A Scottish council is resorting to psychological tactics to win the war against speeding drivers.
The sign gives a reaction to speed
Electronic roadside signs in Perth and Kinross smile at drivers who approach them within the speed limit, and grimace at those who fail to slow down.
Transport department spokesman Chic Haggart said the radar controlled signs have been sited outside schools and are as much a classroom aid for teachers as a reminder to motorists.
"We're trying to get the kids to buy into the concept of driving at a sensible speed," he said.
The scheme has also generated interest from Tayside Police and will be operated by traffic wardens.
The face is designed to be moved around, and can be set up quickly in areas where local residents have complained about speeding motorists.
As with traffic 'guns', the speed of the oncoming car is detected by radar.
"The effect is quite marked with those travelling at excessive speeds and it has been very positively received so far," Chic claimed.
This is not about punishing people, we want to change the culture
Chic Haggart, Perth and Kinross Council
Motoring organisations like the Automobile Association (AA) have given the smiley face a welcome.
"People are rightly penalised for speeding," said the AA's head of policy in Scotland, Neil Greig.
"But careful and responsible drivers don't usually get praised for their good behaviour.
"We have no objection to this, if it makes people feel better."
Police in the Highlands are already using the signs and Ayrshire is experimenting with them too, according to the company behind the smile, Counters and Accessories.
"We've had lots of interest since we started importing them from Germany a little over a year ago," said company spokesman Tony DiMonaco.
Tony said some councils were sceptical at first: "I remember giving a demonstration to a road safety officer in Barking.
"At the start he said 'I don't like this it trivialises speeding'.
"But within half-an-hour of seeing it in operation, he was all for it."
The face is designed to be moved
Chic Haggart considers that although the smiling face may be eye-catching, it is anything but a gimmick.
However, he does admit the effect of the sign may wear off with driver familiarity.
That is one reason, he said, why the signs are constantly moved around.
"We are most concerned about where we have vulnerable pedestrians, like outside school - but this is not about punishing people, we want to change the culture."