National Rural Infrastructure Development Agency

G20 India 2023 National Flag Beti Bachao Beti Padhao

Research Areas

SOME THOUGHTS ON RURAL ROAD MAINTENANCE

Y. R. Phyll, Deputy Director
Central Road Research Institute, New Delhi

ABSTRACT

Despite phenomenal industrial progress since independence, India continues to be mainly a rural country, with only a meager 20% of its total population residing in the cities. Communication links being the precursors and harbingers economic and social development, substantial emphais has been placed on the development of road communication links in rural areas since independence particularly through Minimum Needs and other similar programmes.

Introduction

Roads are the arteries of communication and transportation, and are intended to provide a level of serviceability with regard to safety and comfort compatible with the volumes, loads and speeds of the traffic for which they are intended. The function of the road, and the type of traffic expected to use it, thus plays a very important role with regard to the functional and structural levels required for satisfactory service performance. Ensuring the minimal acceptable serviceability levels for the traffic needs at all times is the intended function of the maintenance operations.

Rural roads, as understood in the Indian national content, are the roads serving or intended to serve the rural areas and populations. They comprise the Tertiary system, and include Other District Roads (ODRs) and Village Roads (VRs). India being a predominantly rural country, with 80% of the population residing in rural areas, the importance of adequately constructed and maintained rural roads in the context of our national economy and development is self-evident. The length of rural roads in the country in 1981 was about 9.12 lakh km and is expected to more than double itself by the turn of the country. The Twenty Year Road Development Plan (1981-2001)¹ envisages the total length by 2001 to be 21.89 lakh km, or an addition of about 12.67lakh km to the rural roads.

Functions of Rural Roads and Surface Type Thereof

The main functions which rural roads are required to serve are:

  • Providing intercommunications means between villages.
  • Providing connection to market towns and/or centers of consumption or commerce or industry for rural agricultural and other produce.
  • Providing connection to centers of more advanced civic amenities like educational centers at college level, hospitals etc., and administration centers like district and Taluka headquarters.

Depending upon the size of the villages, and their economic level, which governs the type and extent of traffic generated/likely to be generated, medium or light duty roads may suffice. The type of traffic may range from bullock-carts and other animal drawn vehicles like tongas, to tractor-trolleys, and sizeable number of cases, of limited bus service and occasional trucks. There may also be sizeable cycle traffic. Depending upon the traffic mix and volume, different types of surfaces may be employed, e.g.

  • earthen or fine-grained surfaces like natural compacted/processed soil, or soil stabilised roads-low to very low volume of slow speed light traffic.
  • granular surfaces like gravel, soil-gravel or water-bound macadam-low volume of slow to medium speed light traffic with or without limited proportion of medium heavy traffic.
  • Bituminous surfaces like surface dressing or premix carpet upto medium volume of light to medium heavy traffic.

Performance of Different Type of Road Surfaces

These different road surface types perform differently under traffic, and require different type, level and extent of maintenance in each case to provide the pertinent needed level of serviceability. Thus, natural soil generally has low resistance to abrasion and deformation. Granular surfaces perform better in this regard; however, under the shearing forces exerted by medium to high speed traffic, with or without aggravation by climatic effects, loosening of the surface and dislodgement of particles takes place, with consequent development of ruts and potholes. Development of corrugations or waviness along the road at more or less regular intervals is another phenomenon exhibited by this type of roads. Gravel roads suffer from raveling and material loss. These types of roads can present the problem of dust to varying degress, particularly in dry weather.

In wet weather, problems of stability and traffic worthiness may also be encountered, needing good drainage, subgrade treatment and preferably a bituminous surfacing.

Factors influencing pavement maintenance needs are summarized schematically.

Philosophy of Road Maintenance- Some Important Imperatives

To ensure satisfactory service and serviceability levels, it is essential that the maintenance measures be:

a.adequate for the type of road surface and traffic it is required to cater to, and

b.well-planned and timely.

Effective maintenance management also calls for minimal adequate resources in terms of:

a.Finances

b.Trained personnel and appropriate equipment.

c.A need and performance evaluation system.

The Twenty Year Road Development Plan (1981-2001) points to the necessity to ‘have a review of the present policy of new construction at the cost of the maintenance of existing roads’ and emphasizes that ‘maintenance of existing assts must receive the first priority’, ‘funds for maintenance should be equal to the technical requirements as per accepted norms’ and that ‘assessment of maintenance needs be done on scientific lines’. The instructions for implementation of RLEGP³ also bring out that ‘presently the maintenance management is very poor or does not exist at all.. this cannot

be neglected any more. The assets created out of substantial investments should be maintained for meeting the traffic needs of the villages’, and indicates some of the important essentials in this regard.

Some other very important aspects, which need specially to be highlighted while formulating any system for road maintenance, are:

  • From consideration of serviceability to the user, a satisfactory road surface, with regard to riding quality, skid resistance and drainage is functionally the most important single factor.
  • Functional adequacy is, however, a surface phenomenon, only so long as the total pavement crust is structurally adequate for the intended traffic loads and volumes. A structurally inadequate pavement cannot remain functionally adequate for long, because of overstressing and deformations originating at the foundation level. Structural adequacy of the road is thus a pre-requisite for effective and economical maintenance.
  • Timely and adequate maintenance is perhaps the simplest way of economizing on maintenance. Delayed or inadequate maintenance generates faster maintenances needs, and is a drain on funds. There is an optimum time and amount of maintenance for any set of conditions and it should be attempted to achieve that optimum for effective and economic implementation.
  • Design, Construction and maintenance are closely interconnected. Adequate structural design and no stricter level of quality control during construction inhibit defects, inadequacies and thereby reduce maintenance needs. Congenital defects take their own toll in terms of additional health-care needs, and depending upon their level or seriousness, may sometimes ever call for massive therapies like reconstruction or substantial supplementary constructions.
  • Advance planning and timely execution of appropriate stage construction measures is keeping with the increase in traffic with time.

Maintenance Norms

The National Transport Policy Committee Report 4 indicates the annual maintenance requirement for rural roads in financial terms as Rs. 3000 to 14000 per km. The Twenty Year Road Development Plan 1 takes an average figure of Rs. 10,000 per km for rural roads for maintenance needs projection at 1983 price level, and recognizes the need for neutralization of escalation of prices and costs. The actual requirements for each cas

 

Serviceability Level Required Structural and Functional) Initial Serviceability Level

 

Class of Road

Adequacy of Design

 

Factors Influencing Pavement Maintenance Needs

   

Quality Control of Construction

Traffic Parameters

Volume: Adequacy of Surface Layers

Loads: Adequacy of Total Design Thickness

   

Factors Affecting Service ability Level

Climatic Conditions

Temperature:

- Temperate

- Very Hot (Desert Areas)

- Very Cold (High Altitude)

Frost Action

Snow Problems

 

Rate of Reduction in Functional and Structural Level of Service- ability

   

Rainfall:

- High

- Medium

- Low

(Arid Zone)

       

Type of Foundation and Subsoil:

- Stable

-Unstable

. Prone to slips and slides

. Prone to plastic deformation

     

Environmental Conditions

Drainage Conditions

- Depth of Water Table

-Rainfall

-General Area Contours

-Pavement Structure

. Well-draining/non-draining

-Flood Proneness

Level of Design and Maintenance Strategies Adopted

   

Factors Affecting Rate of Reduction of Serviceability Level.

 

Degree of Efficacy of the Adopted Strategy for the Given Set of Traffic, Climatic and Environmental Parameters,

Fig. 1 Factors Influencing Pavement Maintenance Needs

will depend upon the local environmental and traffic conditions, as well as degree of adequacy of thickness and type of surfacing.

The Rural Roads Manual 5 of the Indian Roads Congress provides guidance on maintenance of non-bituminous roads as follows:

  • Earth Roads Large potholes and depressions should be filled up promptly. Grading with the help of a blade grader or drag should be done periodically after which the surface should be watered and rolled.
  • Gravel and Mechanically Stabilised Roads Maintenance should be on the lines indicated for earth roads. Besides this the loss of surfacing material, which is expected to be 25mm in thickness per year should be replenished. The entire surface may be regravelled once in 2-5 years
  • Water Bound Macadam Potholes and ruts should be repaired and made up. If corrugations have affected the surfacing course, the remedy lies in resurfacing with additional thickness of at least 50mm WBM. Where the surface has raveled, resurfacing involving scarifying, addition of new materials and rolling should be done.

For rural roads with bituminous surfacing, the IRC code of Practice for Maintenance of Bituminous Surfaces of Highways indicates the provision of single cost surface dressing as per

IRC: 17-1965, and suggests following renewal periods for the surface dressing.

 
Periodicity of renewal (years)
Traffic Intensity (Commercial Vehicles per day) Low rainfall
(Upto 150 cm per year)area
Medium rainfall
(Upto 150-300 cm per year)area
High rainfall
(Above 300 cm per year)area
a. Less than 150 6 6 6
b. 150-450 6 5 5
c. More than 450 5 4 3

In addition to rural roads (ODRs and VRs), the above table covers Major District Roads (MDRs) also.

In this context, it is also of interest to note the British recommendations8 for road condition levels for maintenance operations on unpaved roads (Table 1). Tolerable levels of rutting and cracking on paved roads are shown in Table 2. For the various pavement conditions indicated in Table 2, the actions suggested are as follows:

Good, Fair - NoAction

Critical - Overlay

Failed - Reconstruction

Stipulations like the above, which clearly pinpoint the condition levels and the corresponding action which needs to taken are

TABLE 1
Recommended road condition levels for maintenance operations on unpaved roads

Defect Condition Level Action Required Type of Operation
Corrugations Less than 15 mm mean depth
15-40 mm Mean depth
Greater than 40 mm mean depth
Dragging or brushing
Grading
Heavy Grading
Recurrent
Recurrent
Periodic
Rutting Less than 15 mm mean depth
15-40 mm Mean depth
Greater than 40 mm mean depth
Dragging or brushing
Grading
Heavy Grading
Recurrent
Recurrent
Periodic
Potholes Fewer than 15 holes per 100 meters
15-40 holes per 100 meters
More than 40 holes per 100 meters
Fill
Grading
Heavy Grading
Routine
Recurrent
Periodic
Defective Camber or Crossfall Less than 1 in 25
(4 per cent)
Grading Recurrent
Loss of Material Less than 50 mm of material remaining Regravelling Periodic

Table 2

Cracking and rutting levels for paved roads

Rutting All Bases
No Cracks
Granular bases
< 1 m/m 2
Cracking stablised bases
2 m/m2
< 5 m/m 2 All bases
< 5 m/m 2
No Ruts Good Surfacing Failure Surfacing Failure Surfacing Failure Surfacing Failure
< 10 mm Good Fair Fair Critical Failed
< 20 mm Fair Fair Fair Critical Failed
< 25 mm Critical Critical Critical Critical Failed
> 25 mm Failed Failed Failed Failed Failed

very useful in providing clear-cut guidance as to what is expected of the maintenance crew, and in ensuring a minimal level of surface condition at all times.

Serviceability, Riding Quality and Surface Eveness

The serviceability of a road in terms of the level of safety and comfort as assessed by the road user (Table 3) can be closely correlated with the surface condition of the road-particularly with regard to cracking, potholes, patching, and overall riding quality9. Such correlations have been developed in India10 also for non-rural users, and show strong dependence of pavement serviceability on its riding quality, conventionally measured as an Unevenness Index by means of the fifth-wheel towed Bump Integrator at the standard speed of 30 kmph and expressed in mm per km. These correlations, though not directly applicable to rural road users, indicate the possibility of using riding quality itself as a measure of serviceability.

Table 3

Pavement Serviceability rating scale

 

Serviceability Classification Rating Range
Very Good 5-4
Good 4-3
Fair 3-2
Poor 2-1
Very Poor 1-0

The road User Cost Study in India has suggested criteria for different quality levels on terms of unevenness index values for different types of road surfaces. Those pertinent to the surface types generally used for rural roads are given:

Road Condition/Serviceability Level
Surface Type
Premix Bitumen Surfacing Surface Dressing WBM/Gravel
Good 2500-4500 4000-5000 8000-9000
Fair 4500-5500 5000-6500 9000-10000
Poor 5500-6500 6500-7500 10000-12000
Very Poor over 6500 over 7500 over 12000

At ‘Very Good’ level 2000-2500, 3000-4000 and 5000-8000 respectively could be considered as suitable values for the types of surfaces. Assuming the function of maintenance to prevent the road serviceability from falling to poor or very poor level, the threshold unevenness index values for initiation of maintenance operations for improving the riding quality is readily ascertained. Likewise, when a renewal layer is provided as a periodic maintenance measure, the criteria for new construction at very good/good level of serviceability would apply to new layer. As an overall guidelines, a terminal serviceability value of 6000mm/km has been suggested for MDRs and ODRs.

Riding quality or unevenness index is axiomatically a matter of level of surface evenness, or the magnitude and frequency of the departures from an arbitrary datum, normally or 3m straightedge. For transverse surface evenness checks, camber board is used as a datum. Guidance on the acceptable level of such departures from the specified datum is available in the IRC Manual for Rural Roads and the IRC Special Publication on Surface Evenness of Highway Pavements. The terminal serviceability criterion suggested for MDRs and ODRs terms of general maximum sizes of irregularity (for 60m unit length) under 3m straight-edge is 20mm. Average rut depth is another criterion suggested as a measure of minimum permissible serviceability level of rural roads, with maximum values of 15 mm and 40 mm being indicated for roads of category I (relatively high traffic volume and high proportion of pneumatic tyred vehicles) and category II (Relatively lower traffic volumes, with predominantly animal drawn vehicles)

The serviceability and riding quality aspect is important in road maintenance not only from the consideration of comfort and safety, but also for other important techno-economic reasons. Improved riding quality substantially reduces the road user costs12 thereby contributing towards improving the road transportation economies, as may be seen from Table-4. On the structural side, poorer riding quality means higher impact loading leading to faster deterioration with consequently higher maintenance needs and road costs. In case of animal drawn vehicles also, improved riding quality is highly desirable as it makes for lower tractive effort and reduced strain on the draught animal as well as the vehicle for any given pay load, or alternatively for increased payload capacity with the available tractive effort.

Measurement and Monitoring of Riding Quality and Surface Evenness

The riding quality of road surface is normally measured by the fifth-wheel towed Bump Integrator, an improved version of which ‘Automatic Unevenness Recorder,’ incorporating a graphical recording unit (Fig 2) has been developed by the Central Road Research Institute12. As an expeditious economical alternative, as done in case of the Road User Cost Study’

the integrator unit can be connected to the rear axle of a car, along with the necessary counter units, and used for the purpose after calibration against the towed Bump Integrator.

For measurement and monitoring the surface evenness 3m straight edge and calibrated wedge gauge is the conventional equipment. Though adequate, it is rather inconvenient and slow to use. To overcome this difficulty, the Central Road Research Institute has developed12 an ‘Unevenness Indicator’ (Fig 3), which is a traveling straight-edge device, manually operated by 2-persons, with datum wheels fixed at the ends of a 3m frame and a probing wheel in the middle. As the unit is moved at walking speed, it (a) indicates the magnitudes of bumps and depressions on a dial with magnified speed, (b) marks, with reference to any pre-set tolerance limits, the non-conforming high and low spots by throwing colour on the surface, and (c) draws attention to such spots by sounding a buzzer. The equipment is particularly useful for surface monitoring and identification of spots needing rectification, for maintenance purposes.

‘Profilograph’ (Figs. 4) is another useful manually operated device which has been developed 12 to enable recording of longitudinal surface evenness. It consists of a rectangular steel frame with a wheel base of 3 m and having a central probing wheel that follows the irregularities on the pavement under test, and records them on a paper recorder to full vertical and a conveniently reduced horizontal scale, when pulled over the surface at slow walking speed. It can be used wherever it is considered imperative to maintain a record of the road profile for future reference and study. All these devices are commercially available.

TABLE 4 Effect of change in serviceability/riding quality levels on typical road user cost components for motor vehicle transport

Cost Component Change per 1000 mm/km rise in unevenness index
Cars Jeeps Buses Trucks
1. Tyre life (km) - 2452 - 3868 - 1227 - 1238
2. Fuel consumption (liters/million km) + 342 + 592 - -
3. Engine Oil (litres/million km) + 206 + 206 + 96 + 57
4. Other oils(litres/million km) + 26 - + 82 + 26
5. Grease (liters/million km) - - + 16 + 55

Rut depth is measured by means of a wooden A-frame, with the spacing of the frame legs at the base equaling the stipulated measurement base, generally 1-4m, and a vertical graduated scale passing through the apex and middle of the horizontal member of the frame.

Need for Further Rationalisation of Maintenance Norms

This aspect can be viewed from two different angles, both of which are important in the overall maintenance context:

a.The terminal or minimal serviceability levels which should be ensured at all times.

b.The quantitative extent of maintenance needs and consequently the financial maintenance norms for different conditions.

As regards minimum serviceability levels, available indications have already been given in section 5. What is immediately needed towards further rationalisation is the evolution of unified criteria in terms of different alternative/complementary parameters for different alternative/complementary parameters for different types and surfaces of rural roads.

The assessment of quantitative extent of maintenance needs involves a knowledge of the performance needs involves a knowledge of the performance of different road surfaces under traffic. The correlations developed by the TRRL, UK studies in

Kenya, particularly with regard to the unsurfaced roads, are of interest in this connection and are given in Table 5. For rural roads in India, these correlations may not be directly applicable and would need to be validated and calibrated through appropriate studies. As a first approximation, a traffic index utilising equivalencies of 2, 1 and 0.4 for solid wheel carts, commercial vehicles and light pneumatic tyred vehicles respectively16, suggested by CRRI could be adopted to characterize the traffic parameter, to start with.

Maintenance Management of Rural Roads – Special Aspects

In addition to the imperatives already indicated in section 4 for road maintenance in general, the maintenance management of rural roads, particularly those under RLEGP and similar programmes, present some special aspects needing separate consideration. Perhaps the most important single factor is the focus on employment generation in rural areas, and the consequent stipulation of bifurcation of funds equally between labour and material components for road construction and maintenance. In the process, the quality aspect of roads inevitably suffers substantial reverses, and can even turn the intended assts into liabilities.

To prevent this trend, it is essential to identify and implement the minimal rock-bottom level of (a) quality control measures (b) simple, non-mechanised equipment,

 

Table 5
Pavement performance correlations for unsurfaced roads: Kenya Study

 

Parameter Gravel Roads Earth Roads
1. Roughness R=3250+84t
-1.62T² +0.016T³
for lateritic, quartzitic and covanic gravels

R=6500+58T
-1.0T²+0.0177³
for coral gravels

R=3250+314T
For earth roads in clay soils

R=3250+1255
For other earth roads

2. Rut Depth RD=11+0.23T
-0.0037T³
+0.000073T³
For lateritic gravels

RD=17.5+0.73T
for other gravels

RD = 14+1.2T
3. Looseness
  1. Roads graded in dry condition
  2. Gravel roads graded in wet condition

LD=1.5+14e-0.23T
LD=1.0 for lateritic and coral gravels
LD=1.5 + 5e for quartzitic and volcanic gravels

Same as for gravel roads

Notation:

R = Unevenness Inde (mm/km) fifth-wheel towed Bump Integrator.

RD = Rut Depth, mm, measured under 2m straight-edge.

LD = Loose material on surface, mm.

T = Cumulative traffic, thousands of vehicles in both directions, since grading

Note:Rd (1.22) = 0.17 + 0.87 RS (2) where RD (1.22) and RD (2) represent RD under 1.22 m and 2m straight edges respectively.

(c)mechanized equipment (e.g. road roller),(d) trained supervisory staff and (e) training of rural labour in routine road work operations. Considerable thought has gone into many of these aspects from time to time, and substantial information is already available.

The collation and digestion of this information, side by side with filling in of any gaps, and arriving at a new optimized mix with maximum feasible labour content (Table 6) compatible with quality and serviceability requirements, needs to be taken up on priority basis.

Table 6
Potential for equipment and labour

Activity

Potential for

<![if !supportEmptyParas]><![endif]> 

Equipment

Labour

Ditch cleaning and cutting

Cleaning and minor repair to culverts and bridges

Good (*)

Poor

Good (*)

Good

Building scour controls

Repair of structures

Poor

Poor

Good

Good

Grading unpaved surfaces

Good

Impracticable

Dragging and brushing of unpaved surfaces

Patching sanding or local sealing of bituminous surfaces

(Skilled)

Good

<![if !supportEmptyParas]> <![endif]>

Poor

Filling on unpaved surfaces and slopes

Grass cutting

Manufacturing signs

Poor

<![if !supportEmptyParas]> <![endif]>

Good(**)

Fair (£)

Good

<![if !supportEmptyParas]> <![endif]>

Good

Good (£)

<![if !supportEmptyParas]><![endif]> 

(Skilled) ( )

Good

Repairing and replacing traffic signs

Road line markings

Poor

<![if !supportEmptyParas]> <![endif]>

Good

Good

<![if !supportEmptyParas]> <![endif]>

Fair

Stockpiling gravel

Regravelling gravel surfaces

Stockpiling Chippings

Surface dressing

Good

Good

<![if !supportEmptyParas]> <![endif]>

Good

Good

(Skilled) (@)

Fair

Fair

<![if !supportEmptyParas]> <![endif]>

Fair

Fair

(Skilled) (@)

Notes:

(*)The potential in these activities is dependent upon suitable design of the ditch cross-section.

(**)The potential in this activity is dependent on the width of the shoulder and presence of obstructions such as road furniture and culvert headwalls.

(£)Some methods of manufacture may require the use of specialized plant (e.g. vacuum application of reflective sheeting to sign plates).

()The expression ‘Skilled’ implies that specific training of operatives is essential.

Likewise, on the executive side, in many cases a multiplicity of organisations are involved in rural road works. Judicious centralization upto appropriate levels can help in improved mobilisaiton of resources for training, quality control and equipment aspects. In this context the suggestion of establishing separate Rural Engineering Organisations at state level¹ also merits consideration, particularly from the consideration of integrated techno-economic planning and prioritisation of rural works at the state level. To start with, such organisations could be created as nuclei within the established state level engineering or rural development organisations, with appropriate linkages. While training courses-on site and at specialized organisations-will be essential for the field staff at the operational level,as indicated earlier, initial orientation courses specifically designed for the purpose would also be imperative at the senior executive level.

Acknowledgements

Thanks are due to Dr. M. P. Dhir, Director, Central Road Research Institute, for his keen interest and encouragement in the study of maintenance aspects of roads. The paper is published with his permission.

References

1.Road Development Plan for India (1981-2001), Ministry of Shipping and Transport (Road Wing, (Indian Roads Congress, 1984.

2.Some Thoughts on Maintenance Philosophy for Highway Pavements C. G. Swaminathan and Y. R. Phull, Indian Highway, Dec. 1982.

3.Instructions for Implementation of Rural Landless Employment Guarantee Programme. Department of Rural Development. Ministry of Agriculture and Rural Development. Govt. of India. 1985.

4.Report of National Transport Policy Committee. Planning commission Government of India, May-1980.

5.IRC: SP 20-1979. Manual on Route Location, Design, Construction and Maintenance of Rural Roads (Other District Roads and Village Roads) Indian Roads Congress, 1979.

6.IRC: 82-1982 code or Practice for Maintenance of Bituminous Surfaces of Highways, Indian Road Congress, 1982.

7.IRCL 17-1965 Tentative Specification for Single Coat Bituminous Surface Dressing. India Road Congress, 1965.

8.XVII World Road Congress General Report and Report of the Technical Committee on roads in Developing Areas. Permanent International Association or Road Congress, 1965.

9.Evaluation of pavement Condition by Serviceability Rating Technique. Y. R. Phull. IRC Seminar on Strengthening of Existing Road Pavements, Srinagar. Indian Roads Congress, 1971.

10.All India Serviceability Rating Study for Highway Pavements. R. K. Ghosh, Y. R. Phull et al. CRRI Special Report No. 2, Central Road Research Institute, 1977.

11.Road User Cost Study in Indian – Final Report, Central Road Research Institute, July, 1982.

12.Improving the Serviceability Levels of Our Roads. Dr. M. P. Dhir, and Y. R. Phull. Indian Highways, September, 1984.

13.IRC: SP-16-1977. Surface Evenness of Highway Pavements. Indian Roads Congress, 1977.

14.Pavement Serviceability Concept for Economical Rural Road Design, Ashok Kumar and B. D. Saha. Indian Highways, Feb. 1981.

15.Pavement Deterioration Relationships from Kenya and Brazil Studies. Y. R. Phull and P. S.R. K. Sudhakar. Pavement Performance Study Technical Paper No. 4. Central Road Research Instt. Dec. 1984.

16.Appropriate Technologies for Rural Roads Development. C.G Swaminathan and N. B. Lal. Journal Indian Roads Congress. Vol. 40-2, 1979.

17.Recommendations of Regional Workshops on Rural Road Development (Gandhinagar Feb. 1981, Nainital July 1981 Ranchi, May 1982, Hyderabad Nov. 1982). Indian Highways.

18.Men or Machines- A World Employment Program (WEP) Study on Technology and Employment,. D. Lal, International Labour office, Geneva, 1978.

Back to top