ABSTRACT
The basic aim of the geometric design of roads is to provide operational efficiency,
effectiveness, and safety. Considerations of traffic capacity (Section 17.4.3) will often
dominate urban and arterial designs whereas safety (Section 28.5) and flow conditions
(Section 17.4.5) will usually be the key factors in rural road design. In addition, road
design should meet driver expectancies in such a way that drivers:
* can complete their current tasks in an unhurried manner,
* are mentally ready for the form of the oncoming road, and
* are not subjected to dramatic or unexpected changes in road conditions or in
driver workload.
