Skip to main content

Stopping Sight Distance

Stopping Sight Distance




[caption id="attachment_1360" align="alignnone" width="540"]Stopping Sight Distance Stopping Sight Distance[/caption]






The minimum sight distance offered on a road at any spot ought to be of enough length to prevent a vehicle traveling at style speed, safety while not a collision with the other obstruction. absolutely the minimum sight distance is adequate the stopping sight distance, that is additionally some times referred to as non-passing sight distance.






The sight distance available on a road to a driver at any instance depends on :


(i) features of the road ahead.


(ii) height of the driver‘s eye above the road surface.


(iii) height of the object above the road surface.


The feature of the road ahead which affect the sight distance is the horizontal alignment and vertical profile of the road, the traffic condition and the position of obstructions. At vertical summit curves, the height of the driver‘s eye and the object above road level are more important factors affecting the visibility. The height of an object to be considered for stopping a vehicle depends on what might be a source of danger to the moving vehicle. For the aim of mensuration the stopping sight distance or visibility ahead. IRC has suggested the height of eye level of the driver as 1.2 m and the height f the object as 0.15 m above the road surface.



Hence the stopping distance available at a summit curve is that distance measured along the road surface at which an object of height 0.15 m can be seen by a driver where the eye is at a height of 1.2 m above the road surface fig



The distance within which a motor vehicle can be stopped depends upon the factors listed below:


(a) The total reaction time of the driver


(b) Speed of vehicle


(c) Efficiency of brakes


(d) Frictional resistance between the road and the types


(e) The gradient of the road.


Read More

Popular posts from this blog

Limitations of Terzaghi Theory

Limitations of Terzaghi Theory The value of the coefficient of consolidation has been assumed to be constant.  The distance d of the drainage path cannot be measured accurately in the field. The thickness of the deposit is generally variable, and an average value has to be estimated.  There is sometimes difficulty 1n locating the drainage face, sometimes thin previous seams that can act as good drainage face are missed in the boring operations. The equation is based on the assumption that the consolidation is one-dimensional. In the field, the consolidation is generally 3-dimensional. The lateral drainage may have a significant effect on the time rate of consolidation. The initial consolidation and secondary consolidation have been neglected. Sometimes these form an important part of the total consolidation. In actual practice, the pressure distribution may be far from linear or uniform. Read More Muller-Breslau principle

Price Guard Wire Method

Price Guard Wire Method Some form of  Price Guard Wire Method  is generally used to eliminate the errors caused by leakage currents over insulation. Fig. 3.14 illustrates the operation of This Method. In fig 3.14(a), a high resistance mounted on a piece of insulating material is measured by the ammeter voltmeter method. The micro-ammeter measures the sum of the current through the resistor (IR) and the current through the leakage path around the resistor. The measured value of resistance computed from the readings indicated on the voltmeter and the microammeter, will not be a true value but will be in error.   Figure 3.14 Application of  guard  circuit for measurement of high resistance In fig, 3.14 (b), the  guard  terminal has been added to the resistance terminal block. The  guard  terminal surrounds the resistance terminal entirely and is connected to the battery side of the micro-ammeter. The leakage current IL now bypasses t

Negative Booster

Negative booster A negative booster is employed to conform to the regulation that the potential difference between any two points of the rail return shall not exceed 7 V. Two boosters, positive and negative, are used which are mechanically coupled together and driven by a DC motor. The positive booster is connected to the trolley wire (near the generating station) and the negative booster (separately excited) is connected to the track rail.  The 'positive booster' adds voltage to the line while the 'negative booster lowers the potential of the point it is connected to. As we go along the trolley wire away from the generating station/sub-station, the potential drop increases, and the voltage of the trolley wire falls. Since the current returns via the track rail points away from the generating station acquire high potentials. This potential is brought down by the negative boost provided by the negative booster. When the load is sufficiently far away from the generating stati