Understand that the police want you to help them make their case against you stronger. By performing field tests, you are simply helping the police manufacture evidence against you. Be aware that they fully intend on using this evidence against you in court. Therefore, taking an eye test, balancing test, or any other evaluation on the street is usually not a good idea. Most experts agree that police officers are not well trained enough to accurately interpret the symptoms observed while administering these street evaluations. This doesn’t mean that you need to be rude or nasty to an officer if he asks you to do a field sobriety test. Instead, it's a good idea to respectfully decline all tests on the roadside.