Abstract

The application of laboratory threshold visibility data to the subject of driving visibility with heat absorbing glass has been reviewed in an attempt to resolve excessive differences between calculated predictions and road test observations. New calculations are described that yield predicted losses of visibility distance due to the use of heat absorbing glass rather than regular glass in automobile windshields. The predicted losses agree satisfactorily with the observed losses for road tests, which average proximately 3%. The new calculations have made use of a revised visual exposure interval of ⅕ sec corresponding with five visual fixational pauses per second and a new simulation model that assumes that the target-to-background contrast increases with reduced headlamp-to-target distance.

© 1974 Optical Society of America

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References

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  1. W. Heath, D. M. Finch, Highway Res. Board Bull. 68, 1 (1953).
  2. V. J. Roper, Highway Res. Board Bull. 68, 16 (1953).
  3. H. C. Doane, G. M. Rassweiler, Highway Res. Board Bull. 127, 23 (1955).
  4. H. R. Blackwell, Highway Res. Board Bull. 89, 43 (1954).
  5. H. Haber, J. Opt. Soc. Am. 45, 413 (1955).
    [CrossRef] [PubMed]
  6. D. W. Dunipace, John Strong, M. Huizinga, Appl. Opt. 12, 1377 (1973).
    [CrossRef] [PubMed]
  7. H. R. Blackwell, J. Opt. Soc. Am. 36, 624 (1946).
    [CrossRef] [PubMed]
  8. H. R. Blackwell, Illum. Eng. 54, 317 (1959).
  9. H. R. Blackwell, Illum. Eng. 47, 602 (1952).
  10. H. R. Blackwell, J. H. Taylor, “Survey of Laboratory Studies of Visual Detection,” preprint of paper presented at the North Atlantic Treaty Organization Seminar on Detection, Recognition, and Identification of Line-of-Sight Targets (August 1969).
  11. J. H. Taylor, Appl. Opt. 3, 562 (1964).
  12. H. R. Blackwell, B. S. Pritchard, R. N. Schwab, Highway Res. Board Bull. 255, 117 (1960).
  13. S. Q. Duntley, Appl. Opt. 3, 551 (1964).
    [CrossRef]
  14. Data supplied by General Electric Company, Nela Park, Cleveland, Ohio.
  15. Data supplied by Westinghouse Electric Corporation, Bloomfield, New Jersey.
  16. R. W. Hull, R. H. Hemion, D. G. Cadena, B. C. Dial, DOT HS-800 529, PB 203 145 (July1971).

1973 (1)

1964 (2)

J. H. Taylor, Appl. Opt. 3, 562 (1964).

S. Q. Duntley, Appl. Opt. 3, 551 (1964).
[CrossRef]

1960 (1)

H. R. Blackwell, B. S. Pritchard, R. N. Schwab, Highway Res. Board Bull. 255, 117 (1960).

1959 (1)

H. R. Blackwell, Illum. Eng. 54, 317 (1959).

1955 (2)

H. C. Doane, G. M. Rassweiler, Highway Res. Board Bull. 127, 23 (1955).

H. Haber, J. Opt. Soc. Am. 45, 413 (1955).
[CrossRef] [PubMed]

1954 (1)

H. R. Blackwell, Highway Res. Board Bull. 89, 43 (1954).

1953 (2)

W. Heath, D. M. Finch, Highway Res. Board Bull. 68, 1 (1953).

V. J. Roper, Highway Res. Board Bull. 68, 16 (1953).

1952 (1)

H. R. Blackwell, Illum. Eng. 47, 602 (1952).

1946 (1)

Blackwell, H. R.

H. R. Blackwell, B. S. Pritchard, R. N. Schwab, Highway Res. Board Bull. 255, 117 (1960).

H. R. Blackwell, Illum. Eng. 54, 317 (1959).

H. R. Blackwell, Highway Res. Board Bull. 89, 43 (1954).

H. R. Blackwell, Illum. Eng. 47, 602 (1952).

H. R. Blackwell, J. Opt. Soc. Am. 36, 624 (1946).
[CrossRef] [PubMed]

H. R. Blackwell, J. H. Taylor, “Survey of Laboratory Studies of Visual Detection,” preprint of paper presented at the North Atlantic Treaty Organization Seminar on Detection, Recognition, and Identification of Line-of-Sight Targets (August 1969).

Cadena, D. G.

R. W. Hull, R. H. Hemion, D. G. Cadena, B. C. Dial, DOT HS-800 529, PB 203 145 (July1971).

Dial, B. C.

R. W. Hull, R. H. Hemion, D. G. Cadena, B. C. Dial, DOT HS-800 529, PB 203 145 (July1971).

Doane, H. C.

H. C. Doane, G. M. Rassweiler, Highway Res. Board Bull. 127, 23 (1955).

Dunipace, D. W.

Duntley, S. Q.

S. Q. Duntley, Appl. Opt. 3, 551 (1964).
[CrossRef]

Finch, D. M.

W. Heath, D. M. Finch, Highway Res. Board Bull. 68, 1 (1953).

Haber, H.

Heath, W.

W. Heath, D. M. Finch, Highway Res. Board Bull. 68, 1 (1953).

Hemion, R. H.

R. W. Hull, R. H. Hemion, D. G. Cadena, B. C. Dial, DOT HS-800 529, PB 203 145 (July1971).

Huizinga, M.

Hull, R. W.

R. W. Hull, R. H. Hemion, D. G. Cadena, B. C. Dial, DOT HS-800 529, PB 203 145 (July1971).

Pritchard, B. S.

H. R. Blackwell, B. S. Pritchard, R. N. Schwab, Highway Res. Board Bull. 255, 117 (1960).

Rassweiler, G. M.

H. C. Doane, G. M. Rassweiler, Highway Res. Board Bull. 127, 23 (1955).

Roper, V. J.

V. J. Roper, Highway Res. Board Bull. 68, 16 (1953).

Schwab, R. N.

H. R. Blackwell, B. S. Pritchard, R. N. Schwab, Highway Res. Board Bull. 255, 117 (1960).

Strong, John

Taylor, J. H.

J. H. Taylor, Appl. Opt. 3, 562 (1964).

H. R. Blackwell, J. H. Taylor, “Survey of Laboratory Studies of Visual Detection,” preprint of paper presented at the North Atlantic Treaty Organization Seminar on Detection, Recognition, and Identification of Line-of-Sight Targets (August 1969).

Appl. Opt. (3)

D. W. Dunipace, John Strong, M. Huizinga, Appl. Opt. 12, 1377 (1973).
[CrossRef] [PubMed]

S. Q. Duntley, Appl. Opt. 3, 551 (1964).
[CrossRef]

J. H. Taylor, Appl. Opt. 3, 562 (1964).

Highway Res. Board Bull. (5)

H. R. Blackwell, B. S. Pritchard, R. N. Schwab, Highway Res. Board Bull. 255, 117 (1960).

W. Heath, D. M. Finch, Highway Res. Board Bull. 68, 1 (1953).

V. J. Roper, Highway Res. Board Bull. 68, 16 (1953).

H. C. Doane, G. M. Rassweiler, Highway Res. Board Bull. 127, 23 (1955).

H. R. Blackwell, Highway Res. Board Bull. 89, 43 (1954).

Illum. Eng. (2)

H. R. Blackwell, Illum. Eng. 54, 317 (1959).

H. R. Blackwell, Illum. Eng. 47, 602 (1952).

J. Opt. Soc. Am. (2)

Other (4)

H. R. Blackwell, J. H. Taylor, “Survey of Laboratory Studies of Visual Detection,” preprint of paper presented at the North Atlantic Treaty Organization Seminar on Detection, Recognition, and Identification of Line-of-Sight Targets (August 1969).

Data supplied by General Electric Company, Nela Park, Cleveland, Ohio.

Data supplied by Westinghouse Electric Corporation, Bloomfield, New Jersey.

R. W. Hull, R. H. Hemion, D. G. Cadena, B. C. Dial, DOT HS-800 529, PB 203 145 (July1971).

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Figures (7)

Fig. 1
Fig. 1

Laboratory visibility data for a ⅕-sec exposure interval. The above ordinate scales: Laboratory Contrast is the threshold contrast observed in the laboratory and also the operational contrast for X = 1; Operational Contrast uses a factor of X = 30. In this figure, the different curves represent relationships for different size targets, however, the curves are labeled in terms of target area α2 rather than α. Luminance in cd/m2 is obtained by multiplying the value in ft-L by 3.43.

Fig. 2
Fig. 2

Operational visibility surface representing road test conditions, with e = ⅕ sec and X = 1. Line P1 P2 has been drawn parallel to the C axis through (α,T,C) = (15.3, 0.049, 0.01) for use in determining the contrast of a liminally visible target having α = 15.3 min and T = 0.049 ft-L. Luminance in cd/m2 is obtained by multiplying the value in ft-L by 3.43.

Fig. 3
Fig. 3

Operational visibility curves for road test conditions, with e = ⅕ sec and X = 1. To convert luminance units to cd/m2 multiply value in ft-L by 3.43.

Fig. 4
Fig. 4

Operational visibility curves for highway driving conditions, with e = ⅕ sec and X = 30. To convert luminance units to cd/m2 multiply value in ft-L by 3.43.

Fig. 5
Fig. 5

Illumination E(Z) produced by two GE-6012 headlamps. To convert target distance to meters, multiply value in feet by 0.305, and to convert illumination to lm/m2, multiply value in ft-cd by 10.76.

Fig. 6
Fig. 6

ISO-candela contours for the upper beam of a GE-6012 headlamp. REL—road edge from left lamp; RER—road edge from right lamp. Intensity in direction of maximum intensity is 32,400 cd. To convert target distance to meters, multiply value in feet by 0.305.

Fig. 7
Fig. 7

Enlarged section of Fig. 3 or Fig. 4. REF designates curves representing ISO-C and ISO-B operational curves shown in Fig. 3 or Fig. 4; the two curves through V3 are interpolations between adjacent REF curves.

Tables (2)

Tables Icon

Table I Sample Visibility Loss Predictions

Tables Icon

Table II Comparison of Calculated Visibility Losses and Road Test Observations

Equations (31)

Equations on this page are rendered with MathJax. Learn more.

C = ( T B ) / B .
α = 286.5 d / Z ,
T = E ( Z ) R .
Δ Z / Z G · ( F 1 ) ,
α t i ( T , C ) t i = α o i ( T , C ) t i , α t m ( T , C ) t m < α o m ( T , C ) t m , α t f ( T , C ) t f = α o f ( T , C ) t f .
Δ log α t = Δ log α o ,
Δ log α t = Δ log α t 1 + Δ log α t 2 ,
Δ log α o = Δ log α o 1 + Δ log α o 2 ,
Δ log α t 1 = 0.
Δ log α t 1 P 1 Δ log T t 1 + Q 1 Δ log C t 1 ,
Δ log α t 2 P 2 Δ log T t 2 .
Δ log α o 1 p Δ log T t 1 + q Δ log C t 1 ,
Δ log α o 1 p Δ log T t 1 .
Δ log α o 2 p Δ log T t 2 + q Δ log C t 2 .
Δ log C t 2 = 0.
C = ( T / B ) 1
d log C = 0.434 d C / C .
d log C = 0.434 d T / B C = ( T / B C ) d log T = [ ( C + 1 ) / C ] d log T .
Δ log C t 2 [ ( C + 1 ) / C ] d log T t 2 .
Δ log C t 2 m Δ log T t 2 ,
m = 0 ,
m = ( C + 1 ) / C .
Δ log α o 2 ( p + m q ) Δ log T t 2 .
Δ log α t P 2 Δ log T t 2 ,
Δ log α t p Δ log T t 1 + ( p + m q ) Δ log T t 2 .
Δ log α t [ P 2 p / ( P 2 p m q ) ] Δ log T t 1 .
Δ log α t G Δ log T t 1 ,
G = { | P 2 | | p | | P 2 | + | p | + m | q | } .
Δ log α = Δ log Z 0.434 Δ Z / Z ,
Δ log T t 1 0.434 Δ T / T = 0.434 ( F 1 ) .
Δ Z / Z G · ( F 1 ) .

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