Each day in the United States, approximately 9 people are killed and more than 1,000 injured in crashes that are reported to involve a distracted driver. 1 Distracted driving is driving while doing another activity that takes your attention away from driving.
This is called the post-void residual. The bladder has a approximately 500ml capacity. You should feel a desire to void at ~250ml. Urinary retention is measured by using a special type of ultrasound (bladder scan), or by inserting a bladder catheter and measuring how much urine comes out. I'm a 4th year US med student. On one of my urology rotation I asked the Sr. resident this exact question.
I was told that my bladder will hold 500cc's and that the average is 1000cc's. The normal female bladder holds about 500 or so cc's awake. Under anesthesia, a normal female bladder capacity is about 800-1000cc. I'm assuming it holds about 500 cc's when you feel like you absolutely cannot hold it any longer.