Car lights, settled once and for all: which, when and why 💡
Quick answer: The quick map: dipped beams — mandatory from dusk to dawn, in tunnels and in heavy rain, fog or snow; full beams — only on poorly lit roads outside towns, switching to dipped for any vehicle to avoid dazzling; front fog lights — optional in fog, heavy rain or snow; rear fog light — only in very dense fog (using it otherwise dazzles and is sanctionable); position lights — always accompany the rest; and motorcycles run dipped beams day and night. Driving unlit at night or dazzling carries a €200 fine.
Lights concentrate a disproportionate share of theory questions — and of real road errors: dazzling full beams, rear fogs on «just in case», grey cars invisible at dusk. This guide puts every light in its place, with the logic behind each rule so nothing needs blind memorising.
Each light, its moment (the exam table) 📊
| Light | When | The logic |
|---|---|---|
| Position | Whenever any other light is on; when stopped at night on an insufficiently lit road | Seeing and above all being seen: they outline the vehicle |
| Dipped (low beam) | Dusk to dawn, tunnels and underpasses, adverse weather, reversible or contraflow lanes | The «working» light: illuminates without dazzling |
| Full beam | Only outside towns on insufficiently lit roads, with no vehicle ahead or oncoming | Maximum reach — and maximum dazzle: switching down is mandatory when crossing |
| Front fog | Fog, heavy rain, snow or dust; also on signposted narrow curves | A low, wide beam that cuts the water curtain |
| Rear fog | ONLY very dense fog or precipitation | So strong that outside fog it dazzles the car behind — misuse is sanctionable |
| Reverse and indicators | Automatic in reverse; indicators in every manoeuvre | Communication, not illumination |
The 5 mistakes the exam loves (and the road punishes) ⚠️
- Full beams in town: never — urban roads count as lit, and full beams dazzle.
- Rear fog in normal rain: the classic error — dense fog or very heavy precipitation only; otherwise it punishes the driver behind.
- Not dipping when crossing: dazzle must be avoided before the other driver flashes you.
- Tunnels on daytime running lights: DRLs don't light the rear — in tunnels, switch dipped beams on manually, always.
- Dusk «I can still see»: the rule says dusk to dawn, not «when you stop seeing» — the point is that others see you.
Special cases the tests ask 🎯
Motorcycles: dipped beam mandatory in daylight too — their permanent high-vis vest. Lighting failure at night: stop somewhere safe and signal; driving unlit is among the most dangerous offences (€200). Vehicle stopped on the road at night: position lights on + signalling — this is where the V16 beacon, mandatory and connected since 2026, comes in. Overtaking at night on rural roads: you may keep full beams until drawing level with the overtaken vehicle, dipping as you pass. And the exam classic: fog in daylight? — dipped beams (plus fog lights if dense), because position lights alone are never enough in motion.
Conclusion 🏁
Lights boil down to one idea: light just enough to see without blinding anyone. Dipped as the norm, full beam as the rural exception, fog lights as surgical tools. Drill the lighting block in TraficoTest's topic tests — it's among the most profitable topics: few rules, many questions.
What searchers ask (answered head-on) 🔍
The exact phrasings people type into Google and AI assistants — answered head-on:
«when must car lights be on in Spain?»
Dipped beams from dusk to dawn, in tunnels and in heavy rain, fog or snow; full beams only on unlit rural roads with nobody to dazzle; rear fog only in very dense fog. Motorcycles run dipped beams in daylight too.
«which lights in fog?»
Day or night: dipped always, front fogs if dense, and the rear fog only when very intense — otherwise it dazzles the driver behind and is sanctionable.
«what's the fine for driving without lights?»
Unlit night driving or dazzling with full beams are serious offences at €200; and in tunnels DRLs aren't enough — they leave the rear unlit.
Frequently asked questions ❓
When are dipped beams mandatory?
From dusk to dawn, in tunnels and underpasses, in adverse weather and on reversible or contraflow lanes; motorcycles run them in daylight too.
When can full beams be used?
Only outside towns on insufficiently lit roads without risk of dazzling: you must dip for any oncoming vehicle or one you approach from behind.
When is the rear fog light used?
Only in very dense fog or precipitation: in any other conditions it seriously dazzles the driver behind and misuse is sanctionable.
What's the fine for driving unlit at night?
It's a serious offence carrying a €200 fine, the same as dazzling through improper full-beam use.
Do daytime running lights work in tunnels?
No: DRLs leave the rear unlit, so in tunnels you must switch dipped beams on manually even if the car looks lit from the front.