A gadget for locating vehicles in town was too expensive to develop—but the solution was right at hand.
Expectations are high in the City of Copenhagen that intelligent traffic systems will be able to solve many of the problems plaguing the city: congestion, shortage of parking spaces, and peaceful co-existence between different types of road user.
A few years ago, the authorities asked the company Rambøll to come up with some ideas for how such systems could be used. Professor Per Høeg from DTU Space was involved as an expert in GPS positioning, and contributed to the 80 or so ideas the project generated.
One of the ideas was that, instead of setting up a physical payment perimeter around the city, cars could be fitted with a little gadget that could be used to pinpoint their location via GPS technology. When the time came to test some of the ideas in practice, the little gadget was quietly dropped because it was too expensive to develop. However, the idea was too good to let go, so Professor Per Høeg and his colleagues started looking at other options.
“We thought, let’s use something everyone already has in their pocket—a smartphone. These phones are constantly transmitting signals, and when they find an access point, such as your router at home, the two units start to communicate. If we made sure that all the lamp posts were fitted with WiFi, we would suddenly have the perfect opportunity to locate road users, instantly opening up a whole range of new opportunities,” explains Per Høeg, before launching into a long list:bus operations managed according to where passengers are waiting, traffic jams of cyclists untangled by providing them with a ‘green wave’ and extra space on a part of the carriageway, and apps designed to guide you to the nearest car park with vacant spaces.
The system has been tested on a short stretch of one of the busiest streets in Copenhagen: H. C. Andersens Boulevard, where six lamp posts specially designed to ‘listen for’ smartphone probe signals were installed. It works, but needs more development for a number of reasons; for example it needs to take into account that different smartphones communicate differently.