Extracted text: c) Explain the effect of lane width, gradient and alignment on the capacity of a highway. d) A 2-lane highway has lane widths of 2.75m, with 1.83m clear hard shoulders. There are no-passing zones along 40% of its length. The directional split is 60/40 in favour of the peak direction. The percentages of the various heavy vehicles types are: Trucks PT – 10%, Buses PB – 4%, Cars Pc – 2%. The terrain is rolling; calculate the service flow of the highway when running at full capacity.