Chapter 3.5, Problem 49E

To determine

(a)

To explain:

$dS/dQ<0$.

To determine

(b)

To prove:

$\frac{d^{2}S}{d{Q}^2}>0$.

Then use the fact that $dS/dQ<0\text{ and }{d}^{2}S/d{Q}^2>0$ to justify the following statement: A I-unit increase in traffic density slows down traffic more when Q is small than when Q is large.

To determine

(c)

To plot: $\frac{dS}{dQ}$. Also find the property for which this graph shows that $d^{2}S/d{Q}^2>0$.