An effective, low-cost, short-term measure to enhance safety and efficiency is to aid driver information handling by improving the highway information system. Reducing driver error, a factor in most highway system failures, reduces accidents and improves operations. The literature shows improved driver performance and lower accident involvement with enhanced traffic control devices. A human factors analysis identifies sources of driver error and measures for their reduction. Errors are found to stem from information processing demands and information display suitability. Information system deficiencies include missing, erroneous, nonuniform, nonstandard or obscured traffic control devices. Optimized displays providing positive guidance is shown to aid driver performance. It is concluded that the information system should be improved to insure standardization, uniformity, and suitability.