reporter: well, the data set that we developed last year, in partnership with researchers from northeastern university, we have had a chance to validate that against some data and found that it is actually a very accurate representation of what appears to be out on the street. with respect to the nature of the report, which i would dispute. you know, one of the other things which i would value is that we are data-driven, and that we are transparent. that in fact, all of the data that we used to come up with this is publicly available on our website. so, they are free to download, and, if there is additional data that they think we have omitted, we would be happy to incorporate the analysis. >> all right, joe, joe castiglioni from the san francisco county transportation authority. appreciate your time, thanks for coming on. >> thanks so much. >>> let's bring in chief meteorologist bill martin for a look at the forecast. and the fog already rolling in. >> look at the fog. you see the golden gate bridge, north and south towers. that is about 720 feet to the top of this thing. the marine layer is fairly s