Recent advances in light-emitting diode (LED) technology have introduced many new elements into traffic signal design. This article considers how design standards can keep up with increasing requests for customisation from local authorities and traffic authorities. The basic factors to be assessed before any new traffic signal is designed include authority demands, road user demands, compatibility, and climate. Authority demands can include the diameter, order, and exact colours of the signals. Relevant US and European Standards both exist. Compatibility is crucial, because a new light housing must fit poles already in place. Electronically, the new signal system must match the old one, but it might be necessary to adjust the control equipment's monitoring system. Appropriate choice of light housing design and metals depends on the climate of the signal location. Effects of traffic signals on the environment are also important, and recycling of materials is becoming more common. Life cycle cost (LCC) analyses are already conducted in some areas, and will become more common in future, so that they will need to be improved and developed further. Tests on LEDs have shown that LED-based signals can have life spans exceeding 15 years, low energy consumption, and lower maintenance requirements.
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