Highway Development & Planning

Historical Order of Road Development

Roman Roads (from c. 312 B.C.)

Road building on a large scale was initiated by the Romans. A well-known example is the Appian Way, constructed around 312 B.C. with a length exceeding 580 km. Roman roads introduced durable multi-layer pavements and techniques that influenced later practice.

Main features:

• Roads were laid out as straight as possible regardless of local gradients.
• Total pavement thickness typically ranged from 0.75 to 1.2 m.
• The wearing course consisted of dressed large stone blocks set in lime mortar.
• Construction required removal of soft soil until a hard stratum was reached before laying the pavement.

Tresaguet Construction (Pierre Tresaguet, 1716-1796)

Pierre Tresaguet developed systematic road construction practices in France around 1764 A.D. His work introduced more scientific control of pavement thickness and drainage.

Main features:

• Overall pavement thickness of the order of 30 cm.
• Attention to subgrade moisture and surface drainage.
• Wearing surface formed with a cross slope of about 1 in 45 for surface drainage.
• Shoulder slope typically provided at about 1 in 20.

Metcalf Construction (John Metcalf, 1717-1810)

John Metcalf worked in England and followed guidance from earlier engineers such as Robert Phillip. He improved alignment selection, drainage and use of local materials adapted to site conditions.

Telford Construction (Thomas Telford, 1757-1834)

Thomas Telford worked in the early 19th century in England and recommended more engineered foundations and careful profile control.

Main features:

• Provided a level subgrade; recommended standard carriageway width of about 9 m.
• Binding layer or wearing course about 4 cm thick with cross slope 1 in 45.
• Foundation stone thickness varying from about 17 cm at edges to 22 cm at centre.

Macadam Construction (John Loudon McAdam, 1756-1836)

McAdam proposed a new, more scientific approach to road pavements in the early 19th century. His method emphasised correct layer thickness, grading of aggregates and compaction rather than very large foundation stones.

Main features:

• Rejected the need for heavy foundation stones; used broken stones of controlled size.
• Recommended small-sized aggregates for a uniform layer; lower layers compacted; typical layer thicknesses down to about 10 cm for some courses.
• Emphasised subgrade drainage and compaction; typical cross slope given as 1 in 36.
• Top-layer stone sizes chosen for stability under the predominant traffic (animal-drawn vehicles originally).
• Recommended uniform total pavement thickness with a minimum of about 25 cm.

Water Bound Macadam (WBM)

In the Water Bound Macadam method, broken stones of base and surface courses are bound together by stone dust in the presence of moisture and compaction. WBM remains a common low-cost flexible pavement type, especially for rural roads.

Modern Road Developments in India

During the British period and subsequently, a sequence of committees, acts and institutions shaped Indian road development.

Key milestones and institutions:

• In response to proposals during 1927, the Jayakar Committee was constituted in 1927.
• The committee proposed an extra tax on petrol to create a dedicated fund called the Central Road Fund.
• Most of the Jayakar Committee recommendations were accepted and implemented over the next decades:

Important actions taken:

• Central Road Fund was formed on 1 March 1929.
• A semi-official technical body, the Indian Roads Congress (IRC), was formed in 1934.
• The Motor Vehicle Act was enacted in 1939; it was later revised in 1988.
• The Central Road Research Institute (CRRI) was established in 1950 at New Delhi for applied research and technical advice on road engineering.
• The National Highway Act was enacted in 1956, empowering the central government regarding development and declaration of national highways.
• A Highway Research Board was set up in 1973 to guide road research activities nationally.
• A National Transport Policy Committee reported in 1978.

Recommendations of Jayakar Committee (summary)

• Road development should be treated as a national interest, beyond the capacity of provincial and local bodies alone.
• An extra tax on petrol should be levied to raise a Central Road Fund for road development.
• A semi-official technical body should be formed to pool technical know-how and act in an advisory capacity.
• A research organisation should be instituted to carry out R&D and provide consultations (this led to CRRI).

National Road Development Plans (20-year plans)

First 20-Year Road Plan - Nagpur Road Plan (1943-1963)

A conference of Chief Engineers convened at Nagpur in 1943 under the initiative of the IRC produced the Nagpur Road Plan, a national twenty-year road development programme. The plan classified roads into five categories and set targets for road lengths and density.

Main features:

• Road network design used a star and grid pattern for planning.
• Target total road length was 532,700 km with a road density target of 16 km per 100 km² by 1963.
• Roads were classified into five categories: National Highways (NH), State Highways (SH), Major District Roads (MDR), Other District Roads (ODR), and Village Roads (VR).
• Railway track length in areas was considered when calculating net road length: net road length = metalled road length - railway track length.

Sl. No	Category of Road	Nagpur Plan targets (km)	Achievement by 1961 (km)
-	National Highway (a) NH (b) National Trails Total NH	26,715 6,680
-	State Highway	86,825	62,052
-	Major District Roads	80,145	1,13,483
-	Total main roads (metalled roads)	2,00,365	1,98,171
-	Other District Roads	1,33,580	1,11,961
-	Village Roads	1,98,755	3,88,841
-	Unclassified Roads	-	10,49
-	Total	5,32,700	7,09,122

The total length of the primary category (metalled roads: NH + SH + MDR) was estimated by planning formulae derived for the Nagpur plan.

Variables used in Nagpur-plan formulae:

• A = Agricultural area (km²)
• B = Non-agricultural area (km²)
• N = Number of towns/villages with population in range 2,001-5,000
• T = Number of towns/villages with population over 5,000
• D = Development allowance (typically 15% of road length for forecasts in Nagpur plan)
• R = Existing length of railway track (km)

The length of ODR + VR was given by a formula:

ODR + VR (km) = [0.32 V + 0.8 Q + 1.6 P + 3.2 S] + D

Where:

• V = Number of villages with population ≤ 500
• Q = Number of villages with population 501-1,000
• P = Number of villages with population 1,001-2,000
• S = Number of villages with population 2,001-5,000
• D = Development allowance (15% in Nagpur plan)

Note: Although total road achievement by 1961 exceeded the plan targets in aggregate, the achieved lengths of NH and SH were less than the Nagpur targets.

Central Road Research Institute (CRRI)

The Central Road Research Institute (CRRI) established at New Delhi in 1950 became a national laboratory under the Council of Scientific & Industrial Research. CRRI focuses on applied research, testing and technical advice to state governments and agencies on roads and pavement engineering.

National Highway Act (1956)

Main features of the Act:

• Placed responsibility for development and maintenance of National Highways (NH) with the Central Government, provisionally.
• Empowered the Central Government to declare or omit highways from the NH list.

Second 20-Year Road Plan - Bombay Road Plan (1961-1981)

Main features:

• Targeted a road density of 32 km per 100 km² by the end of the plan period.
• Maximum distance of any place in developed/agricultural area from a metalled road: 6.4 km; from any category of road: 2.4 km.
• All towns above certain population thresholds were to be connected by metalled road: >2,000 in plains, >1,000 in semi-hill and >500 in hilly areas.
• About 16,00 km (1,600 km) of expressways were considered within the proposed NH target.
• Unlike Nagpur plan, railway length was not subtracted from road length for planning in this plan.
• A development allowance of 5% was provided (reduced from 15% in Nagpur plan).

Result: total road achievement exceeded targets overall, but construction of NH and SH still lagged behind targets.

National Highways (km)

National Highways + State Highways (km)

National Highways + State Highways + Major District Roads (km)

NH + SH + MDR + ODR (km)

Aggregate planning expressions used in the plan:

[48K + 24M + 11.2N + 9.6P + 6.4Q + 2.4R] + D

All roads (NH + SH + MDR + ODR + VR)

[48K + 24M + 11.2N + 9.6P + 12.8Q + 5.9R + 1.6S + 0.64T + 0.2V] + D

Where:

• A = Developed agricultural area (km²)
• B = Semi-developed area (km²)
• C = Undeveloped area (km²)
• K = Number of towns with population > 100,000
• M = Number of towns 50,000-100,000
• N = Number of towns 20,000-50,000
• P = Number of towns 10,000-20,000
• Q = Number of towns 5,000-10,000
• R = Number of towns 2,000-5,000
• S = Number of towns 1,000-2,000
• T = Number of towns 500-1,000
• V = Number of places below 500 population
• D = Development allowance (5% in second plan)

Third 20-Year Road Plan - Lucknow Road Plan (1981-2001)

Main features:

• Roads were classified into primary, secondary and tertiary systems.
• All villages with population over 500 (1981 census) were to be connected by all-weather roads.
• Overall road density target: 82 km per 100 km².
• The NH network was to be expanded into a square-grid concept with 100 km sides so no part of the country would be more than 50 km from an NH.
• Emphasis on environmental quality and road safety improvement.

Primary Road System (third plan)

• Included expressways of total length about 2,000 km.
• NH network based on 100 km square grids; 200 km of NH provided per 10,000 km² (i.e., 1 km per 50 km²).

Estimated NH length under this concept ≈ 66,000 km.

Secondary Road System included State Highways (SH) and Major District Roads (MDR).

Typical planning relationships used:

Length of MDR in km was estimated using county/town counts; for example:

Length of MDR (km) = 90 × Number of towns in state (planning expression used in the plan).

Tertiary Road System included Other District Roads (ODR) and Village Roads (VR).

Classification of Roads

Rural Roads

Classification may be based on:

• Traffic volume: heavy, medium or light.
• Carriage load classification: Class A, Class B, etc.
• Location and function (connectivity between urban centres, district centres, villages, etc.).

The Nagpur plan used five functional categories:

• National Highways (NH)
• State Highways (SH)
• Major District Roads (MDR)
• Other District Roads (ODR)
• Village Roads (VR)

Urban Roads

Urban road classification (not included in third 20-year plan targets) typically comprises:

• Arterial roads
• Sub-arterial roads
• Collector streets
• Local streets

Road Network Patterns

Common road layout patterns used in planning:

• Rectangular or block pattern - useful for grid-planned cities (e.g., Chandigarh).
• Radial or star and block - combines radial links with peripheral blocks.
• Radial or star and circular - adopted in places like Connaught Place (New Delhi).
• Radial or star and grid - used in Nagpur plan.
• Hexagonal pattern.
• Minimum-travel pattern - focuses on minimising average travel distance.

Planning Surveys for Road Length Requirement

To assess road length requirements and priorities, several surveys and studies are required:

• Economic studies (cost-benefit, economic viability).
• Financial studies (sources of funding, affordability).
• Traffic or road-use studies (present and projected traffic, axle loads, vehicle mix).
• Engineering studies (terrain, soils, materials, drainage, structures).

Saturation System for Calculating Optimum Road Length

The saturation system (also called the maximum utility system) estimates the optimum road length for an area by maximising the utility (service, productivity) provided per unit length of road.

Factors considered for obtaining the utility per unit length of road include:

• Population served by the road.
• Productivity served by the road network (agricultural, industrial products, market access).

Example of assigned utility units by settlement size (planning convention):

• Population < 500: utility unit = 0.25
• Population 501-1,000: utility unit = 0.50
• Population 1,001-2,000: utility unit = 1.00
• Population 2,001-5,000: utility unit = 2.00

After deciding the optimum road length for the plan period, the final step is phasing - fixing priorities for construction of specific road links based on utility, connectivity and resource availability.

Engineering Surveys for Highway Location

Before finalising a highway alignment, a sequence of engineering surveys is carried out to select and detail the most feasible route and to provide data for design and construction.

Stages of Engineering Surveys

Map Study:

Topographic maps from Survey of India (typical contour intervals 15-30 m) are used to identify terrain features, valleys, water bodies and approximate positions of bridges or major structures; they guide subsequent field surveys.

Reconnaissance:

Reconnaissance survey examines general characteristics of the area to identify feasible route corridors for detailed investigation. It is a broad visual and limited measurement study to discard obviously poor routes and shortlist candidates.

Preliminary Survey:

Preliminary survey collects the physical information necessary for alignment selection and preliminary design. Work typically includes:

• Primary traverse (control surveying and baseline establishment).
• Topographical mapping of the corridor.
• Leveling work for longitudinal profiles.
• Drainage and hydrological data collection (flood levels, channel locations).
• Soil survey (subgrade characterisation, bearing capacity).
• Materials survey (local aggregates and construction materials availability).
• Determination of candidate centre-line alignments.
• Traffic survey (existing traffic counts, growth studies, vehicle classification).

Final Location and Detailed Survey

During the location survey the final centre-line is transferred to the ground. Detailed survey work includes establishing temporary benchmarks, precise leveling for drainage and earthwork calculations, detailed cross-sections, structure locations and property/utility mapping required for design, estimates and construction.