Traffic and Safety Informational Series FAQs


The goal of this project was to make available clear, concise, and consistent answers to 25 common traffic and safety questions. The information may be altered, distributed, and used as seen fit by area officials and/or transportation professionals.


Any references to the MUTCD are to the 1988 edition.

The opinions, findings, and conclusions expressed in this publication are not necessarily those of the Center for Transportation Research and Education or the Iowa Department of Transportation.

Document Format

All documents are in PDF format.

If you have any questions or comments, please call CTRE at 515-294-8103.

Traffic and Safety FAQ Sheets

Download and/or save the FAQ documents individually below, or save the entirety of the FAQs, including the summaries, here.

Individual QuestionsTwo-Page AnswersOne-Page Summaries
1. Won't a "Children at Play" sign help protect our children?answersummary
2. How many bullet holes does it take to kill a sign? (sign vandalism)answersummary
3. Won't a lower speed limit lower travel speeds and the number of accidents?answersummary
4. Why can't I have several driveways to my property where I want them?answersummary
5. Why aren't there better and longer lasting stripes on the road?answersummary
6. Why can't I place a business-related directional sign within the roadway right-of-way?answersummary
7. What factors are considered when locating, controlling, and/or marking pedestrian crossings?answersummary
8. Why isn't there a "School Bus Stop Ahead" sign everywhere a bus stops?answersummary
9. Why can't speed bumps be used on all streets to slow traffic?answersummary
10. Why do you choose the posted speed limit and where do you put the signs? answersummary
11. Can all traffic signals be timed so I receive a green light at every intersection?answersummary
12. How are signals timed to accommodate pedestrians?answersummary
13. Why can't we have stop signs to reduce speeding along my street?answersummary
14. Why can't we have a four-way stop to reduce accidents?answersummary
15. What is the harm in installing an unwarranted traffic control device?answersummary
16. Won't a traffic signal reduce accidents?answersummary
17. Safe driving procedures at railroad crossingsanswersummary
18. How do you decide where to place signs?answersummary
19. How does the county make decisions about dust control on gravel roadways?answersummary
20. When do intersections receive stop signs (two-way and four-way) and signals?answersummary
21. Why converting a four-lane street to a three-lane street may improve safety and not increase congestion?answersummary
22. Why do light poles have to be located so far from the street?answersummary
23. How does the county make decisions about paving gravel roadways?answersummary
24. Why don't we have crossing guards at all school crossings?answersummary
25. Won't a flashing yellow light draw more attention to a sign?answersummary