= (Vs / Vm)2Sm
where:
Sc = Corrected braking distance,
Vs = Specified test velocity.
Vm = Measured test velocity,
Sm = Measured braking distance.
The test run is invalid if at the commencement of the test, the measured test speed of the bicycle is not less than nor greater than the test speed required by this part 1512 by 1.5 km/h (0.9 mph).
Note: No allowance shall be made for rider weight. See § 1512.5(d) for additional requirements for bicycles with both handbrakes and footbrakes.
A = [(Er / Es)(d2 / r)]
Where:
A = Ratio in meters,
Er = Illumination incident upon the receiver,
Es = Illumination incident upon a plane perpendicular to the incident ray at the specimen position (see instructions above in this paragraph (o)(2)(iii) for averaging), measured in the same units as Er,
d = The distance in meters from the receiver to the center of the wheel,
r = The minimum radius in meters of the boundary circles of the retroreflective strip.
The minimum value of A shall be that listed in table 3 of this part 1512 for each combination of entrance angle and observation angle. The plane containing the entrance angle and the plane containing the observation angle shall coincide. In table 3, a positive entrance angle corresponds to the case in which the line of sight to the receiver lies between the line of incidence and the optic axis of the reflector, and a negative entrance angle corresponds to the case in which the line of incidence lies between the line of sight of the receiver and optic axis of the reflector.
A = 4Cos2[THETA]/[1 + ([PHI]/0.225)3/2]
where A is ratio in meters, [THETA] is the entrance angle in degrees, and [PHI] is the observation angle in degrees. The criterion applies only for entrance angles from 0° to 40° and observation angles from 0.2° to 1.5°, and performance is not specified beyond this range. The values of A in table 3 are obtained from the above formula by rounding up to two significant figures. Except in cases in which the performance of the reflector is seriously questionable, a reflector with A at least the value given in table 3 at each of the six combinations of entrance and observation angles will be considered to satisfy this criteria.
16 C.F.R. §1512.18