Couple problems with them being used as "Headlights", is that they do not offer a Hi/Low beam and there is no mention of their DOT legality. Since the call them work-lights/off-road lights, they are skirting the law that way. Good looking out for alternatives though....Here is some California law regarding additional lights to avoid any issues:
A California Superior Court Clarifies The Use of Auxiliary Lights For Off Highway Enthusiasts
In California off road lights must be covered while driving on a highway, as defined in section #24411 of the California Vehicle Code. The California Vehicle Code also defines auxiliary driving lights under section #24402 as not needing covers. Each statute carefully describes the requirements for each type of light. So what’s the problem?
The confusion arose when the California Highway Patrol began defining "Off Road Light" as any auxiliary light without SAE (Society of Automotive Engineers) approval. Since this "approval" requirement is not in the law, it was never administered fairly by the California Highway Patrol. Conflicting statements from the Highway Patrol confused the public particularly if you were an off highway enthusiast. For example, have you ever heard of a Highway Officer stopping a sports car to check for SAE approval on their uncovered auxiliary lights?
Recently the El Dorado County Superior Court issued a decision that clarifies California State Law regarding the use of Auxiliary Driving Lights. A three Judge panel over-turned a lower court’s decision in which a Highway Patrol Officer had cited an off highway enthusiast for not having his two auxiliary driving lights covered. The Officer testified that if the auxiliary lights were not marked SAE Approved then they were "off road lights" and must be covered on the highway. Unable to convince the Municipal Court in South Lake Tahoe, California to interpret the law (as it was written) or obtain a logical explanation, the driver appealed to Superior Court. Representing himself, the off highway enthusiast successfully presented his case and the higher court over-turned the lower court’s decision.
In its ruling the Superior Court stated, "The uncontradicted evidence in this case demonstrates that appellant’s [the driver’s] lights fall within the definition of "driving lights" in Vehicle Code 24402. That section does not require driving lights to be covered. The administrative regulations pertaining to driving lights do not refer to any SAE requirements. While authority to regulate driving lights is vested in the CHP, there is no evidence that CHP has promulgated such a regulation and if so, what that regulation is."
In this case the driver had installed two auxiliary lights on the bumper of his 4x4 vehicle in accordance with the California Vehicle Code section pertaining to Auxiliary Driving and Passing Lights (#24402). His auxiliary lights were 38" above the ground: well within the 16-42" limit. Section #24402 also states that auxiliary driving lamps are designed for supplementing the upper beam from headlamps and may not be lighted with the lower beam. To insure compliance he wired the auxiliary lights into the dimmer switch thereby limiting their use to only high beam operation. The auxiliary driving lamps were equipped with 110 watt bulbs, which is above the legal limit for primary lamps, but these are auxiliary driving lamps--not primary lamps
Since the US Department of Transportation (DOT) does not have any regulations prohibiting a vehicle’s owner from installing auxiliary driving lights, of any power, nor do they have any regulations requiring auxiliary lights to be covered, it becomes extremely important to read and understand your own state’s laws regarding "Off Road" and "Auxiliary Driving" lights.