When a driver is subjected to a breathalyzer test and a level of **0.3 milligrams per liter in exhaled air** is detected, they have the right to request a second test. This second test is important to confirm the results of the first and ensure there are no errors.

- **Test procedure**: The initial test is performed by blowing into a device that measures the amount of alcohol in the exhaled air. If the result is positive, a second test must be conducted to confirm the result.

- **Time between tests**: It is necessary to wait at least **10 minutes** between the first and second test. This waiting time is crucial to ensure the accuracy of the results and allow any alcohol residue in the mouth to dissipate.

- **Right to a second test**: The driver has the right to request this second test if they disagree with the initial results. This is part of a standard procedure to ensure fairness and accuracy in detecting alcohol in drivers.

Therefore, the correct answer is that a second test can indeed be requested, but there must be an interval of at least 10 minutes between both tests.