The council bought a "speed alert device'' that reads the speed of oncoming cars, which is displayed on an electronic sign.

The device will be put in place in school zones to remind drivers to slow to 40kmh when the reduced speed limit is in force from 8-9.30am and 2.30-4pm on school days.

Sutherland Shire Mayor Lorraine Kelly said the sign was an educational tool and would not be used as a basis for fines.

"Police can't be everywhere so Sutherland Shire Council staff will be setting up this speed alert display when they visit schools to monitor school parking restrictions,'' she said.

"Every school community has stories about close calls students have with traffic.

"Slowing down around schools gives drivers more time and opportunity to avoid small children if children cross unsafely.

"A child hit by a car going faster than 40kmh has a much greater chance of being seriously injured or killed than a child struck by a slower moving car.

"In fact, a child hit by a car at 50kmh is equivalent to the impact caused by dropping that child off a three-storey building.''

The council also announced a number of changes to help improve safety and access to parking spaces.

These include extending bus and no parking zones outside schools at Gymea and Burraneer, traffic calming and more pedestrian-friendly conditions at Cronulla and adding more short-term parking at Kirrawee to increase availability in the busy commercial area.

"Council engineers are continually working with the community through our Sutherland Traffic Committee and Consultative Traffic Forum to adjust parking and traffic conditions to ensure public safety and optimise road use and parking availability,'' Cr Kelly said.

"Sutherland is one of the few remaining areas in Sydney where there is no cost for parking and, for this to continue, motorists need to be considerate of one another.''

Do you think the speed alert devices are a good idea?