Blood tests have traditionally proven to be more accurate than breath tests
when police are checking to see if a driver is over the legal limit. That
limit has been set for most drivers at 0.08—it’s only different
in some cases for commercial drivers and underage drivers. Though blood
tests are better, the breath test is simple and effective, and many mobile
devices can be used by police on the scene to decide if a DUI is warranted.
However, it is very important to note that a breathalyzer must be calibrated
correctly to provide accurate results. Even the slightest degree off from
perfect can make a huge difference. If a driver comes in at 0.07, he or
she is allowed to go without issue, but, just .02 higher, at 0.09, that
driver will be given a DUI.
The officers are supposed to do regular maintenance on their
breath test devices, and they are supposed to calibrate them on a predetermined schedule.
This is different for the various makes and models out there, but it is
crucial that the officers follow that schedule or they can’t know
that the unit is giving them a real reading. While it may be close, as
is noted above, that it is not good enough.
If you have been given a DUI after a breath test, you have the right to
challenge the test if you believe you should do so. One of the big reasons
people are put in these challenges in Maryland is because they think that
the breathalyzers were neglected and not calibrated when they should have
been, leading to inaccurate readings and fraudulent chargers.