Sunday, 26 August 2018

Components of a City Road-Footpath,Kerb,Pedestrian Crossing,Traffic lane,Median


Following components of a city road described below

Footpath  

The portion of roadway of an urban road reserved only for pedestrians is called footpath.They are provided in urban areas when the vehicular as well as pedestrian traffic are heavy ,to provide protection to pedestrians and decrease accident.Footpaths are generally provided on either side of the road and the minimum width should be 1.5 m.

kerb

A kerb (also termed as curb)is a vertical or sloping member provided along the edge of a pavement or Shoulder to give strength and protect the edge of pavement.It Indicates the boundary between the pavement and shoulder or sometimes island or footpath or car parking space.

kerb are generally constructed of cut stone or cement concrete slabs.The kerbs are usually divided into three groups based on their function.
i) Low or mountable kerb.
ii) Semi barrier type kerb. 
iii) Barrier type kerb.

The kerb and the road surface near the edge together from a side channel which carries rain water that comes from the road surface.

Pedestrian Crossing or Cross Walk Line 

The particular places of a road where pedestrians cross the pavements are properly marked by pavement marking .This portion of pavement is called pedestrian crossing or cross walk line.The width of pedestrian crossing may be between 2.0 m and 4.0 m depending on the local requirements.

Pedestrian crossings should be provided at important road intersections or some other places to enable the  pedestrians to cross safely the road of heavy traffic.The location of pedestrian crossing should be so selected that the pedestrians are subjected to minimum difficulty.

Traffic Lane

The carriageway constructed for single line of traffic movement is called a traffic lane.The lane width is determined on the basis of the width of vehicle and the minimum side clearance for safety. 

When the side clearance is increased up to a certain limit there is an increase in operating speed of vehicles and hence an increase in capacity of the traffic lane.The width of carriageway depends on the width of traffic lane and number of lanes.

Median or Central Reserve or Traffic Separator

A median or central reserve is the longitudinal space separating the dual carriageway it is also known as traffic separator. 

As per I.R.C recommendation,the minimum desirable width of median is 5 m for rural highway which may be reduced up to 3 m where the land is restricted.The absolute minimum width of median in urban area is 1.2 m and desirable minimum width is 5 m.

Advantages of Median or Central Reserve or Traffic Separator

⇰ It prevents head on collision between vehicles moving in opposite directions on adjacent lane.

⇰ It helps in channelizing the traffic stream at intersections.

⇰ It helps in segregating slow traffic and protects pedestrian.

⇰ It provides a stopping area in case of emergencies.

⇰ It provides space for future widening of  carriageway.

Disadvantages of Median or Central Reserve or Traffic Separator

Provision of median increase the width of right of way. So where the land is costly, the total cost may be very high.