People in Colorado sometimes assume that they are in custody if they are pulled over by the police for operating a vehicle under the influence. However, this is not actually true. Rather than being in custody, you are simply considered to be "detained." So, what does this mean for your rights?
There are a few important things to remember, and the first is that you still are not free to go. You cannot tell the officer that you are leaving because you are not under arrest. Doing so will simply lead to your arrest because the officer already had cause to think you were under the influence before pulling you over. If you can show that you are not -- by passing the field sobriety tests, for instance -- then you may be allowed to leave, but you can't do it automatically.
Next, and more importantly, your Miranda Rights -- such as the right to remain silent -- may not be announced. The officer does not have to read them to you since you are not yet being arrested.
This is not exactly a loophole in the system, but it is a way that officers will sometimes try to get people to incriminate themselves. They can ask them questions, perhaps being straightforward and asking if they have been drinking, hoping the people will admit to it. People are sometimes caught off guard since their rights have not been read to them, and they will say things that they don't actually have to say.
After being pulled over for drunk driving, people in Colorado have to know what their rights are and what their legal options look like.
Source: Forbes, "What Should You Do If You Get Pulled over for Drunk Driving in California?" Joe Dane, Oct. 06, 2014