Dipping, and the Glare Defence

Main beam is what makes night speed possible, and the rules for giving it up are precise:

• Dip within 150 metres of an oncoming vehicle.
• Dip when following within 60 metres — your main beam in their mirrors dazzles them just as effectively as it would head-on.
• On rural curves and hilltops, dip on the approach — so you see their glow before they get your glare — and switch back to main beam once no lights are visible. That last clause matters: the rule isn't "dip and stay dipped," it's dip for people and restore your sight when nobody's there.

The handbook's reasoning is mutual: you dip so you can see oncoming headlights and won't blind oncoming drivers. It's a shared-visibility arrangement, and it only works if both sides honour it.

Which brings the practical problem: the driver who doesn't dip. Vision & Perception explained why this is more than an annoyance — dark adaptation is slow to build and instant to lose, so a main beam held in your eyes leaves you effectively night-blind for seconds after they pass, which on an unlit road is the most dangerous moment of the encounter.

The handbook's technique: look up, beyond, and slightly to the left of the oncoming lights. You keep your lane by your own left edge rather than by staring into the glare, and you protect the adaptation you'll need the instant they're gone.

Worked scenario. You're on the Naivasha–Nakuru road at 21:00 on main beam. An oncoming truck doesn't dip. Dip your own lights anyway — retaliating with main beam blinds both of you and removes the one person still able to see. Slow down, because your seeing distance has just collapsed. Look up, beyond and slightly left, holding your lane by the left edge. Be ready for what the glare is hiding — a cyclist, a pedestrian or an animal at the road edge is exactly what you cannot see right now. Once past, allow a few seconds before resuming speed; your eyes have not recovered yet, even though the road looks normal again.