Cal. Code Regs. tit. 13, § 743
The luminous intensity of a rear fog tail lamp tested as specified in Article 4 of this subchapter shall be as shown in Table I.
TABLE I. PHOTOMETRIC REQUIREMENTS FOR FOG TAILLAMPS
Test point coordinates
Cd
Vertical
Horizontal
Min
10L
10
10U & 10D
V
25
10R
10
20L
10
10L
30
5L
50
5U & 5D
V
70
5R
50
10R
30
20R
10
20L
15
10L
40
5L
80
H
V
80
5R
80
10R
40
20R
15
Note: The maximum candlepower shall not exceed 300 cd over any area larger than that generated by an 0.25 deg radius.
Note: Authority cited: Section 26103, Vehicle Code. Reference: Sections 24012 and 26103, Vehicle Code.
1. Amendment of Table I filed 12-17-81; effective thirtieth day thereafter (Register 81, No. 51).