Design Speed:
The design speed of a highway is the maximum speed at which vehicles can safely travel on the road. In this case, the design speed is given as 76 km/h.

Pavement Width:
The width of the pavement refers to the distance between the outer edges of the road surface. Here, the pavement width is given as 7 meters.

Length of Wheelbase:
The wheelbase is the distance between the centers of the front and rear wheels of a vehicle. In this case, the length of the wheelbase is given as 7 meters.

Super Elevation:
Super elevation is the banking of a road around a curve to counteract the centrifugal force acting on the vehicles. It helps in maintaining the stability of the vehicles during turning. Here, the super elevation provided is given as 1/15.

Coefficient of Lateral Friction:
The coefficient of lateral friction is a measure of the resistance to skidding or sliding of a vehicle's tires during a turn. It depends on the surface condition of the road and the type of tires. In this case, the coefficient of lateral friction is given as 0.15.

Total Width of Pavement on Horizontal Curve:
To determine the total width of pavement on a horizontal curve, we need to consider the various components involved:

1. Width of the Outer Edge:
The width of the outer edge is the distance between the outer edge of the pavement and the edge of the curve. It is calculated using the following formula:
Width of the outer edge = (V^2 * W) / (127 * R * f)
where V is the design speed in km/h, W is the width of the pavement, R is the radius of the curve in meters, and f is the coefficient of lateral friction.

2. Width of the Inner Edge:
The width of the inner edge is the distance between the inner edge of the pavement and the edge of the curve. It is calculated using the following formula:
Width of the inner edge = (V^2 * W) / (127 * R * f) - (2 * L)
where L is the length of the wheelbase.

3. Total Width of Pavement:
The total width of pavement on a horizontal curve is the sum of the widths of the outer and inner edges.
Total width of pavement = Width of the outer edge + Width of the inner edge

By substituting the given values into the equations and performing the calculations, the total width of pavement on the horizontal curve can be determined.