If you lose a DMV hearing, your remedy is to file a writ petition in the Superior Court. However, these are very tricky and the issues are very limited. If you are considering doing this, you should consult with counsel to make sure that you have a viable issue.
You can request departmental review, which has very little chance of success. If you are within 15 days of the date of decision by the DMV hearing officer, you can make this request by sending DMV $120.00 and requesting departmental review for action taken pursuant to Vehicle code section 13353 or 13353.2. Having an attorney for this is usually a good move.
The other way to appeal is to go through the Superior Court. You have 34 days from DMV decision to do this, or if you've requested the above departmental review your time to request Superior Court help through the writ process extends to over 90 days. This should not be attempted without an attorney, or without consulting a DUI lawyer who does these writs first.
In general, once administrative remedies have been exhausted, courts can reverse decision of administrative agencies only on a showing the the administrative ruling was "arbitrary and capricious". That seems to happen rarely, if ever.
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