While only an estimated 16 percent of the 7 billion people on the planet carry a smartphone today, it’s looking inevitable that most, if not all, of the world’s population will have one at some point. In that case, if you know where a smartphone is, you have a good idea where the smartphone’s owner is. General Motors is counting on that by testing a wireless pedestrian detection system, in hopes of giving drivers more time to avoid potentially hitting a person.

Although both cars and smartphones are filled with sensors, the solution GM is testing doesn’t need any of them. Instead, GM is banking on wireless connectivity; specifically the Wi-Fi Direct standard. Conceptually, cars would be actively looking for Wi-Fi Direct smartphones — and the owners of those devices — and could signal an imminent collision in advance by comparing the two signals up to 656 feet apart.

The concept is similar to Ford’s own vehicle detection system that uses a different Wi-Fi standard, 802.11p, to help cars detect each other. These Wi-Fi implementations work without access points on a peer-to-peer basis, so they can be used anywhere. Pedestrians will of course need to keep their Wi-Fi radio active on their smartphones for GM’s solution to work but I don’t think that will be an issue.

Wi-Fi generally uses less battery life than mobile broadband radios, for one thing. And we’re clearly moving towards heterogeneous networks — or hetnets — with seamless Wi-Fi offload from traditional cellular networks.