Does traffic fall away from the centre?
Compare traffic counts at equal distances from a town centre.
The method
Count vehicles for ten minutes at each site. One group visits the centre at 08:30 and the outer sites after 10:00.
| Site and time | Vehicles in 10 minutes |
|---|---|
| Centre, 08:30 | 185 |
| Middle, 10:00 | 94 |
| Outer, 10:30 | 65 |
Choose a presentation
Use a scatter plot if precise distances are recorded, or bars for named sites. Explain the choice against the enquiry aim.
Follow a limitation through the enquiry
- Limitation
- Location and time change together; the centre was measured during the morning rush.
- Effect on the evidence
- A high central count could reflect the time of day as well as distance. The data cannot separate those influences.
- A useful improvement
- Use coordinated teams to count at the same times at all sites, then repeat on comparable days.
Try it yourself
Explain why the proposed improvement would help this enquiry. Then identify something it would still not establish.
One possible answer
Use coordinated teams to count at the same times at all sites, then repeat on comparable days. This strengthens the evidence for the stated enquiry, but a small study still cannot represent every place or date.
Check your answer: did you address the question, use accurate evidence and explain the link?
Change the conditions
Imagine the same enquiry on another date or at another site. Which part of the method would you keep consistent? Explain why, using the enquiry aim.
What to look for
A useful answer identifies a specific measurement, sampling rule or time condition and explains how consistency makes the comparison fairer.