Yes, you can legally drive your car without daytime running lights (DRLs) in most situations in the United States, as they are not federally mandated. However, your vehicle's standard headlights, taillights, and other required lighting must be functional and used appropriately. The critical factor is visibility: if you need to increase your vehicle's visibility to other drivers—during dawn, dusk, rain, fog, or overcast conditions—you are legally required to turn on your regular headlights.
Daytime running lights are a separate, low-intensity front light system designed to make your car more visible during daylight hours. While studies from organizations like the National Highway Traffic Safety Administration (NHTSA) have shown DRLs can reduce certain types of daytime multi-vehicle crashes, they are not a substitute for your primary lighting system. Many modern cars have automatic lighting settings that handle this decision for you. If your car lacks this feature, a good rule of thumb is, "Wipers on, lights on"—if your windshield wipers are needed, your headlights should be on too. Relying on DRLs alone at night or in low-light conditions is dangerous and illegal, as DRLs do not illuminate the road ahead or activate your taillights, making you virtually invisible to drivers behind you.
Ultimately, the legality depends on state law and ambient conditions. The safest practice is to manually turn on your full headlights whenever visibility is less than perfect to ensure you can see and, just as importantly, be seen.
