An effective billboard message helps your small business build awareness. The challenge is that you need to grab attention fast as people drive by. The specific color or color combination you use in your design is not as important as using contrasting colors. You do want bolder colors rather than soft pastels, though, according to DesignMyBillboard.
With a contrasting color combination, the message colors are distinct from the background. According to Atlanta-based ActionOutdoor.com, the most impacting contrast is black print on a yellow background. Black on white, yellow on black and white on black are the next three most appealing. Blue on white and white on blue follow those closely. The best approach is to pick a color scheme that creates the impacting contrast but also matches your building, logo or advertising color schemes.