A vehicle-mounted warning light system comprises a housing containing a central light surrounded by several sets of outer lights. A controller is programmed to light the central first, and then each set of outer lights in sequence, while at the same time increasing the intensity of the lights, so that the system appears to an observer to be a single light that is getting bigger and brighter. This creates the illusion that the vehicle is travelling toward the observer faster than it actually is, thus prompting the observer to quickly yield right-of-way.