When a driver shows **clear symptoms of being under the influence of alcohol**, traffic officers have the responsibility to ensure that the test result is accurate.

- **First test:** The traffic officer asks the driver to blow into a device that measures the amount of alcohol in the blood.
- **Second test:** If the result is negative but the driver continues to show symptoms of having consumed alcohol, a **second test** is conducted to confirm the initial result. This is done to ensure the **accuracy** and **reliability** of the results.

This second test is crucial because, even if the first result is negative, the driver's symptoms may indicate that there is an error or that the device has not functioned correctly. Therefore, repeating the test is a measure of **safety** and **precaution** to confirm that the driver is not under the influence of alcohol.