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Traffic Census on Non-Urban Roads

IRC 9 (1972) provides standardized guidelines for conducting traffic censuses on non-urban roads in India, focusing on trunk routes such as National Highways, State Highways, and Major District Roads. It details the selection of census points, frequency and duration of counts, data recording methods, and compilation procedures to ensure uniform and reliable traffic data collection for highway planning and management.

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What This Standard Covers

IRC 9 (1972) provides standardized guidelines for conducting traffic censuses on non-urban roads in India, focusing on trunk routes such as National Highways, State Highways, and Major District Roads. It details the selection of census points, frequency and duration of counts, data recording methods, and compilation procedures to ensure uniform and reliable traffic data collection for highway planning and management.

Who Uses This Standard

  • Highway Planning Engineers
  • Traffic Surveyors
  • Transportation Planners
  • Road Maintenance Authorities
  • Government Highway Departments
  • Traffic Data Analysts
  • Civil Engineering Consultants

Key Topics Covered

Selection of traffic census points
Frequency and timing of traffic counts
Duration and scheduling of census operations
Classification of vehicle types for counting
Manual data recording techniques
Shift organization and enumerator roles
Data compilation and summary forms
Handling abnormal traffic conditions
Preservation of traffic data records
Use of index maps for census locations
Reporting and data dissemination protocols
Standardization across highway departments

Table of Contents

1Introduction

The IRC 9 Introduction outlines the methodology for traffic census including selection of census points, frequency, data recording, and compilation. Key points include:

  • Census points should remain consistent for subsequent counts; new points may be added as needed (Clause 3.4).
  • Traffic counts must be conducted at least twice yearly, covering peak and lean seasons, for 7 consecutive days and 24 hours each day (Clause 4.1).
  • Data recording divides the day into three 8-hour shifts with enumerators recording traffic by vehicle type and direction using tally marks (Clause 5.1 to 5.4).
  • Compilation involves daily and weekly summary sheets, highlighting peak hour traffic, and maintaining records for at least five years (Clause 6.1 to 6.4).

Tables provided include detailed formats for field data sheets, daily traffic summaries, and weekly traffic summaries, capturing vehicle categories and directional flows.

Sources: Clause 3.4, Clause 4.1, Clause 5.1, Clause 5.4, Clause 6.1, Clause 6.4

2Scope and Application

The scope and application of IRC 9 primarily cover the compilation and classification of traffic data for road design and analysis. As per the context, the standard includes detailed traffic census procedures capturing various vehicle types such as cars, jeeps, vans, buses, trucks, motorcycles, animal-drawn vehicles, cycles, and others. The key specification is the weekly traffic summary table (Clause 2.000) which records hourly counts for fast and slow vehicles, enabling calculation of total and average daily traffic volumes. This data is essential for road classification, design, and maintenance planning. No explicit formulas are provided in the retrieved context, but the tabulated format is critical for systematic traffic data collection and analysis.

Sources: Clause 2.000

3Selection of Census Points

The key specifications for selection of census points per IRC 9 are:

  • Census points should be located on important trunk routes like National Highways, State Highways, and Major District Roads (Clause 2.2).
  • For inter-city trunk routes, census sites must be well away from urbanized areas and commuter zones to avoid biased counts; additional stations may be added for such zones (Clause 3.1).
  • Roads should be divided into sections with approximately similar traffic volumes between points of substantial traffic change; census points are set at these section limits, typically at important towns or major intersecting roads (Clause 3.2).
  • Decisions on census point locations should be made at senior highway department levels considering the entire route's traffic pattern (Clause 3.3).
  • Census points should remain consistent for subsequent counts, with new stations added as needed (Clause 3.4).

These guidelines ensure representative, consistent, and reliable traffic data collection for planning and management.

Sources: Clause 2.2, Clause 3.1, Clause 3.2, Clause 3.3, Clause 3.4

4Frequency and Duration of Census

As per IRC 9 Clause 4, traffic census frequency and duration are specified as follows:

  • Traffic should be counted at each census point at least twice a year (Clause 4.1).
  • One count during the peak harvesting and marketing season, and the other during the lean season.
  • Each count must cover a full week, i.e., 7 consecutive days, with 24 hours counted each day (Clause 4.1).
  • Census should avoid abnormal traffic conditions like fairs or exhibitions; counts should be postponed until normal traffic resumes (Clause 4.2).

This ensures representative data capturing seasonal and daily traffic variations.

Additionally, Clause 3.4 mandates that subsequent censuses be conducted at the same locations for consistency, with new stations added as needed.

The census data recording and compilation are detailed in Clauses 5 and 6, including division of the day into three 8-hour shifts and separate recording for each travel direction.

Sources: Clause 3.4, Clause 4.1, Clause 4.2

5Recording of Data

For recording traffic census data as per IRC 9, Clause 5 specifies the procedure:

  • A day is divided into three 8-hour shifts, each with enumerators and a supervisor (Clause 5.1).
  • Traffic is recorded separately for each direction by dividing staff into two parties per shift (Clause 5.2).
  • Manual recording uses a field data sheet (Plate I) where hourly flows are tallied using the five-dash system: four vertical strokes plus an oblique stroke for the fifth vehicle (Clause 5.3 and 5.4).

Data compilation follows:

  • Daily traffic summary form (Plate II) compiles hourly data, highlighting peak hour traffic (Clause 6.1).
  • Weekly traffic summary form (Plate III) averages daily data for the week (Clause 6.2).
  • Four copies of summaries are prepared; field sheets are preserved for at least five years (Clause 6.3).
  • An index map of census site location is attached (Clause 6.4).

Tables for field data, daily summary, and weekly summary are provided in the code for systematic recording and compilation.

Sources: Clause 5.1, Clause 5.2, Clause 5.3, Clause 5.4, Clause 6.1, Clause 6.2, Clause 6.3, Clause 6.4

6Compilation of Data

The compilation of traffic census data as per IRC 9 involves systematic recording and summarizing of vehicle counts. Key points include:

  • Traffic should be counted twice yearly for a full week (7 consecutive days, 24 hours each) covering peak and lean seasons (Clause 4.1).
  • Data recording is done in three 8-hour shifts with enumerators and supervisors (Clause 5.1).
  • Traffic is recorded separately for each direction, using tally marks in a five-dash system for hourly counts (Clause 5.2, 5.4).
  • Daily traffic summary sheets compile hourly data, highlighting peak hour traffic for fast and slow vehicles (Clause 6.1).
  • Weekly traffic summary forms aggregate daily summaries to calculate average daily traffic for the week (Clause 6.2).
  • Four copies of summaries are prepared for record and distribution; field data sheets are preserved for at least five years (Clause 6.3).
  • An index map showing census site location is attached to summaries (Clause 6.4).

The key tables for data compilation include:

PERIODDATEHOURCARS, JEEPS, VANSBUSESTRUCKSMOTOR CYCLES, SCOOTERSTOTAL FAST VEHICLESANIMAL DRAWN VEHICLESCYCLESOTHERS (SPECIFY)TOTAL SLOW VEHICLESREMARKS

This structured approach ensures consistent, accurate traffic data for planning and maintenance.

Sources: Clause 2.000, Clause 3.4, Clause 4.1, Clause 5.1, Clause 5.2, Clause 5.4, Clause 6.1, Clause 6.2, Clause 6.3, Clause 6.4

7Traffic Census Field Data Sheet

The IRC 9 code specifies detailed procedures and forms for Traffic Census Field Data Sheets as follows:

  • Frequency & Duration: Traffic counts must be done twice yearly (peak and lean seasons), each for 7 consecutive days, 24 hours/day (Clause 4.1).

  • Data Recording: A day is divided into three 8-hour shifts with enumerators recording traffic separately by direction using tally marks in a five-dash system (Clause 5.1 to 5.4).

  • Field Data Sheet: Records hourly vehicle counts by categories such as cars, buses, three-wheelers, motorcycles, animal-drawn vehicles, cycles, and others. Each hour's data is tallied and totaled (Clause 5.3 and Plate I).

  • Compilation: Daily summaries (Plate II) highlight peak hour traffic; weekly summaries (Plate III) calculate average daily traffic. Copies are distributed to maintenance and planning authorities (Clause 6.1 to 6.3).

  • Additional: An index map of census sites is attached to summaries (Clause 6.4).

This structured approach ensures consistent, comprehensive traffic data collection and reporting.

Sources: Clause 3.4, Clause 4.1, Clause 5.1, Clause 5.3, Clause 5.4, Clause 6.1, Clause 6.2, Clause 6.3, Clause 6.4

8Traffic Census Daily Traffic Summary

The IRC 9 code specifies the following key points for Traffic Census Daily Traffic Summary:

  • Traffic counts must be conducted twice yearly at the same census points, once in peak and once in lean season, each for 7 consecutive days and 24 hours per day (Clause 4.1).
  • Data recording divides the day into three 8-hour shifts, with separate enumerators for each direction of travel (Clause 5.1, 5.2).
  • Traffic volume is recorded hourly using tally marks in a five-dash system (Clause 5.4).
  • Daily traffic summary sheets compile hourly data, highlighting peak hour traffic for fast and slow vehicles (Clause 6.1).
  • Weekly traffic summary sheets aggregate daily summaries to calculate average daily traffic for the week (Clause 6.2).

The key tables for recording and summarizing traffic are:

Traffic Census Field Data Sheet (for hourly vehicle counts by type and direction)

Traffic Census Daily Traffic Summary (hourly totals for fast and slow vehicles, up and down directions)

Traffic Census Weekly Traffic Summary (aggregates daily data into weekly totals and average daily traffic)

These forms include columns for vehicle categories such as cars, buses, trucks, motorcycles, animal-drawn vehicles, cycles, and others, with space for remarks and weather conditions.

This systematic approach ensures consistent, comprehensive traffic data collection and reporting as per IRC 9.

Sources: Clause 3.4, Clause 4.1, Clause 5.1, Clause 5.2, Clause 5.4, Clause 6.1, Clause 6.2

9Traffic Census Weekly Traffic Summary

The IRC 9 code specifies the following key points for Traffic Census Weekly Traffic Summary:

  • Traffic counts should be conducted twice a year, each for a full week (7 consecutive days, 24 hours/day) covering peak and lean seasons (Clause 4.1).
  • Data recording is done in three 8-hour shifts with enumerators and supervisors; traffic is recorded separately for each direction (Clause 5.1, 5.2).
  • Traffic volume is recorded hourly using tally marks (five-dash system) on field data sheets (Clause 5.4).
  • Daily traffic summaries compile hourly data, highlighting peak hour traffic for fast and slow vehicles (Clause 6.1).
  • Weekly traffic summary form compiles daily summaries; average daily traffic for the week is calculated and recorded (Clause 6.2).
  • The weekly summary table includes columns for fast vehicles (cars, jeeps, vans, buses, trucks, motorcycles, three-wheelers) and slow vehicles (animal-drawn vehicles, cycles, others), with totals and remarks (Clause 2.000).
  • Census points should remain consistent for subsequent counts (Clause 3.4).

The weekly traffic summary table format is as follows:

PERIODDATEHOURCARS, JEEPS, VANSBUSESTRUCKSMOTOR CYCLES, SCOOTERSTHREE WHEELERSTOTAL FAST VEHICLESANIMAL DRAWN VEHICLESCYCLESOTHERS (SPECIFY)TOTAL SLOW VEHICLESREMARKS

This structured approach ensures comprehensive and consistent traffic data collection and reporting.

Sources: Clause 2.000, Clause 3.4, Clause 4.1, Clause 5.1, Clause 5.2, Clause 5.4, Clause 6.1, Clause 6.2

10Preservation and Reporting of Data

The key specifications for Preservation and Reporting of Traffic Census Data as per IRC 9 are:

  • Frequency & Duration: Traffic counts must be conducted at least twice a year, once in peak and once in lean season, for 7 consecutive days and 24 hours each day (Clause 4.1).

  • Data Recording: Each day is divided into three 8-hour shifts with enumerators recording traffic separately for each direction using tally marks in a five-dash system (Clause 5.1 to 5.4).

  • Data Compilation: Daily traffic summaries are compiled from field sheets, highlighting peak hour traffic. Weekly summaries are prepared in quadruplicate for distribution to maintenance and planning authorities. Field data sheets must be preserved for at least five years (Clause 6.1 to 6.3).

  • Data Forms: The standard includes detailed field data sheets and daily/weekly summary forms capturing vehicle categories such as cars, buses, trucks, motorcycles, animal-drawn vehicles, cycles, and others (Clause 2.000 and Plates I-III).

  • Census Points: Subsequent censuses should be conducted at the same locations to maintain consistency (Clause 3.4).

This systematic approach ensures reliable, consistent traffic data collection and preservation for planning and maintenance purposes.

Sources: Clause 2.000, Clause 3.4, Clause 4.1, Clause 5.1, Clause 5.2, Clause 5.3, Clause 5.4, Clause 6.1, Clause 6.2, Clause 6.3

Popular Questions About IRC 9

?How are census points selected for traffic counting on non-urban roads?

For traffic counting on non-urban roads, census points should be selected judiciously as per IRC 9 Clause 3.1 and 3.2. The sites must be located well away from urbanized areas and villages to avoid commuter traffic influence. Roads are divided into sections with approximately similar traffic volumes between points of substantial traffic change, such as important towns or major intersecting roads. Each section should have a count station. These decisions are significant and should be made at a senior level after considering the entire route's traffic pattern (Clause 3.3).

Sources: Clause 3.1, Clause 3.2, Clause 3.3

?What is the recommended frequency and duration for conducting traffic censuses?

As per the context from IRC 9, traffic censuses should be conducted periodically as a regular feature by highway departments (Clause 1.1). The recommended frequency is focused on important trunk routes such as National Highways, State Highways, and Major District Roads (Clause 2.2). While the exact duration is not specified in the retrieved text, the census operations should be uniform nationwide (Clause 2.1) and judiciously located away from urbanized areas to avoid commuter traffic influence (Clause 3.1). The highway should be divided into sections with similar traffic volumes, and census points fixed accordingly (Clause 3.2 and 3.3). This implies that censuses are repeated at intervals sufficient to capture traffic changes on major routes, typically annually or as per planning needs, but the exact frequency and duration are not explicitly stated in the retrieved clauses.

Sources: Clause 1.1, Clause 2.1, Clause 2.2, Clause 3.1, Clause 3.2, Clause 3.3

?How should traffic data be recorded and categorized during the census?

Traffic data during the census should be recorded separately for each direction of travel and divided into three shifts of 8 hours each, with separate enumerators and a supervisor assigned to each shift, as per Clause 5.1 and 5.2. Enumerators use a field data sheet to record hourly flows by making tally marks in the five-dash system (four vertical strokes plus an oblique stroke for the fifth vehicle) for each vehicle category (Clause 5.4). The data is compiled daily and weekly using summary forms, highlighting peak hour traffic, and preserved for at least five years (Clause 6.1 to 6.3). Census points should be fixed consistently at the same locations for subsequent counts (Clause 3.4).

Sources: Clause 5.1, Clause 5.2, Clause 5.4, Clause 6.1, Clause 6.3, Clause 3.4

?What procedures are in place for compiling and summarizing traffic data?

The procedures for compiling and summarizing traffic data as per IRC 9 involve multiple steps: Traffic is recorded hourly in three 8-hour shifts by enumerators using tally marks (Clause 5.4). Data is recorded separately for each direction of travel (Clause 5.2). Daily traffic summaries are compiled from field data sheets using a prescribed form (Plate II) highlighting peak hour traffic (Clause 6.1). These daily summaries are then transferred to a weekly traffic summary form (Plate III), where average daily traffic for the week is calculated (Clause 6.2). The summaries are prepared in quadruplicate for distribution to maintenance and planning authorities, and field data sheets are preserved for at least five years (Clause 6.3). An index map showing census site locations is attached to the summary sheets (Clause 6.4). This systematic approach ensures consistent, detailed, and archival traffic data for highway planning.

Sources: Clause 5.2, Clause 5.4, Clause 6.1, Clause 6.2, Clause 6.3, Clause 6.4

?How does the standard address abnormal traffic conditions during counts?

The IRC 9 standard emphasizes that traffic census operations on non-urban roads should be conducted uniformly across the country to ensure consistency. However, the retrieved context does not explicitly address how abnormal traffic conditions during counts are handled. Typically, in traffic census practices, abnormal conditions (such as accidents, roadworks, or special events) are noted and excluded or adjusted for in the final traffic volume analysis to avoid skewed data, but this specific guidance is not found in the provided clauses.

Sources: Clause 2.1

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