You should have watched the video in the link I provided. Last year, in Sydney alone, they said 2.2 million people participated and during that time, energy production was down 10.2% in that hour. That was equal to keeping 48,000 cars off the road as well. 10% is not a bad number. Later, QD.
But your truck's fumes make up for those 48K when you drive up and down the US......