Use this fix to make car lights more visible at daytime and not too overbright at night. 
This car was adjusted and tested with this lights settings, so i recommend use them for better experience.

Change these lines in visualsettings.dat located at Grand Theft Auto V\mods\update\update.rpf\common\data

# emissive bits
car.headlight.day.emissive.on	        40.00
car.headlight.night.emissive.on	        10.00
car.headlight.day.emissive.off	        0
car.headlight.night.emissive.off	0
car.taillight.day.emissive.on	        60.0
car.taillight.night.emissive.on	        25.0
car.taillight.day.emissive.off	        0
car.taillight.night.emissive.off	0
car.indicator.day.emissive.on	        30.00
car.indicator.night.emissive.on	        10.00
car.indicator.day.emissive.off	        0
car.indicator.night.emissive.off	0
car.reversinglight.day.emissive.on	25.00
car.reversinglight.night.emissive.on	3.00
car.reversinglight.day.emissive.off	0
car.reversinglight.night.emissive.off	0
car.defaultlight.day.emissive.on	18.00
car.defaultlight.night.emissive.on	1.25
car.defaultlight.day.emissive.off	0
car.defaultlight.night.emissive.off	0
car.brakelight.day.emissive.on	        75.00
car.brakelight.night.emissive.on	30.00
car.brakelight.day.emissive.off	        0
car.brakelight.night.emissive.off	0
car.middlebrakelight.day.emissive.on	85.00
car.middlebrakelight.night.emissive.on	30.00
car.middlebrakelight.day.emissive.off	0
car.middlebrakelight.night.emissive.off	0
car.extralight.day.emissive.on	        9.00
car.extralight.night.emissive.on	9.00
car.extralight.day.emissive.off	        0
car.extralight.night.emissive.off	0
car.emissiveMultiplier	                2.00
car.sirenlight.day.emissive.on		150.00
car.sirenlight.night.emissive.on	150.00
car.sirenlight.day.emissive.off		0.05
car.sirenlight.night.emissive.off	0.04
car.emissiveMultiplier 2.00