The note explains the Police have been conducting a Road Safety Day of Action and are looking at the safety of the cars they see.
Tyres are an obvious area too look at and tread depth readings have been taken.
Any vehicle found to have a tread depth close to or under the legal limit (1.6mm) are left a ticket explaining the reason why tread is used on tyres to gain grip in the wet as well as informing the driver of which wheel they have spotted as being defective.
Rather than beng notified by the Police, we recommend you check your tyres regularily. Using a 20p coin is a good guage to see if your tyres are above the legal limit.