A little Googling yielded this...
Here is the Bright sun scenario...
The false laser alerts are caused by bright, repetitive reflections off the white painted road stripes at the center of the highway. It is also caused by bright reflections off the metal side rails along side the highway. This false noise does not occur very often and is caused by bright light reflections at a particular frequency.
..and the type of vehicle scenario...
Laser Falsing
It is unusual to get false laser warnings. Some cars and other electronics put out more RF interference than others and that interference may cause a false laser alert when certain devices are used. Although rare, using the horn, windshield wipers, or accelerating, can generate RF interference in some vehicles. Does it do the same thing in other cars/trucks? New cell phones, new cars with laser adaptive cruise control, and the wind-shear equipment at some major airports can also cause false laser alerts.
That Laser adaptive cruise control may be the problem...
Damn Nannies...