Be warned that, per a recent Supreme Court of Appeal decision, whenever there is “reason¬able foreseeability of unlighted obstructions on the road ahead” (which probably applies to 99% of our roads!), it is up to you to take precautionary measures against a collision.  If you do hit anything, you are at great risk of being held negligent (on the basis that either you were travelling too fast in the circum¬stances, or you failed to keep a proper look-out).

Although there is (perhaps strangely) no general rule in our law that “a driver must so regulate his speed that he can stop within the limits of his field of vision”, not doing so is likely to put you in the wrong immediately because you at all times have a legal duty to “guard against dangers which [you] could or should have foreseen”.

Thus a bus driver who collided with an unlit military vehicle (broken down and partially protruding into the road) was held to have been negligent when, blinded by the lights of an approaching vehicle, he failed to “reduce his speed by braking immediately so as to be able to stop within the range of his vision or even to stop”.