Sir, – Lorcan Sirr refers to the problems facing people who have a disability or whose mobility is impaired and who struggle to cross in the limited time available at a pedestrian light (“Vienna leads way by designing housing with women in mind,” August 10th).In addition to its enlightened housing policy, Vienna also has smart traffic-light technology that automatically detects people with mobility impairments, crutches, rollators or strollers and extends the green crossing time. They also have buttons at wheelchair level to request a longer crossing time. – Yours etc, JACK MORRISSEY,Acorn Road,Dublin 16.