Background A reasonable level of visual acuity is a prerequisite not only for the safety of drivers and their passengers but also other road users. We surveyed a sample of automobile and motorbike drivers in South Wales to identify the prevalence of drivers failing to meet the visual requirements for driving as laid down by the Driver and Vehicle Licensing Agency (DVLA). Methods A random sample of 301 automobile and motorbike drivers was stopped under police supervision in a lay-by on a single carriageway in Gwent. A simple questionnaire was administered to 298 of them followed by an eyesight test wherein they were asked to read vehicle registration plates at set distances in daylight. This replicated the mandatory test administered during a person's driving test in the UK. Results There were five drivers among those tested whose eyesight failed to meet the DVLA standard for driving. This translates to 26 776 drivers in Wales and over half a million drivers in the UK. The failure rate was greater among drivers older than 40 years of age with one in 45 drivers failing the number plate test in that age group. Conclusion There is an urgent need to raise public awareness and instigate personal responsibility among drivers to maintain the required vision for driving. The magnitude of the problem raises the debate about licence renewal based on periodic mandatory vision testing and the adequacy of the current visual standards used for drivers.