<story><title>Google Maps Hacks</title><url>http://www.simonweckert.com/googlemapshacks.html</url></story><parent_chain><item><author>onionisafruit</author><text>How did you fix that?  I’ve been wondering how google and the others differentiate between cars on the free vs express lanes.</text></item><item><author>nudgeee</author><text>I used to work for a mapping &amp;amp; navigation company that offered a traffic API service. It worked by using anonymized cell phone data to predict traffic patterns. I once heard a story that during peak hour, every five minutes or so the jams on a highway would magically disappear then reappear. After some head scratching, turns out there is a train track inbetween the lanes of the highway full of high speed commuters that would cancel out the stationary car commuters.</text></item></parent_chain><comment><author>labcomputer</author><text>You can measure peak acceleration--cars accelerate much faster than buses or trains--or whether you&amp;#x27;re connected to headphones (not a head-unit).  Use of headphones by drivers is illegal in most places.&lt;p&gt;As for express vs. regular lanes, express-lane cars will have much different distributions than regular-lane cars.  Use something like KNN where the distance metric is a weighted sum of Kolmogorov-Smirnov distance between speed distributions and K-S between acceleration distributions (each vehicle is one unit with a distribution of speeds and accelerations).</text></comment>
<story><title>Google Maps Hacks</title><url>http://www.simonweckert.com/googlemapshacks.html</url></story><parent_chain><item><author>onionisafruit</author><text>How did you fix that?  I’ve been wondering how google and the others differentiate between cars on the free vs express lanes.</text></item><item><author>nudgeee</author><text>I used to work for a mapping &amp;amp; navigation company that offered a traffic API service. It worked by using anonymized cell phone data to predict traffic patterns. I once heard a story that during peak hour, every five minutes or so the jams on a highway would magically disappear then reappear. After some head scratching, turns out there is a train track inbetween the lanes of the highway full of high speed commuters that would cancel out the stationary car commuters.</text></item></parent_chain><comment><author>lucb1e</author><text>I don&amp;#x27;t know what a free lane vs an express lane is, but for the &amp;quot;that&amp;quot;, I can imagine that a cluster of hundreds of phones moving at exactly the same speed in the vicinity of a train track until they reach the next station would be a reasonable indicator that the were in a train. The preexisting phones in that area would not show the property of moving at the same speed at the same time, and it also kind of stands out that they&amp;#x27;re still doing 15-30km&amp;#x2F;h (or however bad traffic may be) while the newcomer phones all rush through at 140km&amp;#x2F;h (85miles&amp;#x2F;h).&lt;p&gt;Bonus points if those clients all connect from the same IP address (range). That would be the train WiFi.</text></comment>