Reports say the optical illusion works in such a way that it cannot be seen until the last minute. Also, it's been placed to give drivers enough notice to smoothly apply the brakes, unless the driver is speeding. If the driver is exceeding the limit the picture is designed to 'flash' up very fast, scaring the motorist into slowing down.
It's a great initiative that would be both effective at reducing speed and one that could be applied on a relatively cost-friendly budget. The West Vancouver authorities are hoping to extend the method further throughout the region.