A one$-$hour traffic count has been conducted on a typical rural two$-$lane, two$-$way highway.

During this hour the speeds of the vehicles in both directions were measured and the following values were recorded:

$(2)$

Complete the table above.

Using the values as provided above, calculate the following:

a$)$ The space$-$mean speed and time$-$mean speed of the traffic flow.

$(4)$

b$)$ The space headway of the traffic flow.

$(2)$

c$)$ Utilise the calculated values from the table and determine the $50\%-$tile speed through interpolation of

the traffic flow on this road during the $1-$hour count.

d$)$ Calculate the total number of vehicles that will be using this road over the next $25$ years. The growth rate of the traffic is expected to be $1\mathrm{.}2\%$ per annum for the first $17$ years, with no growth after this period.

$(3)$

a$)\frac{12,0061}{1253}=95\mathrm{.}82k\frac{m}{h}$