Road junctions and intersections

A road junction is the point at which one road meets another; an intersection is the point at which two or more roads cross еach other. Both junctions and intersections are the worst danger spots in a road system.

The problems of reducing danger at these points are those of cost and space. If junctions and intersections are such that all classes of traffic meet each other at the same level, there is a danger of collision. Almost complete segregation of different classes can be achieved, and the need for users of the same class to cross traffic streams can be avoided.

All forms of road junction can be classified into three groups: multi-level junctions, roundabouts and flyover-junctions.

Multi-level junctions. The clover-leaf, the most typical of these, has already been mentioned. There is need for multi-level intersections where three conditions are fulfilled:

· only a small percentage of the traffic must turn to left or right

· the major volume of traffic is travelling on a fast through route

· the volume of traffic would otherwise be sufficient to justify the provision of a roundabout.

Roundabouts. Unlike multi-level intersections, roundabouts do not enable traffic to cross without dropping speed but pedestrians and cyclists cannot be segregated unless costly over- or under-passes are constructed.

Flyover-junctions. These have been developed chiefly at places where there are no pedestrians. These “flyovers”, which enable high speeds to be maintained, are extremely expensive, costing about ten times as much as roundabout, so it is much better to have ten roundabouts at ten dangerous junctions than a single flyover at a single junction. A combination of roundabout and flyover bridge can be of great value.

Source: Пособие по английскому языку для студентов II-III курсов строительных вузов / М.: Высш. школа, 1978. – 159 с.