In Michigan, checkpoints were challenged on these grounds. The Michigan court found that the checkpoints did, indeed, violate the Fourth Amendment. The police appealed the decision , and the case reached the United States Supreme Court.

The Rehnquist Court narrowly overturned the Michigan decision in 1990 (Michigan v. Sitz), arguing that the public benefit of getting drunk drivers off the road outweighed the “minor” infringement on civil liberties. It acknowledged, however, that the use of checkpoints constituted a violation of the Bill of Rights. Dissenting opinions argued that the amendment does not provide for any exceptions, that the court did not adequately balance the interests of the government and those of the individual, as well as pointing out several other crucial flaws in the ruling.

The Court also reasoned that in order to avoid excessive intrusion on the part of the government, guidelines must be established. They left it to the states to determine what those guidelines would be. In California, our state Supreme Court (Ingersoll v. Palmer) said that checkpoints must meet the following requirements:
•Supervisors (and not field officers) must decide when and where to hold checkpoints
•“A neutral mathematical formula, such as every driver, or every third, fifth, or tenth driver should be used in determining who to stop at the roadblock.” (This is to avoid arbitrariness and profiling on the part of the officers.)
•Warning lights and signals must be highly visible, for the safety of motorists
•Locations and times of checkpoints must be reasonable The “officialness” of checkpoints must be clearly indicated
•Drivers should not be detained longer than necessary to determine whether they are impaired. If they show no signs of impairment, they should be released immediately.
•Advance public notice of checkpoints must be given. (This is designed to increase the deterrent effect, minimize intrusiveness, and to help establish the “officialness” of the checkpoint.)

The California ruling also held that motorists should not be stopped for simply attempting to avoid the checkpoint, and that if officers do not follow these guidelines, the evidence they obtain is not admissible in court.¹

One would think that, given the slim majority in the Supreme Court ruling, along with the strict guidelines established by our own state's court, law enforcement would be very careful in its use of sobriety checkpoints.

However, even the mainstream media's reporting on the checkpoints shows us that this is not the case.

Just last week, the Modesto Bee reported that in Turlock, California, police use "chaser cars"² to pursue motorists who seek to exercise their freedom to avoid checkpoints.

Another problem is the de facto use of checkpoints as dragnets. While the California Supreme Court approved the use of checkpoints as a deterrent to drunken driving, it was careful not to approve their use to actually gather evidence for use in prosecutions. This is one of the reasons checkpoints initially passed Constitutional muster.

However, police are now using checkpoints, which some of the more savvy agencies are referring to as "traffic safety" checkpoints, for all manner of inspections, including everything from simple vehicle code violations such as cracked windshields and burned-out bulbs, to the more serious driver's license and insurance inspections, and even inquiries into potential warrants, for drivers and passengers alike.

It begs the question: Is it legal for police to use a tactic approved to combat drunk driving to persecute unlicensed drivers, when said approval mentions nothing about licensing?³

Now we have to face another reality: In today's California, “unlicensed driver” tends to be synonymous with “undocumented immigrant.” In many letters to the editor of local mainstream newspapers, writers who are apparently ignorant of the law's limitations defend the tactic on the grounds that people without papers should not only not be driving, but should not be in the country. This argument, which highlights the arguments of the immigrant advocates that the checkpoints are a civil rights violation, does nothing do justify the agencies' use of checkpoints to discover unlicensed drivers when the law only permits them to detect impairment.

This is to say nothing of the effects of impoundment on immigrants—the cost, inconvenience, and heartache of having to pay a heavy ransom to a towing company, when they are already among our society's most exploited. It does, however, raise the question of which companies are doing the towing and impounding, as well as how they secure their exclusive contracts with the city. They didn't make any contributions to the campaigns of city councilmembers or mayors, did they? The question merits investigation.

So while anti-illegal immigration activists may clamor for law enforcement at the border, their disregard for respect of the law at these checkpoints belies their true motives.

Finally, I would like to address what I believe to be the most sinister aspect of police checkpoints. Despite all the rhetoric about public safety, their primary result is the normalization of an intrusive police presence in our daily lives. We see police action so often that we don't even question it, much less protest in defense of our most essential rights. We put up with one infringement with the belief that it is for the greater good. But where is the line? When does a “minor infringement” shift from a mere inconvenience to become a severe violation? How many people, unaware of the laws governing checkpoints, have been inconvenienced only to allow themselves to be checked for their licenses, insurance papers, criminal history, and when agencies have 287(g) agreements with ICE, their immigration status? How far into their lives will people allow law enforcement to intrude, whether on the road, at the airport, or in private communications such as e-mail and telephone conversations, as permitted by the PATRIOT Act and the Violent Radicalization and Homegrown Terrorism Prevention Act of 2007? If the anti-immigrant activists have it their way, people will put up with any measure that stops what they term “the invasion.” But I hope that true patriots will stand up for the rule of law on the streets of their communities and against police intrusion into their privacy.
____________________________
1. Kavinoky, Darrin. "Legal Requirements of Roadblocks: The Ingersoll/Palmer factors." June 8, 2006. http://www.goinglegal.com/article_61345_18.html

2. Guerra, Patty. "As holidays near, state agency declares 'the year of the checkpoint'". Modesto Bee, December 18, 2009. http://www.modbee.com/local/story/977868.html

3. In a non-DUI-related case, the US Supreme Court has legitimated the use checkpoints to check the licensing of drivers. Nonetheless, there is also a California Vehicle Code statute that prohibits stopping motorists on the mere suspicion that they are unlicensed. This contradiction can be summed up by explaining that license checkpoints, as described by the court, are equally applicable to all motorists (that is, they are required to ask all drivers for licenses, and the probable cause requirement is much lesser when just verifying licenses), whereas it is nearly impossible to establish probable cause for not having a license, and attempts to do so would amount arbitrary stops and profiling.

There is no need to stop every car and driver. A simple roll of the dice, to decide if every driver or every 6th car will be stopped. There should be a through lane and an inspection lane. Checkpoints need to happen in poor and rich neighborhoods. Data must be collected and made available to the media for publication. Checkpoints should randomly be combined with ICE participation and or Military Police as needed. Checkpoints should be established for: DUI, license, insurance, smog, drug transportation, mechanical safety, etc.

In the early days of the automobile the Court created an exception for searches of vehicles, holding in Carroll v. United States 55 that vehicles may be searched without warrants if the officer undertaking the search has probable cause to believe that the vehicle contains contraband. The Court explained that the mobility of vehicles would allow them to be quickly moved from the jurisdiction if time were taken to obtain a warrant. 56

Initially the Court limited Carroll's reach, holding impermissible the warrantless seizure of a parked automobile merely because it is movable, and indicating that vehicles may be stopped only while moving or reasonably contemporaneously with movement. 57 Also, the Court ruled that the search must be reasonably contemporaneous with the stop, so that it was not permissible to remove the vehicle to the stationhouse for a warrantless search at the convenience of the police. 58

The Court next developed a reduced privacy rationale to supplement the mobility rationale, explaining that ''the configuration, use, and regulation of automobiles often may dilute the reasonable expectation of privacy that exists with respect to differently situated property.'' 59 '''One has a lesser expectation of privacy in a motor vehicle because its function is transportation and it seldom serves as one's residence or as the repository of personal effects. . . . It travels public thoroughfares where both its occupants and its contents are in plain view.''' 60 While motor homes do serve as residences and as repositories for personal effects, and while their contents are often shielded from public view, the Court extended the automobile exception to them as well, holding that there is a diminished expectation of privacy in a mobile home parked in a parking lot and licensed for vehicular travel, hence ''readily mobile.'' 61

The reduced expectancy concept has broadened police powers to conduct automobile searches without warrants, but they still must have probable cause to search a vehicle 62 and they may not make random stops of vehicles on the roads, but instead must base stops of individual vehicles on probable cause or some ''articulable and reasonable suspicion'' Supp.5 of traffic or safety violation orsome other criminal activity. Supp.6 By contrast, fixed-checkpoint stops in the absence of any individualized suspicion have been upheld. 64 Once police have validly stopped a vehicle, they may also, based on articulable facts warranting a reasonable belief that weapons may be present, conduct a Terry-type protective search of those portions of the passenger compartment in which a weapon could be placed or hidden. 65 And, in the absence of such reasonable suspicion as to weapons, police may seize contraband and suspicious items ''in plain view'' inside the passenger compartment. 66

Once police have probable cause to believe there is contraband in a vehicle, they may remove it from the scene to the stationhouse in order to conduct a search, without thereby being required to obtain a warrant. ''[T]he justification to conduct such a warrantless search does not vanish once the car has been immobilized; nor does it depend upon a reviewing court's assessment of the likelihood in each particular case that the car would have been driven away, or that its contents would have been tampered with, during the period required for the police to obtain a warrant.'' 67 The Justices were evenly divided, however, on the propriety of warrantless seizure of an arrestee's automobile from a public parking lot several hours after his arrest, its transportation to a police impoundment lot, and the taking of tire casts and exterior paint scrapings. 68 Because of the lessened expectation of privacy, inventory searches of impounded automobiles are justifiable in order to protect public safety and the owner's property, and any evidence of criminal activity discovered in the course of the inventories is admissible in court. 69

It is not lawful for the police in undertaking a warrantless search of an automobile to extend the search to the passengers therein. 70 But because passengers in an automobile have no reasonable expectation of privacy in the interior area of the car, a warrantless search of the glove compartment and the spaces under the seats, which turned up evidence implicating the passengers, invaded no Fourth Amendment interest of the passengers. 71 Luggage and other closed containers found in automobiles may also be subjected to warrantless searches based on probable cause, the same rule now applying whether the police have probable cause to search only the containers 72 or whether they have probable cause to search the automobile for something capable of being held in the container. 73

http://caselaw.lp.findlaw.com/data/constitution/amendment04/03.html#4

I can see an opportunity to turn these hassels into a public spectacle that would, how do you say, burn the idea into its own grease spot?
Fun Fantasy and Confusion with a few video cams and some pre-staged situations? hmmmmm? What a wonderful target of opportunity with the clown brigades.
It could be effective public relations if done correctly and cleverly.
A great embarrassment for these violations of constitutional limits of due process, 6th privacy 4th and 1st and 5th amendment right to not speak and right to not self incriminate.

It is well known that these checkpoints are mainly revenue-enhancing ploys to nab poor people, and now undocumented workers.
Thanks god for Twitter and the Internet. Human beings have the right to know that they are about to be led into an inspection.

yes but by the time you see that warnings it's too late
your busted