---
title: "Classification of highway drainage"
subject: "Transportation Engineering I"
chapter: 4
key: "semester_6/transportation_engineering_i:classify-highway-drainage"
source: https://www.bctengineer.com/q/semester_6/transportation_engineering_i/classify-highway-drainage
site: BCT Engineering
---

# Classification of highway drainage

Transportation Engineering I · Chapter 4: Highway Drainage

- Asked in: 2071 Bhadra
- Video: [Types of Highway Drainage| Chapter:4|Prashant YT|CTEVT|Highway Engineering|Surface and subsurface|](https://www.youtube.com/watch?v=X1cGHkvtVdU) — Prashant YT
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_6/transportation_engineering_i/classify-highway-drainage
- Whole chapter: https://www.bctengineer.com/md/semester_6/transportation_engineering_i/chapter-4

## Question

Classify highway drainage.

## Short answer

Highway drainage is classified as surface drainage, subsurface drainage, and special drainage. Surface drainage includes longitudinal drains, camber, side drains, and cross-drainage structures. Subsurface drainage controls ground water and seepage using trench drains, blankets, and cut-off layers; special drainage covers slope and river training works.

## Answer

Highway drainage is classified as follows.

1. **Surface drainage**: removes the rainwater from the carriageway and the surroundings.
   - *Longitudinal drainage*: camber and shoulders, side drains (open or covered), catch drains, kerb and channel, gully inlets and storm sewers.
   - *Cross-drainage*: culverts (pipe, box, slab, arch), causeways, minor bridges, aqueducts and siphons, which carry water from one side of the road to the other.
2. **Sub-surface drainage**: controls the ground water, seepage and capillary water, using trench drains, interceptor drains, drainage blankets, cut-off layers and horizontal drains.
3. **Special drainage** (for slopes, hills and rivers): erosion control and energy dissipating structures, drainage of slopes and retaining walls (weep holes), and river training works.

Based on location, the drainage may also be **urban** (kerb, gully, storm sewer) or **rural** (open side drains, culverts).

## Check yourself

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

1. Highway drainage is classified mainly into:
   A. Urban and rural only
   B. Surface, sub-surface and special drainage
   C. Culvert and bridge
   D. Open and closed
   Answer: B. Surface (longitudinal and cross), sub-surface and special drainage. (Key point: Main classes)

2. Which belongs to cross-drainage?
   A. Interceptor drains
   B. Culverts, causeways, minor bridges
   C. Trench drains
   D. Camber, side drains
   Answer: B. Cross drainage carries water from one side of the road to the other. (Key point: Cross drainage)

3. Which is an urban component?
   A. Open side drains
   B. Catch drains
   C. Mitre drains
   D. Kerb, gully and storm sewer
   Answer: D. Urban drainage uses kerb, gully inlets and storm sewers; rural uses open drains and culverts. (Key point: Urban vs rural)

## Related in Transportation Engineering I

- [Requirements of highway drainage](https://www.bctengineer.com/question.md?key=semester_6%2Ftransportation_engineering_i%3Arequirements-highway-drainage) — Transportation Engineering I, chapter 4, asked 6×
- [Define highway drainage](https://www.bctengineer.com/question.md?key=semester_6%2Ftransportation_engineering_i%3Adefine-highway-drainage) — Transportation Engineering I, chapter 4, asked 5×
- [Importance of highway drainage](https://www.bctengineer.com/question.md?key=semester_6%2Ftransportation_engineering_i%3Adrainage-importance) — Transportation Engineering I, chapter 4, asked 4×
- [Components of highway drainage system](https://www.bctengineer.com/question.md?key=semester_6%2Ftransportation_engineering_i%3Adrainage-components) — Transportation Engineering I, chapter 4
- [Classification of cross drainage per NRS](https://www.bctengineer.com/question.md?key=semester_6%2Ftransportation_engineering_i%3Across-drain-classification-suitability) — Transportation Engineering I, chapter 4, asked 2×
- [Cross drainage structures and types](https://www.bctengineer.com/question.md?key=semester_6%2Ftransportation_engineering_i%3Across-drain-types) — Transportation Engineering I, chapter 4, asked 3×

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