Question

A radar gun used by a police officer measures your speed at a certain instant in time, whereas an officer in a plane measures the time it takes for you to travel the known distance between two stripes painted on the highway.

• What is the difference in nature between these two types of measurement and which is the fairer basis for issuing a speeding ticket?
• Would your answer change if one stripe occurred before a rest area and the other occurred after the rest area?
• Which method would be better for picking out an erratic driver who sporadically zips past cars then lags a bit?
• The radar is determining an instantaneous velocity, while the airplane method figures average velocity. Which method would be better for filtering out the dangerous drivers in thick traffic, like that described in Everyday Phenomenon Box 2.1? Which method would be easier to foil?

Transitions in Traffic Flow The Situation. Jennifer commutes into the city on ล freewลy every day for work. As she approaches the city, the same patterns in traffic flow seem to show up in the same places each day. She will be moving with the flow of traffic at a speed of approximately 60 MPH when suddenly things will come to a screeching halt. The traffic will be stop-and-go briefly and then will settle into a wavelike mode with speeds varying between 10 and 30 MPH. Unless there is an accident, this will continue for the rest of the way into the city The traffic in the upper lanes is flowing freely with adequate spacing to allow higher speeds. The higher-density traffic in the lower lanes moves much more slowly

Answer 1

Radar gun measures instantaneous velocity while a officer from plane measure average velocity over a distance between two strips Instantaneous velocity = delta x/delta t while Average velocity = Total distance/Total time taken Instant velocity is the best and fairer way for issuing speeding ticket or faltering out dangerous drivers because in thick traffic a dangerous drivers overtakes with high speed at that moment (instantaneous velocity) to zips passed cars then lags a bit or to overtake vehicles But times is not compulsory that it has high speed (average velocity) across all journey A dangerous drivers is whom who drives overtakes zips passed the vehicles with high speed at that moment (high speed at that moment is its instantaneous velocity) In case of sufficient spacing there is generally high average velocity because there is sufficient space for driving but in high traffic it is not possible to figure out dangerous driver using or by analyzing his/her average velocity so Rader gun is