IRC: 64-1990 GUIDELINES FOR CAPACITY OF ROADS IN RURAL AREAS (First Revision) THE INDIAN ROADS CONGRESS Digitized by the Internet Archive in 2014 https://archive.org/details/govlawircy1990sp64_0 IRC 64-1990 : GUIDELINES FOR CAPACITY OF ROADS IN RURAL AREAS (First Revision) Published by THE INDIAN ROADS CONGRESS Jamnagar House. 80/(Plus Packing & Postage) . Shahjahan Road. New Delhi-110011 1990 Price Rs. New Delhi . 1990 Reprinted August. (500 copies) Ltd. Reprinted July. 2007 2011 (The Rights of Publication and Translation are reserved) Printed at Aravali Printers & Publishers Pvt.IRC 64-1990 : First Published March 1976 First Revision November. 2005 Reprinted April. ..... Recommended Design Service 11 Volumes for Two Lane Roads ... 4 5.. 10 Lane Roads Recommended Design Intermediate Lane Roads 10.. Scope . 3 3. i 2. and Concepts Service Volumes for Service Volumes for . Introduction . Equivalency Factors 8. 11. 11 Recommended Design Service Volume for Multi-Lane Roads . 9 .. 13 ... Speed-Flow Relationships .. Capacity and Design Service Volume S 7..mC : 64-1990 CONTENTS Page 1.. Recommended Design Single 9. 3 4.. Definitions . Level of Service (LOS) 6 6. . Member-Secretary 1 . especially under the Traffic Simulation Studies currently in progress. notably through the Road User Cost Study.. 1. Since then some basic research on this topic has been carried out in the country. among other things. it has been p>ossible to revise the Tentative Guidelines published earlier and place them on a 1.. These guidelines were considered by the Traffic Engineering Committee (personnel given below) in their meeting held at New Delhi on the 27th March. design and operation of roads. and for Moreover. 1990. Sikka . it is recognised that as a result of additional data coming through. more firm footing. and provides. the investments ments..K.1. the basis for determining the carriageway width to be provided at any point in a road network with respect to the volume and com1. and speed-flow relationships at a series of sites under typical in Indian traffic condition. position of traffic.4. 1. This has led to a better understanding of and volume characteristics on roads of different pavement widths and types under various conditions. At the same time.IRC 64-1990 : GUIDELINES FOR CAPACITY OF ROADS IN RURAL AREAS 1 INTRODUCTION Capacity analysis is fundamental to the planning.3.P. Bhalla . "Tentative Guidelines on Capacity of Roads in Rural Areas" were published by the Indian Roads Congress in 1976 (IRC 64-1976). R.2. the speed Based on findings from the above studies. the capacity standards may need further modification in due course. it is a valuable tool for evaluation of needed for future road construction and improveworking out priorities between the competing projects.. Convenor M. : which experiments were conducted to measure free speeds. as well as current practices in other countries. K. R V G. Ranganathan uelni raiticj.K. Sanyal (D Secretary.D. P. Rao Director.K.K.C. S.V. respectively.G.V. M Dilip Bhattacharya Dr A H.W.officio IRC - E\. Sarha ^ E^-ojjicio Gupta) E^. Srinivasan Singh P. J. Ghosh The Executive New N.Secretary of the Committee. Parulkar (V Dr.Kesvan Nair) These were processed by the Highways Specifications and Standards Committee in their meeting held on 16th April 1990.M.S. N. Arora P S.K. Raghava Chari Dinesh Mohan Dr. (S. IRC Kamdar) P. Mathur S.B.P. Palaniswamy Prof. ASRTU Delhi The Chief Engineer (NH) Kerala P.officio Corresponding Members T.C. P. Sikdar S. M. The President. S. A. Sheriff Bawa S..C.P. (RD) (K.K. Mukherjee (R. Transport Research (MOST) Mathur N. subject to certain modifications which were subsequently carried out by the Convenor and Member. The DG — The D. Merani n r c \r n Prof. Kamdar Director. Prof.IRC 64-1990 : V. Sethi Borkar G. HRS. Sarin) — Dr. 2 . These guidelines were then approved by the Executive Committee and later by the Council for publication in their meeting held on 20th March and 29th April 1990. Dr. A. Gupta Surjit S. Sharma) Deputy Commissioner [ 1 S. Vishwanath Madras Gupta Director. . Valsankar S. The guidelines are not applicable to the design of interThe capacity of these intersections will have to be determined individually. The guidelines are also not applicable to urban roads and streets. (i) Time mean speed and (ii) Space mean speed. roads.3. Speed is is the rate of motion of individual vehicles or of a metres per second. in this no control of access. at a Time Mean Speed is the Two mean speed of vehicles observed It is the mean point on the road over a period of time. Space Mean Speed is the mean speed of vehicles in a traffic stream at any instant of time over a certain length (space) of road. An understanding facilitated 3. It is measured in generally as kilometres per hour. For the purpose of these guidelines. 3.1. is outside the purview of these guidelines. In other words. sections on rural highways. the capacity of access-controlled roads.1.2.4. the norms indicated are meant to be used only when a nominal amount of animal-drawn vehicles (say upto 5 per cent) is present in the traffic stream during the peak hour. this is average speed based on the average travel time of vehicles to traverse a known segment of roadway.4. the speed measure used is "Space mean speed" traffic stream.IRC 64-1990 : SCOPE 2. 2. or more types of speed measurements are commonly used in traffic flow analysis. which is generally the case on rural highways. spot speed. For this the rural highways are considered as all-purpose 2. The capacity values recommended further on apply in general to those sections which have neither the restraints of narrow structures nor any deficiencies of visibility or other geometric features like curves. 3. 3 . with fast 2. Further. It is slightly less in value than the time mean speed. and with heterogeneous mix of and slow-moving vehicles. viz. such as expressways. DEFINITIONS AND CONCEPTS- of concept of highway capacity through a clear definition of certain terms. 2.2. Moreover.3. 3. The guidelines contained pubUcation are applicable to long stretches of rural highways as presently existing in the country. 3 . IRC 64-1990 : 3.8. The unit length is generally one kilometre. Peak-Hour Factor is defined as the traffic volume during peak hour expressed as a percentage of the AADT. per lane or per two lanes etc.9.6. Design Service Volume is defined as the maximum hourly volume at which vehicles can reasonably be expected to traverse a point or uniform section of a lane or roadway during a given time p)eriod under the prevailing roadway. is conditions. traffic and control conditions while maintaining a designated level of service. Since roads have a certain wddth and a number of a lanes are accommodated in that u^idth. It is then termed as the jamming density. ADT is the volume of Average Daily Traffic when measurements are taken for a few days.1. AADT is the Annual Average Daily Traffic when measurements are taken for 365 days of the year and averaged out.). defined as the maximum hourly volume vehicles can reasonably be expected which at uniform section of a lane or roadway during a to traverse a point or given time period under the prevailing roadway.e. The 4. Density (or concentration) is the number of vehicles occupying a unit length of road at an instant of time. 1 which are collectively known as the Fundamental Diagram of Traffic Flow. traffic and control Capacity (Vehicles per hour) 3. Density is expressed in relation to the width of the road (i. 3.e. density is SPEED-FLOW RELATIONSHIPS idealised relationship between speed. flovv^ is alvv^ays expressed in relation to the given vvddth (i. 3. Volume (or flow) is the number of vehicles that pass through a given p)oint on the road during a designated time interval.e. The peak hour volume in this case is taken as the Thirtieth Hourly Volume (i.7. the volume of traffic which is exceeded only during 30 hours in a year).) When vehicles are in a jammed condition^ the density is maximum. 3. 4. per lane or per two lanes etc. volume and expressed in the three basic diagrams given in Fig. The time unit selected is an hour or a day. 4 .5. IRC 64-1990 : 2 C ONC FN TRATION K . having value of speed equal to half the free at a speed. freedom comfort. meaning thereby that 2 5. The density-volume relationship maximum volume jamming 4. It will straight line. traffic interruptions. Six levels of service are or break-down 5. or vehicles per unit time) is considered to be the road capacity. 4 2 LEVEL OF SERVICE Level of Service is (LOS) defined as a qualitative measure des- cribing operational conditions within a traffic stream. 5.6. The following where relationship exists : Q =K. having a of density equal to half the density.V Q = Volume K = Density.5. generally described as follows : 6 Each of the levels form of can be . 1. From the idealised relationship shown in Fig. Maximum volume that can be accommodated on the road (Qmax. forced safety. and their perception by drivers/passengers. designated from A to F. having 4. 2. shows the various levels of service in the indicative volume-flow conditions. convenience and recognised commonly.e. The speed-volume relationship maximum volume is a parabola. 5. flow). at a value is a parabola.2. it can be seen that the maximum volume occurs at half the free speed and half the jamming density.3.3.e.4. free flow) and level of service F the worst (i. Level of Service definition generally describes these con- ditions in terms of factors such as speed to manoeuvre. 4. and V = Speed 4. 4.1. and travel time.IRC 64-1990 : be seen that the speed-density relationship is a maximum speed (free speed) when traffic is low and having zero speed when vehicles are jammed.2. with Level of Service A representing the best operating condition (i. Fig. because the presence of other vehicles in the traffic stream begins to affect individual behaviour. 2. but the range of flow in becomes significantly affected by interactions with others in the traffic stream.IRC 64-1990 : Q MAX. within the Level of Service B : traffic Represents a zone of stable flow. stream. Individual users are virtually unaffected by the presence of others in the traffic Freedom to select desired sf>eeds and to manoeuvre stream is high. level of comfort and convenience declines The general noticeably at this level. with the drivers still having reasonable freedom to select their desired speed and manoeuvre within the traffic stream. CAPACITY Fig. The general level of comfort and convenience provided to the road users is excellent. 7 . Level of Service C : This also is marks the beginning of which the operation of individual users a zone of stable flow. and manoeuvring within the traffic stream requires substantial vigilance on the part of the user. Level of comfort and convenience provided is somewhat less than level of service A. Level of Service A Speed volume curve shovdng : levels of service Represents a condition of free flow. The selection of speed is now affected by the presence of others. the drivers are severely restricted in their freedom to select desired speed and manoeuv re within the traffic stream. increases in flow or minor disturbances within the traffic stream will cause breakdowns Level of Service F : Represents zone of forced or breakdown flow.1. 8 . At this is level. low. Small increases in traffic flow will usually cause operational problems at this level : : when traffic volumes are The speeds are reduced to a uniform value. result CAPACITY AND DESIGN SERVICE VOLUxME From the viewpoint of smooth traffic flow. and is Represents operating conditions at or close to the capacity level. break-down occurs. Due to high volumes. This condition when the amount of traffic approaching a point exceeds the amount which can pass it. Under normal circumstances.IRC 64-1990 : Level of Service D Level of Service E Represents the limit of stable flow. Queues form behind such locations Operations within the queue are characterised by stop-and-go waves. In contrast. but relatively within the traffic way to accommodate such manoeuvres. and long occurs queues and delays 6. Vehicles may progress at a reasonable speed for several hundred metres and may then be required to stop in a cyclic fashion. for the volume" highways. it is not advis- able to design the width of road pavement for a traffic volume equal to its capacity which is available at LOS E.5 times capacity and this is taken as the "design service maximum the purpose of adopting design values. At this level. Comfort and convenience generally accomplished by forcing a vehicle to give are extremely poor. at this level. 6. Even the flow conditions at LOS C and D involve significant vehicle interaction leading to lower level of comfort and convenience. The general level of comfort and convenience is poor. Level of Service B represents a stable flow zone which affords reasonable freedom to drivers in terms of speed selection and manoeuvres within the traffic stream. with conditions approaching close to unstable flow Due lo high density. Besides. even a small increase in volume would lead to forced flow situation and breakdowns within the traffic stream. the speeds are low (typically half the free speed) and freedom to manoeuvre within the traffic stream is extremely restricted. use of LOS B considered adequate for the design of rural volume of traffic will be around 0. Freedom to manoeuvre stream is extremely difficult. Operations and driver frustration is generally high because small at this level are usually unstable. which are extremely unstable. are given in Table 1. 6.IRC 64-1990 : 6. the hourly flows need to be converted to daily values on the basis of observed or anticipated hourly pattern of traffic during the 24 hour day. traffic will experience congestion and inconvenience during some of the peak hours which may be acceptable. traffic In the context of rural highways. volumes it is usual to adopt daily for design instead of hourly volumes.1. Currently. The traffic growth rate sh. For LOS C. The unit generally employed is the passenger car unit'. design service volumes can be taken as 40 per cent higher than those for LOS B given in subsequent paragraphs. The design service volume that should be considered for design/improvement of a road facility should be the expected volume at the end of the design life. A way of accounting for the interaction of various kinds of vehicles is to express the capacity of roads in terms of a common unit. These factors are meant for open sections and should not be applied to road intersections. the peak hour factor on trunk routes in the is around 8-10 per cent of the AADT and the capacity figures recommended in the guidelines have been based on this.3.2.mid be established after careful study of past trends and potential for future growth of the traffic. Under these conditions. Therefore. It is recommended that on major arterial routes LOS B should be adopted for design purposes. The equivalenc\ factors given below are considered 7. 7. result of the 9 . On other roads under exceptional circumstances.4. The EQUIVALENCY FACTORS presence of slow moving vehicles in traffic stream is that it affects the free flow of traffic. country 6. This can be computed by projecting the present volume at an appropriate traffic growth rate. road geometries and travel speeds. LOS C could also be adopted for design. Tentative equivalency factors for conversion of different types of vehicles into equivalent passenger car units based on their relative interference value. This is a planning decision which should be taken in each case specifically after carefully weighing all the related factors. It needs to be recognised that the conversion factors are subject to variation dependent upon the composition of traffic. 50 2. The recommended design lane roads are given in Table 2.50 0.75 metre wide paved carriageway with good quality shoulders such as moorum shoulders of minimum 1. 10 service volumes of single — .00 Bullock Cart* 8.50 1.00 10. Equivalency Factor Fast Vehicles 1.SO Slow Vehicles 6. RECOMMENDED DESIGN SERVICE VOLUMES FOR SINGLE LANE ROADS 8. * 0.00 For smaller bullock-carts. Recommended pcu Factors for Various Types of Vehicles on Rural Roads 1 Vehicle Type No. Agricultural Tractor-trailer 4. Table S. Motor Cycle or Scooter 2. for purpose of these guidelines. In practice.00 Cart 3. a value of 6 will be appropriate. the same equivalency factors as given above can be used for rolling/hilly sections since the effect of terrain has been accounted for in a consolidated manner in the Design Service Volumes recommended subsequently in Tables 2. Cycle 7. 7. For safe and smooth operation of traffic. Cycle-rickshaw 8. Truck or Bus 3 00 5. 3 and 4 for different widths of road. Agricultural Tractor. Horse-drawn vehicle 4. Light 4.2. the equivalency factors u^ill vary according to However. Truck-trailer. terrain.00 Commercial Vehicle l. representative of the situations normally occurring and can therefore be adopted for general design purposes. in 8.rickshaw 3. a single lane road should have at least 3. Passenger Car. Hand 9. 8. Pick-up Van or Auto.0 metre width on either side.2. Single-lane bi-directional roads are of common occurrence low volume corridors.1.IRC 64-1990 . IRC 64-1990 : Table 2. service In locations 8.4. 8. the design volumes should be taken as 50 per cent of the values given service in quality shoulders are avail- made Table 2 9 RECOMMENDED DESIGN SERVICE VOLUMES FOR INTERMEDIATE LANE ROADS Intermediate lane roads are those which have a paveof around 5 5 with good usable shoulders on either side. 10 2 he values ecommended above are based on the assumptions that the road has a 7 m wide carriageway and good I r 11 . pavements.No. above 1900 51 • Low 1800 (O-lOOi High 1700 (above 101 Low Hilly 3. 9 1 m ment width 10 RECOMMENDED DESIGN SERVICE VOLUMES FOR TWO LANE ROADS 10 1 Recommended roads are given in Table design service volumes for two lane 4.3. I he recommended design service volumes for these roads are given in t able 3. Recommended Design Servk Terrain S. e Volumes for Single Lane Roads Curvature Degrees Suggested Design Service I Volume per Kilometrei Low Plain 1 in PCU/day 2000 (0-50) High 1 Rolling 2. where only low able (such as earthen shoulders of plastic soil). 1600 (C-2001 High 1400 (above 20 The above values are applicable for black-topped When the pavement is not black-topped. the design volume will be lower by about 20-30 per cent. 000 (above 201) 12 in PCU/day . Low Plain Design Service Volume Kilometre) in PCU/day 6. Low Hilly 5.N.500 (above 51) 2. Terrain Recommended Design Service for Intermediate Lane Roads Curvature (Decrees j>er 1. 1.000 (0-100) High 10. IN. 4.000 (0-200) High 5.200 (0-200) High 4.000 Volume (0-50) High 12. Rolling Low 5. Rolling Low 11.000 (above 101) 3 Hilly Low 7.000 (0-50) High 5.600 (above 101) 3.800 (above 51) 2.500 (above 20 1) Table S.700 (0-100) High 5.IRC 64-1990 : Table a. Terrain Plain Recommended Design Service Volumes for Two Lane Roads Curvature (Degrees per Kilometre) Design Service Low 15. 3. Capacity on dual carriageway roads can also be affected by factors like kerb shyness on the median side vehicle parking etc Tentatively. 15 per cent increase in capacity can be expected vis-a-vis the values given in Table 4.77 0. there will be a certain reduction in capacity. moorum gravel shoulder which can safely permit occasional passage of vehicles. and a minimum 3.92 0.Hi 1990 IRC earthen shoulders are available.0 m wide ccnitral verge exists. to peak The capacity of two lane roads can be increased by providing paved and surfaced shoulders of at least 1. Tablk 5 .5 metre width on either side.81 0. 11 RECOMMENDED DESIGN SERVICE VOLUME FOR MULTI-LANE ROADS 11.68 0 0.1.00 m lane lane lane 1.85 0.00 0 92 0. Table 5 gives the recommended reduction factors on this account over the capacity values given in Table 4.000 PCUs can be adopted for four-lane divided carriageways located in plain terrain. Where shoulder width 10.58 * Usable shoulder width refers to well-maintained earth.64 0. or carriageway width on a two lane road are restricted. Capac rrv Run c i ion Fa( iors Siuickstkh for Shoi'i. The capacity figures relate hour traffic in the range of 8-10 per cent and LOS B.di:r Usable* 3. Provision of hard shoulders on dual carriageways can further increase the capacity as explained in para 10 3 In case well 13 .84 1.3.75 0.8 1. Under these 10. It is assumed for this purpose that reasonable good earthen shoulders exist on the outer side. 11.2.50 shoulder width (m) > Substandard Lank and Width on Tw()-LA\^ Road m 3 25 m 3.70 0.2 0. Sufficient information about the capacity of multi-lane roads under mixed traffic conditions is not yet available. a value of 35. circumstances.6 0. Provision of hard shoulders results in slow moving traffic being able to travel on the shoulder which reduces the interference to fast traffic on the main carriageway.4. On 11.000 PCUs.3. The capacity values mentioned above relate to LOS B dual carriageways it will normally not be desirable to adopt LOS C. the dual roads can be taken up to 1.IRC 64-1990 : designed paved shoulders of capacity value of four-lane metre width art^ provided. 14 .5 40.