DUBAI // Commuters who complain that the city's air-conditioned bus shelters shut down when it gets too hot have only themselves to blame, according to transport officials. Leaving the doors open is the cause of the problem, they say. The shelters are meant to provide a cool refuge from the hot and humid summer weather, but people waiting for buses have complained that it is hotter inside them than it is outside. Abdullah Yousef al Ali, the director of the buses department at the Roads and Transport Authority's Public Transport Agency, said it was aware of the complaints about the effectiveness of the shelters, but insisted they were "efficient". "From our part we confirm that these air conditioners are in fact highly efficient but the drop in their performance is attributed to the misuse on the part of some passengers who leave the door open for long periods," he said in a statement issued by the RTA. He said the hot air allowed inside the shelters then "triggers" the system to stop for a "certain period". The air quality deteriorates as a result, he added. He appealed to commuters to use the shelters properly and close the doors. Mr al Ali also said some of the shelters had not yet been connected to the electrical supply as they were still under construction. Right Angle Media, which builds and operates the shelters, previously said in a statement: "Extreme outside temperatures can cause technical difficulties at some shelters, causing the air conditioners to trip at intervals." There are now 645 air-conditioned bus shelters at 456 locations across Dubai. They will become more important once the Metro opens in September as the RTA hopes commuters will combine different forms of public transport into their journeys. An additional 41 feeder bus routes will be added before the September 9 opening date, aimed at ferrying new commuters from residential complexes. The RTA has said commuters will be no more than 500 metres from an air-conditioned bus shelter at any given time. eharnan@thenational.ae