How to conduct a traffic volume survey? A detailed explanation from the basics to implementation methods!

How do I start a traffic survey?

Do you have any questions like that?

You may have seen surveyors standing at intersections with a counter in hand. In reality, there are various methods for traffic volume surveys, and they need to be used depending on the purpose and location.

This article provides an easy-to-understand explanation for those who are planning to conduct a traffic volume survey or who want to review their methods.

What is a traffic survey?

Traffic volume surveys are surveys that count the number of cars and people passing through a road or intersection to understand traffic flow and congestion. They are often conducted by government agencies, local governments, consulting firms, construction companies, etc. for urban planning and traffic development, and are one way of "visualizing" road performance and usage.

Data obtained from traffic volume surveys is used in a variety of situations, including road development plans, congestion countermeasures, traffic signal reviews, and the construction of new facilities. The survey results are directly linked to real-world social infrastructure, such as predicting the impact of construction projects and improving existing traffic environments to make them safer and more comfortable.

For example, it can be used to make decisions such as, "This intersection is always congested in the morning, so let's change the intervals between traffic lights," or, "We're building a large facility, but will this be enough to put strain on the surrounding roads?"

Traffic volume survey data is also extremely useful as a resource for analyzing the causes of frequent traffic accidents and for developing safety measures for pedestrians and cyclists.

The basis for traffic volume surveys in Japan is the Road Traffic Census. This is a large-scale survey conducted once every five years by the Ministry of Land, Infrastructure, Transport and Tourism, with the aim of comprehensively understanding the traffic conditions of vehicles and pedestrians on roads across the country. Census data is also used to design individual traffic volume surveys conducted by local governments and companies, and to evaluate the results.

The Road Traffic Census is an important basic resource for understanding long-term traffic trends, and by combining this nationwide survey data with detailed on-site survey results, it is possible to implement more accurate and effective traffic measures.

Why are you investigating?

The scale and method of the survey will change depending on the purpose. By clarifying the purpose of the survey, it will be easier to determine the necessary information and appropriate methods.

Common purposes include:

• To be used in road and intersection development plans

• To understand the traffic congestion situation and take measures

• To investigate the actual traffic situation of vehicles at specific locations

• Analysis of vehicle type (passenger car/bus/truck, etc.) and traffic direction

• Traffic impact surveys for construction of commercial facilities, schools, logistics facilities, etc.

• Understanding traffic conditions related to disaster prevention and evacuation plans

• Analysis of congestion around tourist spots and event venues

  
  

The observation period is also important. For example, there may be cases where you want to compare traffic volume not only on weekdays but also on weekends and holidays, or you may want to take seasonal factors (such as summer vacation or the New Year holidays) into account.

What methods are available? Compare the main survey methods!

There are various methods for traffic volume surveys, ranging from manual counting to analysis using the latest AI technology.

Comparison table by method

Detailed explanation of each method

Manpower counting

Characteristics : This is the most basic and time-honored method, in which investigators stand at intersections and other locations and visually count vehicles and pedestrians using special counters and checklists. It can be adapted flexibly to suit the location and situation, and detailed data can be obtained that is tailored to the on-site situation. It is particularly effective in cases where machines cannot fully handle the situation, such as when detecting sudden changes in the situation or special vehicles.

merit :

• Flexible response possible through visual inspection

• You can instantly grasp detailed information such as the type of vehicle and direction

Cons :

• High cost and not suitable for long-term surveys

• Visibility is reduced at night or in bad weather, reducing accuracy.

• Risk of miscounting due to human error or fatigue

Video analysis (automatic)

Features : This method uses the latest technology to analyze video footage recorded by cameras using AI, and has become increasingly popular in recent years. It can accurately recognize the type and movement of target vehicles based on specific rules, thereby reducing manpower and improving efficiency. Camera footage can be saved and reviewed, making it flexible enough to easily accommodate remote monitoring and data collection.

merit :

• AI counting reduces manpower

• Records are kept so they can be verified later.

• High accuracy of around 95% during the day

Cons :

• Accuracy is slightly reduced (80-90%) at night or in bad weather

• Accuracy varies depending on the camera installation location and angle

• The installation cost is a little high

Video analysis (manual)

Features : This method involves reviewing footage taken on-site at a later date in an office or other location, and counting objects visually. Recorded footage can be paused and rewound while reviewing, allowing for more careful and accurate analysis than real-time. It is also suitable for small-scale surveys and for identifying special observation items (such as those using walking aids).

merit :

• You can check the video multiple times to prevent oversights

• Flexible response to sudden surveys without the need for personnel on-site

Cons :

• Easily affected by video quality (backlighting, blur, resolution, etc.)

• Similar to manual counting, it requires a large human load

• Long-term analysis requires a considerable amount of manpower and time

Sensor type (optical)

Features : This method uses non-contact sensors such as infrared and lasers installed in a portable traffic counter to automatically detect vehicles and count the number and direction of passing vehicles. Installation is completed by attaching a simple device to a tripod or pole, so it can be set up in a short time and is used in narrow alleys, temporary roads, construction sites, etc.

merit :

• Relatively easy to install and suitable for 24-hour continuous measurement

• Contactless and safe, ideal for short-term work

Cons :

• Susceptible to weather conditions such as rain, snow, and fog

• There may be lighting restrictions at night or in tunnels

Sensor type (vibration type)

Features : This method uses sensors on portable traffic counters installed on the road to detect and count minute vibrations and impacts when vehicles pass. This method is also analyzed using AI. As most models are portable and do not require an external power source, they are easy to set up and remove, and survey costs are kept low. They offer stable accuracy day and night, and are used for short-term surveys such as those for public works projects. A typical example is the "Ototorkun" developed by Onkyo Corporation, which is said to have an analysis accuracy of 95% (according to a survey company).

merit :

• Stable high accuracy day and night (nominal 95% accuracy (according to research company))

• AI counting reduces manpower

• Easy to install, just install on the ground, suitable for 24-hour continuous measurement

• Some models do not require an external power source, making them highly portable

Cons :

• Accuracy may be reduced in bad weather

• Accuracy may be reduced when measuring multiple lanes

What and how do you measure it?

The main data obtained from traffic count surveys are:

• Vehicle type (passenger car/light car/bus/freight vehicle/bicycle, etc.)

• Direction of travel (e.g. east to west, south to north, etc.)

• Number of passing vehicles (by time zone and lane)

• Survey time (peak hours, 12 hours, 24 hours, etc.)

• Traffic congestion conditions (average vehicle speed, waiting time at traffic lights, etc.)

• Pedestrian and bicycle traffic volume

• Traffic density and dwell time at specific points

  
  

Based on this information, traffic flow and congested areas can be visualized, which will be useful for identifying issues and planning future transportation policies.

Key points for a successful investigation

To ensure that traffic volume surveys are carried out smoothly and effectively, the following points are crucial:

• ✅ Clarify the purpose : Why are you conducting the survey? What information do you need? The purpose will also clarify the scale and items of the survey you need.

• ✅Select the appropriate method : Choose the most appropriate method depending on the survey location, budget, personnel structure, and accuracy requirements. For example, a sensor method (vibration method) for a short-term survey, or video analysis if long-term recording is required, making a case-by-case selection is important.

• ✅Confirm installation and observation times in advance : It is necessary to understand peak traffic times and seasonal and day-of-the-week changes, and to create an efficient survey plan.

• ✅Consider using multiple methods in combination : When high accuracy is required or human resources are limited, combining video analysis and sensor methods can achieve both accuracy and efficiency.

• ✅ Consider how to utilize the data : The purpose of a survey is not to obtain data itself; the key to success is to anticipate in advance how that information will be used to inform decisions and policies.

• ✅ Prepare backup days and alternative methods : Planning backup days and alternative methods in case of bad weather or equipment problems will increase the reliability of your survey.

• ✅Check for permission and notification : Installation on public roads or within facilities may require prior permission from the road administrator, police station, or facility administrator.

Traffic volume surveys are a means, so choose the method that best suits your purpose

There are many different methods for traffic volume surveys, each with its own strengths and weaknesses.

"I want to measure accurately." "I want to keep costs down." "I want to use as few people as possible."

The best research method will vary depending on what you value.

Traffic volume surveys are merely a means to an end, and the goal is to improve the traffic environment and contribute to urban development. The survey results are directly linked to social infrastructure such as road improvements, signal design, and facility placement.

That is why it is important to choose a method that suits your purpose and conduct your research efficiently and without waste.

If you are unsure of what to do, it is effective to refer to past cases and the advice of local governments and specialist companies. Surveys are not just about grasping numbers; they are the first step in visualizing the "flow of people and vehicles." They are an essential process when considering the future of transportation.

In the future, traffic volume surveys are expected to continue to evolve with the use of AI technology, cloud integration, real-time analysis, etc. By keeping up with the latest technological trends, we will be able to achieve more efficient and highly accurate surveys.

Introducing Ototorkun

For those who want to conduct traffic volume surveys more easily and accurately, we recommend our portable traffic counter, "Ototorkun." It takes just a few minutes to set up, and can count vehicle passage with high accuracy, day or night. It works well in environments where video recording or long-term manual observations are difficult, and survey companies have reported that its analysis accuracy is 95%.

For more information , click here.