Motion Sensors Mounted At Intersections Adjust Town's Traffic Signals -- For Bikes!

Just saw this headline on the Drudge Report.  It's the in the alarmist/scare-mongering/White-people-being-wronged tone that the site specializes in, but the actual article was pretty cool.

http://sanfrancisco.cbslocal.com/2011/08/02/motion-sensors-adjust-p...

And here's what the City of Pleasanton has to say on the matter:

http://www.ci.pleasanton.ca.us/services/traffic/intersector.html

I have many questions:

• how much do these cost?
• would this gather better metrics than whatever the city currently uses?
• Does S Vance, Ethan from ATA,  or any of the people here into the nitty gritty of urban planning with cycling in mind know if these are on the radar of Mr. Klein or anyone else who matters?
• What are the downsides?  I can possibly envision cyclists with poor senses of self-preservation/lack of common courtesy trying to abuse them at intersections where they knew they were placed, but I'm all for nobody being hit by cars, including jerks.

I've lots more questions, but that seems like a good a start.  Apologies if this is old news and just new to me (though some cursory searching showed nothing already in the forum).