This stretch of I-15 is heavily trafficed weekdays with trucks and tourist RVs. The speed trap is at the bottom of a long steep grade coming out of the mountains. The patrol car hides under an overpass just as the highway curves to the right and begins to flatten out. The posted speed is 75 mph. The apparent speed of the trucks in the right (#2) lane was 85 mph, so any attempt to merge into that lane requires a higher speed.