The U.S. limit on high beam axial intensity was 37,500 candlepower per side of the vehicle until 1979, when it was raised to 75,000 candlepower per side of the vehicle*—*that is the current limit, though everywhere else in the world the limit is above 140,000 candlepower per side of the vehicle. Note this is a restriction on axial intensity, not a restriction on intensity anywhere in the beam.
This is why the sealed beam is not well regarded. Also the sealed beam bulbs were initially incandescent. This means that the light had a golden hue to it. This makes distinguishing between what is lit and what is not lit more difficult. The H2 / H4 bulbs tend to produce whiter light and makes the distinction more obvious. Note that the first US production car without sealed beams, the Ford Taurus, came out in 1986. Also, all measurements made at 12.8 v DC.
At the same time in Europe car headlights on high where limited to 110.000 candlepower each. The limit in Europe has varied from 102,500 to 215,000 per side of the vehicle over the last sixty years or so.
FWIW Dept.: Not all candlepower is good power. I have a single 55 watt yellow lens fog lamp, and a pair of 110 watt clear lens driving lamps. The latter are rated at 333,000 candlepower each.
On a clear night on a straight flat road, along with the high beams the driving lamps will illuminate non-reflective objects at up to 0.6 miles away, reflective objects will show up at a mile or more. If turned on to illuminate through fog, however, they render a visually impenetrable white sheet directly in front of the car. When turned on, everything else in the car gets dimmer.
The single yellow fog light, in conjunction with the low beams, in approximately the same amount of fog, yield slightly less distance than low beams only on a clear night. A clear fog lamp might give similar results, but IMHO, the yellow has less glare.
