If you're being directed to pull over by someone in an unmarked police car, you should:

• Pull over immediately regardless of location
• Slow down and drive to the nearest busy area where there are people
  Explanation:

  "If you find yourself being directed to pull over and stop by someone in an UNMARKED police car, you may drive slowly a short distance to the nearest area where there are other people, such as the next business parking lot or the next exit if you are on the interstate. This may be important if you are traveling at night and/or alone."
• Speed up and attempt to evade the unmarked car
• Ignore the direction and continue driving