Gardai warned this week that dipped headlights would be required slightly earlier due to the hour change last weekend.
Dipped headlights are now required to be used before 5pm, where previously it was 6pm.
A garda spokesperson said: "We're all more conscious of saving electricity but this does not include the proper and appropriate use of lights at night.
"Since the hour change, you now require dipped headlamps before 5pm and the evenings are becoming darker every day until the 21st of December."
Dipped lights will let you see for about 30 metres.
Here is the official guidance on when you should have your dipped headlights on;
just after the beginning (dusk) and before the end (dawn) of lighting-up hours
As long as they are needed to let you see clearly
When stopped in traffic
When meeting other traffic
In built-up areas where there is good street lighting
On continuously lit roads outside built-up areas
When following behind another vehicle
Where there is dense fog
Falling snow or heavy rain
When daylight is fading
