Road traffic flow and pollution
The materials required for this science fair project:
- 1 highway route with a speed limit of at leaset 90km/h
- 1 video camera mounted on an adjustable stand
- sufficient video tape or memory cards
- 1 elevated location to set up the camera and to film the traffic
- 1 stopwatch
1. For this science fair project, the independent variable is the window of time allotted for monitoring the passing vehicles. The dependent variable is the average vehicle speed, volume of traffic and rate of traffic flow. This is determined by first recording the flow of traffic with the video camera, and carefully reviewing the recording. The constants (control variables) are the chosen location, the day of observation and the viewing range and angle of the video camera.
2. An elevated location is chosen along a highway. The video camera is set up using the stand and adjusted so that a 200 meter long stretch of the highway can be clearly observed in the recording.
3. The record the flow of traffic from 6:00am to 12:00 midnight. You may need to replace the tape/memory card regularly. Ensure that you do so at regular intervals (for example, after every 2 hours and 59 minutes). After the 18 hours recording is completed, retrieve your equipment and analyze your recording.
4. The recording is divided into 6 windows of 3 hours each. The time windows are 6am to 9am, 9am to 12pm, 12pm to 3pm, 3pm to 6pm, 6pm to 9pm and 9pm to 12am.
5. From the video recording the following data is collected :
a. Traffic speed – the time taken by the vehicles to travel the 200 meters is used to estimate the vehicle speed.
Speed = 60 x 200 m / (time for 200 m in minutes)
The speed of several vehicles for window of time is estimated as above and their average speed is calculated and recorded in the table given below.
b. Traffic volume – the number of vehicles on the road is used to define the traffic volume. If there were more than 300 vehicles on the road within the 3 hour window, the traffic volume will be recorded as high, otherwise it will be considered as moderate.
c. Traffic flow –continuous movement of traffic will be considered smooth while traffic that moves, stops and idles frequently is considered as “start-stop”.
6. The definitions given in procedure 5 are further translated into numerical values on the following assumptions:
a. Traffic speed
1- speed between 55 and 75 km/hour (most efficient with the least amount of emission)
2- other speeds (less efficient and result in higher emissions)
b. Traffic volume
1- moderate traffic flow (less vehicles on the road and less emission)
2- heavy traffic flow (more vehicles on the road and more emission)
c. Traffic flow
1- smooth flowing traffic (consumes less fuel and less emission)
2- start-stop traffic (consumes more fuel and more emission)
A pollution index for each time slot is calculated by adding up the scores for all three sections (speed, volume and flow).
Adult assistance required. Be careful when you’re on the road. Choose an observation point that is safe and observe all road safety rules.