“The general term junction or intersection describes all roadway situations where two or more roads meet or cross one another at the same or different elevations.
The design and layout of junctions demand careful considerations from the view pint of traffic management because it is very essential to have safety of vehicular traffic and pedestrians at such places
The factors to be considered while making selection for a particular type of junction are as follows:
v Availability of means of traffic control
v Degree of traffic congestion
v Funds availablev Number of intersecting streets or roads
v Volume and nature of traffic
The basic consideration in the design and operation of intersections must be the capabilities and limitations of the drivers, pedestrians and vehicles using the facility.
The general principles to be observed in the design of junctions to minimize the risk of accidents are as follows:
- Angle of crossing
As far as possible, the acute angled junction’s should be avoided. The subsidiary roads should be made to meet at right angles to the main roads as far as possible.
At junctions, the camber usually allowed is avoided and as far as possible, the whole area of the road junction should be done in one level
The road junctions should be properly channelized i.e. the number of conflict of traffic are minimized and lines of flow of traffic are made to cross at right angles or nearly at right angles. A properly channelized road junction permits right actions to do smoothly and makes wrong actions difficult
- Entry speeds
The road junctions should be designed in such a way that high entry speeds are discouraged.
It is desirable to avoid change of gradient at the road junctions
- Importance of roads
If road junction is meant for major roads and local roads, the latter should be carried under or over the former by subways or bridges respectively
To demarcate the boundary between the road and footpath, the kerbs are provided. They should be of suitable and should be made visible at night
- Pedestrians traffic
For road junctions having heavy pedestrian traffic, the hand rails should be provided adjacent to the kerbs with opening at pedestrian crossings.
There should be ample visibility at the road junction. Each driver approaching the road junction should be capable of clearly seeing the vehicles coming from other directions. In that case only, he will be able to slow down his vehicle at junction, if found necessary.
The road junction should be made as simple as possible. The routes for traffic across the junction should be clearly defined and they should be obvious, especially if the driver is a stranger