The rear lighting and signaling system of automotive vehicles was considered to be one component of the traffic system which was amenable to development to provide improvements in driver performance and, hence, in accident reduction. The problem was discussed in the context of primary and augmenting cue utilization by drivers.
Various display techniques were systematically investigated employing number, functional separation, and color coding in addition to intensity and flash coding now used. A static driving simulation and actual driving tests showed that number coding, functional separation, and color were effective in reducing following driver response time, missed signals, and errors. Ratings of signal system effectiveness correlated well with objective data.
Studies concerned with color discrimination and visibility in clear and fog atmospheres showed that green-blue would be practical presence light color. Dual-intensity signals, presence lights, and forward-mounted repeater turn signals were recommended.
The most effective system for giving those signals now in use should have separate presence, turn, and stop signal lamps which should be color-coded green-blue, amber, and red.
Preliminary details of the operation, mounting constrains, candlepower, etc., of such a system are suggested.