---
title: "Camber value and disadvantages of heavy camber"
subject: "Transportation Engineering I"
chapter: 3
key: "semester_6/transportation_engineering_i:camber-selection-disadvantages"
source: https://www.bctengineer.com/q/semester_6/transportation_engineering_i/camber-selection-disadvantages
site: BCT Engineering
---

# Camber value and disadvantages of heavy camber

Transportation Engineering I · Chapter 3: Geometric Design of Highway

- Asked in: 2072 Magh, 8 marks
- Video: [WHY WE PROVIDE CAMBER IN ROAD CONSTRUCTION || TYPES OF CAMBERS BY CIVIL GURUJI](https://www.youtube.com/watch?v=GzNxYZNVJso) — Bridge Construction Training Institute
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_6/transportation_engineering_i/camber-selection-disadvantages
- Whole chapter: https://www.bctengineer.com/md/semester_6/transportation_engineering_i/chapter-3

## Question

Define camber. How is the camber value decided? What are the disadvantages of heavy camber?

## Short answer

Camber is the cross slope on straights with center higher than edges. Its value depends on surface type, rainfall, longitudinal gradient, traffic speed, and construction cost. Heavy camber causes vehicle sliding, center crowding, overturning risk, uneven wear, erosion, higher cost, and difficulty at intersections. Typical values are 1.7-4% based on surface.

## Answer

**Camber** (cross fall) is the transverse slope given to the carriageway on a straight road, with the centre (crown) higher than the edges, so that rainwater drains quickly to the side drains. It is expressed as a percentage or ratio (e.g. 2.5% or 1 in 40).

#### How the camber value is decided
1. **Type of road surface:** impervious, smooth surfaces (cement concrete, good bituminous) need less camber; rough or pervious surfaces (WBM, gravel, earth) need more.
2. **Amount of rainfall:** heavier rain needs a steeper camber.
3. **Longitudinal gradient:** a steep longitudinal gradient also drains water, so a smaller camber is enough on steep roads.
4. **Traffic speed and volume:** high-speed roads have flatter camber for stability.
5. **Cost and construction convenience:** the camber is a compromise between drainage and comfort.

| Surface | Camber (IRC) |
|---|---|
| Cement concrete, high-type bituminous | 1.7-2.0% |
| Thin bituminous | 2.0-2.5% |
| WBM, gravel | 2.5-3.0% |
| Earth | 3.0-4.0% |

(NRS 2070 gives its own values by surface type; about 2.5% is common for paved roads in Nepal.)

#### Disadvantages of heavy camber
1. **Uncomfortable and unsafe driving:** vehicles tend to slide sideways, especially in wet weather and at speed; steering is difficult.
2. **Vehicles crowd the centre** of the road to avoid the slope, causing wear at the centre and risk of head-on crashes.
3. **Overturning risk** for high vehicles when passing or overtaking on the slope.
4. **Uneven pavement wear:** the load of the wheels is concentrated at the centre and the pavement deforms.
5. **Erosion:** water runs fast, scouring the surface and shoulders.
6. **Higher cost:** more earthwork and pavement material, and the crown is hard to make at the junctions.
7. **Difficult to cross the road** or turn at intersections.

## Check yourself

The answer's key points as multiple-choice questions, with the correct option and why.

1. Which surface needs less camber?
   A. Cement concrete or good bituminous
   B. Earth
   C. Gravel
   D. WBM
   Answer: A. Impervious smooth surfaces need less camber; pervious rough surfaces need more. (Key point: Surface type)

2. How does heavy rainfall affect camber choice?
   A. It needs a flatter camber
   B. It needs a steeper camber
   C. It has no effect
   D. It needs no camber
   Answer: B. Heavier rain needs a steeper camber for quick drainage. (Key point: Rainfall)

3. Why can roads with steep longitudinal gradient have smaller camber?
   A. They are paved with concrete
   B. They have no rain
   C. The gradient also drains water
   D. Vehicles are slower
   Answer: C. A steep longitudinal gradient helps drain water, so less cross fall is enough. (Key point: Longitudinal gradient)

4. A disadvantage of heavy camber is
   A. better stability
   B. less erosion
   C. lower cost
   D. vehicles crowd the centre, causing wear and risk of head-on crashes
   Answer: D. Drivers avoid the slope and use the centre, causing central wear and head-on crash risk. (Key point: Heavy camber disadvantage)

## Related in Transportation Engineering I

- [Disadvantages of heavy camber](https://www.bctengineer.com/question.md?key=semester_6%2Ftransportation_engineering_i%3Acamber-disadvantages) — Transportation Engineering I, chapter 3