Special conditions such as dark objects on asphalt pavement or automobiles with excessive windshield reflectances, e.g., cars No. 5, 35, 43, 45 and 55 (and no doubt others at certain sun positions) will produce very low contrasts.

While dirt on the windshield is, on the average, unimportant, certain notable exceptions were found (see cars 35, 39 and 56). It is known that tobacco smoke is hygroscopic, and smoke residues on the inside of the windshield will probably cause greater light scattering, at high atmospheric humidities, than noted here.

The figures 2 through 6 show various manufacturers' concepts of a modern space age automobile's control panel! It is apparent that standardization of basic controls, instruments and locations would be helpful and would remove this most critical visual area from the hands of the car stylist and permit life saving basic improvements. The numbers in each photo indicate areas corresponding to the luminances given in the figure legends. Fourteen to 20 measurements were made on each automobile dash panel and the sites chosen were marked on a transparent overlay of a photograph of the dash panel. The camera distance was about 1 meter from the speedometer in each case. The object marked S is a standard reflector used with the Spectra Brightness Spot Meter to determine the illuminance falling on the instrument panel. The photographs and brightness readings paint a clear picture. Figures 2 and 3 show cars number 5 and 34. While car No. 5 has nearly the lowest (12 ft. L.) instrument panel brightness of all tested, car No. 34 has nearly the highest. The author has driven a vehicle similar

Figure 3, Car No. 34. S is the standard reflector. The ft. L. luminance levels are: 1) 125; 2) 135; 3) 230; 4) 1700. Note the need to search "in the dark" below area 4) for control levers and knobs.

to No. 5 on a trip and the frustratingly long time required to adapt to the dark speedometer area was still further extended by the need to search for the meter needle which was even less visible. Car No. 34 is much better in this respect, since the speedometer dial is at 125 ft. L., however the extensive dash area immediately below is 1700 ft. L., a lumi nance ratio of over 13 to 1! Since task and surround luminance ratios 3 to 1 or less are considered desirable and since 10 to 1 is considered as the upper limit, it is apparent that serious seeing problems are present in these two cars.

Figure 4, Car No. 15. S is the standard reflector. The ft. L. luminance levels are: 1) 100; 2) 90; 3) 410; 4) 1600. At 3 the glass reflection has blocked out the speedometer numbers. The numbers are of a particularly low contrast on this model.

Figures 4, 5 and 6 show some of the variations in panel design characteristic of the industry. Note the extreme range of glare intensities in figure 5 and the brighter, more uniform appearance of the dash in figure 6. Even in the figure 6 the surround (3) is brighter than the dial themselves!

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Special conditions such as dark objects on asphalt pavement or automobiles with excessive windshield reflectances, e.g., cars No. 5, 35, 43, 45 and 55 (and no doubt others at certain sun positions) will produce very low contrasts.

While dirt on the windshield is, on the average, unimportant, certain notable exceptions were found (see cars 35, 39 and 56). It is known that tobacco smoke is hygroscopic, and smoke residues on the inside of the windshield will probably cause greater light scattering, at high atmospheric humidities, than noted here.

The figures 2 through 6 show various manufacturers' concepts of a modern space age automobile's control panel! It is apparent that standardization of basic controls, instruments and locations would be helpful and would remove this most critical visual area from the hands of the car stylist and permit life saving basic improvements. The numbers in each photo indicate areas corresponding to the luminances given in the figure legends. Fourteen to 20 measurements were made on each automobile dash panel and the sites chosen were marked on a transparent overlay of a photograph of the dash panel. The camera distance was about 1 meter from the speedometer in each case. The object marked S is a standard reflector used with the Spectra Brightness Spot Meter to determine the illuminance falling on the instrument panel.

The photographs and brightness readings paint a clear picture. Figures 2 and 3 show cars number 5 and 34. While car No. 5 has nearly the lowest (12 ft. L.) instrument panel brightness of all tested, car No. 34 has nearly the highest. The author has driven a vehicle similar

Figure 3, Car No. 34. S is the standard reflector. The ft. L. luminance

levels are: 1) 125; 2) 135; 3) 230; 4) 1700. Note the need to search "in the dark" below area 4) for control levers and knobs.

to No. 5 on a trip and the frustratingly long time required to adapt to the dark speedometer area was still further extended by the need to search for the meter needle which was even less visible. Car No. 34 is much better in this respect, since the speedometer dial is at 125 ft. L., however the extensive dash area immediately below is 1700 ft. L., a lumi nance ratio of over 13 to 1! Since task and surround luminance ratios 3 to 1 or less are considered desirable and since 10 to 1 is considered as the upper limit, it is apparent that serious seeing problems are present in these two cars.

Figure 4, Car No. 15. S is the standard reflector. The ft. L. luminance levels are: 1) 100; 2) 90; 3) 410; 4) 1600. At 3 the glass reflection has blocked out the speedometer numbers. The numbers are of a particularly low contrast on this model.

Figures 4, 5 and 6 show some of the variations in panel design characteristic of the industry. Note the extreme range of glare intensities in figure 5 and the brighter, more uniform appearance of the dash in figure 6. Even in the figure 6 the surround (3) is brighter than the dial themselves!

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Figure 5, Car No. 41. S is the standard reflector. The ft. L. luminance levels are: 1) 35; 2) 120; 3) 52; 4) 1000; 5) 26,000; 6) 2,500; 7) 380,000. Note the veiling glare at 2 and the poor contrast of labels on control knobs at lower left.

Figure 6, Car No. 40. S is the standard reflector. The ft. L. luminance levels are: 1) 100; 2) 150; 3) 175; 4) 7,200; 5) 38.