Having trouble seeing the brake lights in the broad daylight, running lights/turn lights? Try this suggested settings. You can adjust the level of brightness on each light to suit. 

Go in visualsettings.dat (update.rpf/common/data) and find these lines, then replace them:

car.headlight.day.emissive.on    60
car.headlight.night.emissive.on    20
car.headlight.day.emissive.off    0.003
car.headlight.night.emissive.off    0.001
car.taillight.day.emissive.on   50
car.taillight.night.emissive.on    20
car.taillight.day.emissive.off    0.003
car.taillight.night.emissive.off    0.001
car.indicator.day.emissive.on    150
car.indicator.night.emissive.on    100
car.indicator.day.emissive.off    0.003
car.indicator.night.emissive.off    0.001
car.reversinglight.day.emissive.on    40
car.reversinglight.night.emissive.on    40
car.reversinglight.day.emissive.off 0.003
car.reversinglight.night.emissive.off    0.001
car.defaultlight.day.emissive.on    2
car.defaultlight.night.emissive.on    2
car.defaultlight.day.emissive.off    0.003
car.defaultlight.night.emissive.off    0.001
car.brakelight.day.emissive.on    100
car.brakelight.night.emissive.on   50
car.brakelight.day.emissive.off    0.003
car.brakelight.night.emissive.off    0.001
car.middlebrakelight.day.emissive.on    50
car.middlebrakelight.night.emissive.on    50
car.middlebrakelight.day.emissive.off    0.003
car.middlebrakelight.night.emissive.off    0.001
car.extralight.day.emissive.on    9
car.extralight.night.emissive.on    9
car.extralight.day.emissive.off    0.003
car.extralight.night.emissive.off    0.001
car.emissiveMultiplier 2

Original settings by Cj24