TIM ® T RAFFIC LIGHT I NTENSITY M ETER Traffic light maintenance The CROW-publication 246 'Traffic light maintenance' offers guidance to road authority in drawing up a maintenance plan and sets legal regulations, which have to be taken in account. The plan describes three types of maintenance: inspection, preventive and corrective maintenance. Inspection During maintenance inspection the installation is investigated with the use of check- and conformity lists. The road authority has to keep the right inspection frequency to guaranty the quality of the traffic installation, but at the same time has to avoid unnecessary costs. A well maintained installation reduces the amount of failures and the risk of out of order and also increases the life span of the installation and therefore increasing safety for road users. Measuring of light intensity The intensity meter enables to monitor and register light intensity in practical situations. By regular monitoring the road authority is able to service the traffic lights in an early stage. Through early servicing traffic lights can keep meeting legal requirements. The use of an intensity meter can be an obligatory component of maintenance contracts. To secure the safety on the road, traffic lights need to be clearly visible for road users. The light intensity has to be sufficient under every (weather) circumstance, which is set in legal standards. To measure the exact light intensity of traffic lights from road level Imtech developed in association with TNO, the biggest independent research organization in the Netherlands, the traffic light intensity meter (TIM ® ). Traffic light intensity In the course of time, the luminous intensity of traffic lights slowly decreases. Possible reasons are pollution of lenses or reflectors, aging of the light source or individual LED failure. TIM® enables the road authority to carry out timely services, in such a way that traffic lights keep satisfying the statutory rules for optimal traffic safety.