How can you tell when you need to bring your vehicle in for its next vehicle roadworthiness test?

You answered correctly. You can find out when your vehicle is due for its next roadworthiness test by checking both the inspection tag on the rear license plate and the entry in the registration certificate Part I. The inspection tag shows the month and year of the next inspection, while the registration certificate Part I also has the relevant date recorded. The operating manual does not provide this information, so only these two sources are reliable. Remember this for future questions: always rely on the inspection tag and the vehicle registration certificate for official test dates.