Improper temporary traffic control can result in collisions with serious injury, death and subsequent litigation against government entities, contractors, sub contractors, and utility companies. By their nature, these zones create obstacles with which motorists can collide, divert motorists' attention from the driving task, and expose workers to hazardous situations.

The National Highway Traffic Safety Administration (NHTSA) reviewed over 1000 fatalities involving temporary traffic control situations and developed a list of defects found to have been contributing factors. Here's a few of the key factors.

1. Failure to have and then follow the approved traffic control plan.
2. Failure to use flaggers who have been adequately trained in safe temporary traffic control practices.
3. Failure to protect motorists from pavement edge drop-offs.
4. Failure to obtain proper permits to work on public right-of-way
5. Improper advance warning sign spacing and use of non-standard traffic control devices.
6. Failure to remove conflicting pavement markings.
7. Placement of temporary traffic control devices where they limit sight distance.
8. Failure to inspect temporary traffic control zones to insure that all traffic control devices are properly maintained and positioned in accordance with the traffic control plan.

The last 10% of the interview is often the most important as this is when the greatest amount of information, per unit of time, is exchanged. At a minimum you should ask the person if there is anything else they want to tell you or if they have any questions.

Asking interviewees, "are there any questions you thought I might ask that I didn't?" always generates an interesting reply. Remember you can only ask questions about what is known, and this question frequently uncovers information that the investigator simply had no knowledge of.

When closing, the witness should be assured that the interview has been valuable. Thank them and tell them what will happen now. They should be encouraged to contact the investigator at a later date if they want to provide additional information or wish to enquire about the progress of the investigation. Even better, put the onus on yourself to call them in a few days to inquire about their welfare. This is frequently rewarded with additional information that the interviewee recalled after leaving the interview. People will seldom ever call the investigator. Make that call!

Investigation Axioms

AXIOM: an established or widely accepted principle