In many cars, the daytime running lights are also the headlights. Mine are in a 2013 Subaru Outback. However, they remain separate from my turn signals and do not deactivate when my signal activates.

For more modern vehicles, they have to turn off the LED/Laser-phosphor unit entirely because the lights design is too radiant and glaring for the turn signal to be seen. GMC and Ford big-ass trucks made within the last 5 years are an example.