On I-15 North, right before the interchange with I-8 there is a long downhill section that promotes increased speed, along with an extra lane becoming available on the left mid way down the hill. There is an overpass at the bottom where a motorcycle cop sits and wait for motorists trying to get in the left lane and pass slower cars. You can see him from the top of the hill if you look very closely, otherwise he is obscured by the overpass pillar.