Since at least ancient Roman times, cities have struggled over how to get pedestrians across the street safely. The current default for large intersections in most parts of the world is a traffic light that operates at fixed intervals, accompanied by buttons that sometimes do nothing at all. But as a recent UK study (pdf) found, many elderly people can’t cross in the allotted time. As a result, they are more likely than younger pedestrians to avoid busy intersections, and more likely to die or get hurt while crossing the street.

In Singapore, where the median age (pdf, page 7) has doubled from 19.5 to 38.9 since 1970, the Land Transport Authority (LTA) has tried to give elderly and disabled pedestrians the extra time they need. In 2009, the LTA started a small pilot program at five intersections called Green Man Plus. Singaporeans who are over 60 or have disabilities can apply for a special version of the LTA fare card used on trains and buses. Swiping the card at a sensor at the intersections gives them an extra 3 to 13 seconds to walk across, depending on the size of the crossing. Lights, beeps, and a vibration signal that the request been accepted. Here’s a video of the system in action:

By now, the LTA has added almost 250 Green Man Plus crossings around the city. It’s in the middle of expanding the program island-wide, with a planned total of 495 crossings by the end of 2015. The agency chooses spots where a lot of elderly people live, and where “the impact on traffic is manageable,” Sarah Lua, a spokeswoman for the LTA, tells Quartz. She adds that the agency has received “numerous requests” to extend the program to new intersections. And with the ranks of “super-aged” countries rapidly growing, it’s a model that other cities might do well to consider.