Bypassing Probable Cause

Ok...after much research surrounding searches and seizures, I stumbled across a fact that seems to grant an enormous amount of power to police and I would like a lawyer or someone with more legal knowledge than myself to tell me if I'm right.
Person X is traveling at 45mph in a 35mph and is pulled over by a police officer. The stop is legit and routine, with the exception that the police officer decides to place Person X under arrest for this moving violation, knowing full well that, technically, any person may be placed under arrest for even these minor violations. (A recent Supreme Court decision upheld the arrest of a woman for a seatbelt violation) Thus, following this arrest, the police officer is allowed to search Person X and the passenger compartment of the vehicle. Following from this, is it logical to assume that police can bypass any type of probable cause by arbitrarily placing drivers under arrest simply to search their car? Or, is there some sort of "good faith" clause built in that I've missed which would exclude any evidence as a result of a search that was manipulated?
I'm looking forward to your replies....
Dr. J

This is an interesting question. It might take me a couple days to get back to ya on this. I wanna do some research. Do you happen to have the case name or cite for the supreme court case you're referring to?

I'm not sure what you mean by "...arbitrarily..".
At the beginning of your scenerio the person is arrested for speeding, not for an arbitrary reason.
I too would like to have the case citation to review the opinion(s).

Well, I'm not sure which case you want, as the other thing that made me think about it was the Supreme Court ruling in Atwater vs. Lago Vista, 99-1408. From this ruling, and following rules governing the police's power to search subsequent to arrest, I immeidately became concerned about their power.
My use of the word arbitrarily was meant not the type of arrest, but the decision to make the arrest, take the person into custody, and eventually perform a search without the required probable cause.
As a side note, I should note that the speeding case above is not exclusive....some states do not allow for arrests unless the violation in punishable by time in jail. So, for your answer to my question, assume that the offense committed IS something the person can be arrested for.
Dr. J

I have a basic answer for your ?
It is legal for the police to arrest you for even the most minor infraction. And yes they can Inventory your vehicle which allows them to look everywhere in, on, under, behind, etc. even inside the frame rails if they want to. Most of the time if they think you've got goodies in the car they will just run a dog through the car. BUT....If the cop doesn't usually arrest people for the violation then you probably have a way to get out the charges (if they found something and charged you). But most of the time if you run across a "smart" cop who understand the laws very well, your screwed. Sorry
With this scenario there way too many different scenarios to consider to answer this type of question without writing a 50 page paper on the subject.
I hope I've answered your question.

Police discretion in general is fairly arbitrary, and there's not much to be done about it in cases, as you've outlined, where state law allows a person to be arrested.(Your's truely was once arrested and searched for speeding in Iowa).
A search incident to a lawfull arrest is not without limitations(You still have basic 4th amendment rights). Absent probable cause, an arrest for speeding would not support a search of the trunk or frame of a vehicle, for example. Passenger comparment searches would be limited to "reasonable", a vague standard I know, but courts prefer to decide on a case by case basis, and there aren't a lot of hard rules.

I agree if only it were a search incident to arrest. If the officer has the vehicle towed, they can do was is called an inventory of the vehicle. Which includes and is not limited to just the passenger compartment or the trunk.