Are the traffic signs at the mall enforceable by the local police?

Look carefully at the signs.

They probably do not say LPD for example if you live in Lakewood.

LPD means Lakewood Police Department.

But nevertheless local police do have jurisdiction over traffic even on private property.

Think about it.

Say fireworks are illegal and you are shooting them off at your house.

The police could ticket you.

Same with this.

Cops can write tickets on those signs. The ring road you mention is private property, the property of the mall, and the mall is responsible for maintenance. This means they have to put up the signs they want, where they want. On the city streets, the city puts up those signs and writes an ordinance for each sign. For the signs on the mall property, there is a general cover-all ordinance. It normally reads something like this, "It is illegal to dis-obey any traffic control sign on private property put there for the purposes of safe and efficient traffic regulation."

Most times the cops don't sit on the mall lots waiting for violators, they have other things to do, but they do enforce the mall signs when there are complaints.

Here in the great white north (Canada). Those signs are NOT enforceable. Police only have jurisdiction for criminal offences on private property. Meaning you can get in trouble for drinking and driving or killing someone on private property but if you speed or run a stop sign that is on private property there is nothing they can do. The Ontario Traffic Act is not enforceable on private property. Sucks for you guys down there if they can.

They will give you a ticket if they see you disobeying a sign

BUT

If you call them because someone hit your car in the mall parking lot,

they will say, sorry it was on Private property !!!!

They generally cannot enforce them on their own, however in most cases the mall owner will give them permission to enforce them.