DUI Checkpoints are very commonly used, though there are a lot of issues surrounding the constitutionality of these checkpoints. This has been a long debated subject in State and US Supreme Courts.
While often random stops to check license and registration and determine if a driver was intoxicated were employed by officers, this was ruled to be a violation of the driver's 4th amendment rights. It was ruled that an officer must have a reason to pull over a driver. The first court trial regarding stops was the US Supreme Court case Delaware v. Prouse (Delaware v. Prouse, (1979) 440 US 648), which states that a driver's rights are not being violated if the officer is stopping all vehicles, and not just randomly stopping vehicles. This ruling was later used to establish the neutral formula guideline for DUI checkpoints (stopping cars using a formula such as every third, fifth, etc.).
The California Supreme Court later established more rules regarding DUI checkpoints in order to protect driver's rights. The case of Ingersoll v. Palmer, 221 Cal. Rptr. 659 (App 1st Dist. 1985) established a list of guidelines that ensured these checkpoints were not too intrusive. It was also extremely important because it determined that checkpoints were administrative and its sole purpose was not criminal investigation. This distinction was extremely important because if their purpose was to find drunk drivers (and not deter them, which was the claim), they would be unconstitutional.
The court then used a balance check to make sure the public's interest was being best served. They explored the effectiveness of these checkpoints, and while roving stops would be more effective, the courts decided these checkpoints were effective enough.
The court established the Ingersoll guidelines that all DUI checkpoints must follow in order to be constitutional. The guidelines are:
- Decisions are made at the supervisory level: All administrative decisions, such as when and where to set up a checkpoint, are made by higher level supervisory officers. This ensures the checkpoints are standardized and limits the discretion of the field officers (limits differences amongst the checkpoints).
- Standardized stops: The method used to stop cars (every fifth car, tenth car, etc.) is determined by the supervisory officers and not by the field officers.
- Safety Procedures: Proper lighting, signage, and warnings must be present at and around the checkpoints. Safety of all drivers' and the officers is a top priority. As such, the formula for stopping cars must reflect traffic (ex. stopping every tenth car in heavy traffic instead of every fifth).
- Location: The location (selected by supervisors) should be a minimally intrusive, reasonable location and should reflect historical data (ex. using a stretch of road with many alcohol related accidents).
- Time and Duration: Time and duration of the checkpoint is an important issue to the public. For instance, night time would deter the most drunk drivers; however it is the most intrusive time. While this is left to the officers, it can easily be called into question during trial so it is important to be diligent.
- Easily Identifiable signs: It is important that proper signs are visible before the drivers arrive at the checkpoint, and other forms that prove the official nature of the stop must be evident (such as officer vehicles with lights on, etc.).
- Length of detention: the amount of time each person is held after suspicion of being drunk must be limited if there is no evidence. This is to protect rights as well as prevent traffic buildups.
- Advance publicity: There must be adequate advanced warning of a roadblock. It is important to minimalize the intrusiveness of the roadblock and reduce the surprise for motorists.
There are still many who believe these roadblocks are illegal search and seizures. The US Supreme court finally handed down a decision to attempt to end the debate. In the case Michigan Dept. of State Police v. Sitz, (1990), the court decided that these roadblocks serve a governmental purpose and are in the best interest of the public and as such we effective and constitutional.
The Sitz court also decided that given all of the warnings the drivers have (signs, lights, advance publicity), these roadblocks are no too intrusive. However, the dissenting opinion held that there was still not enough evidence to stop a person, even if a neutral formula was being used.
One example the dissenting opinion pointed to was an instance where 19 officers were working a roadblock that only caught two drunk drivers all night. Their argument was what these 19 officers would have deterred more drivers if they were out and not stuck at the roadblock.
The US Supreme court stated that guidelines must be used, however they did not set up those guidelines themselves, instead yielding to each state (Ingersoll in CA).
One of these guidelines, advance publicity, was determined by CA to be extremely important and was strongly recommended, however it did not require it and failure to follow this guideline wasn't grounds for dismissal (People v. Banks, (1993) 6 Cal. 4th 926).
It is important for DUI defense attorneys to understand the laws and guidelines for DUI checkpoints. There are a few defense strategies to explore. First, it is important to establish that all proper regulations were followed (keep in mind once stopped officers must follow proper guidelines for determining BAC). Second, it is important to find out if the Ingersoll requirements were followed. Lastly it would be beneficial to look at the National Highway Traffic Safety Administration (NHTSA) guidelines, since Ingersoll is not an exhaustive list of factors at a checkpoint.