The Secret to Dash GPS's Live Traffic Data: Networked CrowdsourcingS

We're excited about the upcoming Dash Express GPS because it corrects so much of what's gone wrong with in-car navigation. In the end, you get the same green, yellow and red traffic indicators on highways that Google maps gets, plus that on some local roads. No other GPS has this. Because each unit is basically a two-way pager, it records the traffic you experience and shares it with others. It's a simple idea, perhaps, but to really harness the potentially unwieldy power of crowdsourcing, you need rules:

1. Each Dash Express anonymously and automatically sends its position and speed back to the Dash servers

2. Dash also receives traffic info from road sensors, commercial fleets and other sources through our partnership with Inrix [shown in dotted colored lines]

3. Dash then calibrates these sources against "ground truth" provided by the Dash devices actually driving the roads every day [shown in solid colored lines]

4. Dash then sends out updates to all of the Dash devices in the area with current road speeds

So what you're probably getting is that the first guy with a Dash is going to be like the goose at the head of the flock, making everything better for the rest. How many drivers in one metro area are needed until the system of realtime crowdsourced data is reliable?
For an averaged sized metropolitan area it takes just a few hundred units for the Dash Driver Network to provide live up-to-the-minute data for most major roads during commute hours.
For a major city, the number is more like 1,000, but then again, major commuter cities are probably where Dash will sell the most units up front, so I see it as a self-fulfilled prophesy kind of thing. Right now, Dash is looking only at data from its beta run, so for instance the LA map above was filled in by only about 40 testers. (Note the dotted lines where new Dash users will still rely on Inrix data.)

When the device hits the market, all those lines will go solid—green or red depending on whatever kind of hellish commuter traffic you're in for. Dash can steer you around it maybe, but it lacks the guided surface-to-surface missileage to actually make the other commuters go away. [Dash via NaviGadget]