Answer to this week's riddle

Travis Hale

Again, the riddle:  

The colloquial name for this type of vehicle comes from the original name of the device used to calculate a client's use.

Answer:  "The name taxicab  - usually abbreviated to taxi - derives from the taximeter, the instrument which measures the distance travelled - or time taken - thus allowing an accurate fare to be determined. This device was invented by the German inventor, Wilhelm Bruhn in 1891."

Source:  http://inventors.about.com/od/inventionhistory/a/Archive_seven_2.htm