The RAC warned about limited visibility for those without automatic headlights.
Drivers are being warned they may need to turn on their headlights during the solar eclipse.
The RAC said the action might be necessary for vehicles which do not have automatic lights, to boost their visibility to other road users.
More than 90% of the sun will be obscured by the moon between 6.17pm and 8.06pm on Wednesday.
RAC head of policy Simon Williams said: “While total darkness is unlikely, those with vehicles that don’t have automatic headlights or daylight running lights may need to switch on their dipped beams to ensure they are easily visible to other road users.
“The best advice to enjoy this rare event is to pull over somewhere safe and watch with specialist glasses.”
Mr Williams urged anyone driving in a westerly direction around the time of the eclipse to avoid being distracted.
He said: “Taking your eyes off the road even for a split second to try to catch a glimpse of the sun as it disappears behind the moon increases the risk of being involved in a collision, not to mention the potential for suffering long-term damage to your vision.”
