One important job that uses mathematics is a Civil Engineer — city planning, traffic flow, schedules, etc. Here is a chart showing recommended durations for yellow lights, to allow drivers ample time to stop before the light turns red. (Source: Wall Street Journal).
Study the chart and then answer the following questions:
- a) Why are their five different colored lines? b) What do they each represent? c) Why would that factor into the stopping time of a vehicle?
- Why do you think the speed used is “Speed Limit Plus 7?”
- What other factors might need to be considered for length of yellow lights? Think of other factors that could affect stopping times of a vehicle — could stoplights be adjusted to account for those factors?