This is an Australian flashing road message sign that is used in road construction or traffic diversion. The sign is trailer mounted and uses solar panels for power.
The sign has two messages, one for day and a different one for night time. The signs automatically change over at night.
Day message: Roadworks in Progress
Night message: Roadworks Please Slow Down
You can replace the messages for words or graphics of your own choice. See the readme file included.