I stand corrected!  I got a note about my traffic light blog this week  from Chance Baxley at my website, www.madmantraffic.com.  Chance & his co-workers work with traffic lights and told me I was wrong about pressure plates.  Nope.  No Pressure.  Electricity!  There are wires laid into those cuts you see in the pavement and they create what's called an "inductance field."  Chance tells me when a vehicle crosses over those wires, or "loops" as they're known, they detect the car's metal and the cycle kicks in.  He says some loops are looped into coordinated systems that manage the flow of vehicles.  So that's one reason why sometimes I don't think the light "sees" my car.  It's looking at the big picture.  Although he did admit smaller cars could be harder to detect because they have less metal in them.  But there's no scientific proof of that.  It still doesn't change my basic premise.  That is you still have to pull up all the way to the line.  Otherwise the system may not detect your vehicle, big or small.  And all of us behind you have to pay for it.  And my "zig-zagging" theory is still workable because I'm making sure the loops detect me being, well, loopy!  So thanks for the correction.  When it comes to telling you about traffic I don't want to take any chances.