Electronic School Zone Signs
24 May 2007
In January 2007, AD Engineering completed a project in Perth, Western Australia, on behalf of the Main Roads Western Australia (local transport authority) and Downer Engineering Pty. Ltd. This project required the design, construction, installation and maintenance of Electronic School Zone Signs (ESZS) at various school locations throughout the Perth metropolitan area in Western Australian.
The Electronic School Zone Signs (ESZS) were developed to provide a visual alert system to inform road users of the maximum allowable speed limit for a specified operating period in a high-risk area e.g. the critical period of children's arrival and departure from a school zone.
The signs comprise of white Light Emitting Diode (LED) digits depicting the speed limit in the sign centre, surrounded by two annuli of flashing and static red LEDs.
The electronics are enclosed in an aluminum weatherproof (IP56) enclosure that is water, vandal and dust resistant and they are powered by an enclosed battery and fitted solar panel. The ESZSs are fitted with a polycarbonate, non-reflecting UV stabilized screen for high visibility in direct sunlight.
A full duplex 912Mhz GFSK transceiver link communicates with the adjacent ESZS for flash synchronization and software commands. The signs can also communicate via SMS on alarm (including a tilt sensor) to a nominated telephone number to ensure the relevant authorities are contacted immediately in the event of a breakdown.
The signs are fitted with a GSM modem for remote software configuration including programmable operation times.
The ESZS can be fitted with a radar device to activate the red LED annulus to flash when a vehicle is detected exceeding the speed threshold setting.
The highly visual ESZS have received considerable public comment on their effectiveness to warn and slow speeding motorists of their approach to a high risk school zone.
