North Wales Police says motorists who risk lives by speeding are being targeted as part of a week-long campaign.
The crackdown is taking place as part of the European-wide initiative.
The TISPOL (European Traffic Police Network) campaign sees forces conducting random speed checks.
Matt Hemsley, from sustainable transport charity Sustrans ,says the the Assembly should make the introduction of more speed restrictions part of future policy.
"Slower speeds limits really encourage people to get out and walk and cycle, which is really good for their health" he says.
"Fast-moving traffic in communities really puts people off".
More than a hundred people have protested over the speed limit outside a primary school in Penderyn. Locals say the current 40 mph limit is too high and could lead to more accidents. They want the speed in the village reduced to 30mph, and 20mph outside the school. Jane Solomons reports.