications to the meter have failed and you should check the cable and that the meter is turned on.

If the connection is working, the software should show a list of numbers 1 through 32 with boxes beside them. In all vehicles but the SUV 3, make sure that box zero says OK. In the SUV 3, Box 1 should say OK. If it does not, check the cabling again.

Changing the meter batteries.

There are spare batteries in an envelope in the glove box of each vehicle.

The meter is attached to the mounting plate using Velcro and a thumb screw. Loosen the thumb screw and then pull the instrument from the Velcro.

You might have to remove the cable from the instrument.

Remove the battery cover and replace with 2 AA batteries. You might have to pull the Velcro back from the edge to release the battery cover.

Remount the battery cover, smoothing out the Velcro if required.

Reattach with the thumbscrew first and then with the Velcro.

Tighten the thumbscrew and reattach cable if required

Data Collection

Visibility Computer Operation.

At the start of each run, open a new file in the [Konica] Minolta Software using File\New. The software will ask two questions: 1) Would you like to open a new file? Answer “YES”,

2) Measurement type? Answer “OK” to the defaults presented.

Press the green arrow button in the software to start the measurement. The software will ask if you would like to start a measurement and answer “YES”.

Record the data number at the start of the run (when the vehicle leaves the turnaround).

During the run, record the data number at the time when the observer detects the object. Also record the lux reading that corresponds with that data number.

Record the data number when the vehicle arrives at the next turnaround.

At the end of the run, press the green box button to stop the measurement, and save the file.

Close the file once it has been saved. Then open a new one by clicking on the new file icon (the blank sheet) at the top left on the toolbar.

Repeat procedure for each run.

Taking Notes.

On the “Back Seat Experimenter Notes Sheet” you will need to record the following information for each run:

Data number that corresponds to the time of departure from turnaround (described above).

Windshield wiper speed during run (low, medium or high).

The data number when the subject sees the object (described above).

The lux reading when the participant sees the object (described above).

Any additional information that you can gather about the fog (too thick, too thin, whether you can see the second object from the first station, etc.).

Time of arrival at the next turnaround (described above).


Previous    Table of Contents    Next
Federal Highway Administration | 1200 New Jersey Avenue, SE | Washington, DC 20590 | 202-366-4000
Turner-Fairbank Highway Research Center | 6300 Georgetown Pike | McLean, VA | 22101