# EXTRA WIDENING OF PAVEMENT

The car/vehicle has occupied extra width than it occupies at the direct part of the road. To make amends for this, the carriageway width extended the whole curved part of the road, which is known as the Extra widening of pavement on a curve.

When a car/vehicle makes a flip to barter a horizontal curve, the rear wheels do take same the identical direction as that of the front wheels. Normally the rear wheels comply with the internal direction of the curve in comparison with the front wheels.

Extra widening is the more width this is given to the curve of the pavement for the duration of its construction. In this article, we’ve defined the one-of-a-kind extra widening, requirements, and their calculation withinside under the section.
You already recognize that while you force a car, the handiest the front wheel may be turned. Then the back wheels comply with the front wheel direction instead of turning. But the primary trouble is, the back wheel does now no longer follow the right path of the front wheel. The alignment of the back wheel can be left to the front wheel if the car/vehicle flips to the left and vice versa.

This appearance is known as off-tracking and this phenomenon occurs only on short roads. The off-tracking depends upon

1. The radius of horizontal curves
2. Wheelbase length

The 2nd threat for occurring extra widening is, the driving force has an inclination to force the car/vehicle thru the outer layer of the road, a good way to get a maximum imagination and prescient of roads. So you want to provide an additional width on the outer layer of the roads.
The 0.33 danger is, whilst the car movements better than layout speeds, there can be a danger for slipping the motors to the outermost facet even as negotiating a curve.

The Extra Widening of pavement on horizontal curves is divided into two parts

1. Mechanical Widening
2. Psychological Widening

Table of Contents

### Mechanical Widening

When a car/vehicle negotiates a horizontal curve, the rear wheels comply with a route of a shorter radius than the front wheels. This phenomenon is known as off-tracking and has the impact of growing the powerful width of a street area required through the car/vehicle. Therefore, to offer identical clearance among car/vehicle traveling with inside the opposite directions on curved roads as is furnished on immediate sections, there should be a more width of carriageway available. This is an essential issue while an excessive share of car/vehicle is the use of the avenue. Trailor vehicles additionally want an additional carriageway, relying on the kind of joint. In addition speeds better than the design velocity reason transverse skidding which calls for Extra width for Some safety purposes. The expression for additional width may be derived from the easy geometry of a car/vehicle at a horizontal curve.

While negotiating a curve, rear wheels have a propensity to follow the internal track. To accommodate this, there could be a widening is supplied known as Mechanical Widening should be provided. This is because of the off-tracking of the car/vehicle.
Off-tracking in a toll road is one of the primary standards at some point of curve widening design.
The Mechanical Widening(Wm) required to account for the tracking due to the rigidity of wheelbase

### Psychological Widening

Psychological Widening (Wp) is the more width of the pavement is likewise furnished for psychological motives such as, to provide for extra maneuverability of steerage at higher speeds, to permit for the greater area requirements for the overhangs of automobiles, and to offer extra clearance for crossing and overtaking car/vehicle at the curves.

Where

Hence Total extra widening would be Ew= Wp+Wm

The widening of pavements needs to be finished for a few psychological motives also. There is a bent for the drivers to force near the rims of the pavement on curves. Some greater area is to be supplied for extra clearance for the crossing and overtaking operations on curves. IRC proposed an empirical relation for the psychological widening at horizontal curves while negotiating a horizontal curve, the motive force has a tendency to observe the internal of the pavement. This reduces the powerful width of the pavement at curves. In order to have an easy operation at curves, you want to offer an extra widening on the curve of the road.

### What do you mean by extra widening?

The car/vehicle has occupied extra width than it occupies at the direct part of the road. To make amends for this, the carriageway width extended the whole curved part of the road, which is known as the Extra widening of pavement on a curve.
The Extra Widening of pavement on horizontal curves is divided into two parts (1)Mechanical Widening (2) Psychological Widening