South Australia's Royal Automobile Association says more drivers are caught speeding in summer, probably due to Christmas and holiday issues.

The RAA looked at SA police speed camera offences during the past five years and found 20 per cent more motorists were caught during summer than winter.

January is the worst month of the year with an average 8311 drivers caught, followed by December with an average 7909.

RAA senior manager road safety Charles Mountain said speeding was a significant contributor to road deaths and injuries.

"We all know speed can kill and the latest research by the Centre for Automotive Safety Research at Adelaide University shows speeding contributes to almost one in five fatal and serious injury crashes on SA roads," he said.

"Even speeding at less than 10km/h over the limit can contribute to fatal and serious casualty crashes."

Mr Mountain said there could be a couple of reasons for speeding offences spiking in summer.

"It may be that people are rushing around preparing for Christmas and also heading out on driving holidays,'' he said.

"We know many people drive to holiday destinations for their summer holidays, so we urge them to make sure they drive to the conditions, plan regular rest breaks and put their safety and that of other road users at the top of their driving agenda.''

Australian Associated Press