Police have been out and about today asking motorists to stop and read the registration plate of a vehicle parked 20.5 metres away - the legal standard set by the DVLA.
They are warning that drivers who fail this roadside eyesight test could have their licence revoked instantly.
Many sailed through the spot-check - but for others it was a wake-up call, as our correspondent Carl Edwards reports.
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Any showers will fade away this evening, leaving a dry night with clear skies developing across the country.
Missed Wales at Six? Catch up here.
The Welshman won stage 11 of the Tour de France in La Rosiere to take the overall lead.