I was sick from work today and I thought maybe it was Work calling to check up, but I see now it's a prank or scammer called me at 8am and rang just once

The number 2014378480 rang once at 5:59am est and again at 7:11am est. Just rings, nothing on the line. I am reporting and blocking the #

Got a call from (201)437-8480 on April 4, 2016, 6:55pm pdt.
The caller identified herself as Martha and said they were doing a survey of transportation and mobility for San Diego. She hung up just as she was about to start asking her questions.

Called and said hat he was conducting a survey of transportation in Columbus, Ohio.  I asked if I could ask some questions first and he said "Yes".  I asked where he was and he said "Washington, DC".  I told him he was a liar because his number (49-201-437-8480) was not Washington, DC. - and that he was a fraud.  He then said he was calling from his computer.  I told him that masking his number with a fake one was a violation of federal law.  He told me I could google his company and I told him i would google him to federal charges and hung up.

Call came in from this number preceded by country code +49.  When I answered, only silence then call ended.  Does anyone have a theory what the caller is trying to accomplish with all these non calls?