# Fundamentals of Transportation/Sight Distance/Additional Problems

1. What happens if an accident is caused by poorly designed roads? → Lawsuits
2. Explain Stopping Sight Distance again → = perception reaction distance + braking distance
3. Isn’t 200 m long distance for braking → Yes unless very high speed on very slick surface (or going downhill).
4. Is higher coefficient of friction used in road design? → Not too often, more often taken as a function of materials and construction, and wear and tear on road (older roads have less friction).
5. Does coefficient of friction properly account for the ways cars brakes work and the manner in which drivers apply the brakes?
6. Are stopping distance (related to accident reconstruction) admissible as evidence in court? Would this be by a licensed professional engineer? → Yes
7. How close are accident reconstruction calculations to be actual accidents? → Should be on average correct …
8. For stopping distance, why don’t we have a factor to include vehicle size and weight?
9. Why would the grade “G” be positive in the stopping distance equation? What would the sign be in the Stopping Distance Equation. What does a negative grade mean if you are were assuming to be going downhill?
10. Describe the interaction between gravity and friction when going up or downhill. Is friction helped or hindered?
11. Why can cosine and sine be ignored in calculations? --> Small angle approximations.
12. What are the steps in accident reconstruction
13. If you have an accident reconstruction problem, do you incorporate grade when finding friction? Yes, but the grade is known.
14. How are skid marks useful in determining initial speed of vehicle?
15. What affects the friction force?
16. What can stopping distance measure be used for?
17. What effect does grade have on stopping distance?
18. What if more or less skid-marks found at an accident scene. How are averages computed when distances are far apart?
19. What is average perception reaction time given by AASHTO
20. What is the maximum grade of a driveway?
21. What type of braking is assumed in the stopping distance equation?
22. When an object is sliding on an inclined surface, what two forces are operating on it?