Highway Development and Planning
Modes of Transport
- Highways—Most flexible system (house to house connection)
- Railway—Energy consumption less than highways
- Waterways—Economical but slow
- Airways—Costliest of all
- Mesopotamia 3500 BC: Invention of wheel and necessity of hard surface for wheeled vehicles to move, paved the way for road building.
- Roman roads—312 BC:
- Pioneers in road construction,
- 580 km (approximately),
- No cross-slope or gradient.
- Pierre tresaguet (1716–1796) in France:
- Father of modern highway engineering
- Thickness of road can be only 30 cm
- Cross-slope of 1 in 45 on top wearing course for surface drainage.
- Shoulders also with cross-slope to drain surface water to side drain.
Metcalf method (1717–1810) in England—similar to tresaguet:
- Followed recommendations of Robert Phillips.
- 290 km of road in northern region of England.
- His work was not recorded as he was blind.
Thomas Telford (1757–1834):
- Founder of Institution of Civil Engineers at London.
- Provided cross–slope from foundation itself by varying thickness of foundation stones.
- Provided cross-drains at intervals of about 90 m.
- No kerb stones are used.
John McAdams’ (1756–1836):
- Gave scientific method of road construction.
- Realised not to provide strong foundation at sub- grade as wheel load of traffic gets dispersed and intensity decreases at lower layers.
- Sub-grade is compacted and cross-slope of 1 in 36 is provided from sub-grade itself.
- Improvement of strength of top layers.