# Fundamentals of Transportation/Sight Distance/Additional Problems

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## Additional Questions[edit]

- What happens if an accident is caused by poorly designed roads? → Lawsuits
- Explain Stopping Sight Distance again → = perception reaction distance + braking distance
- Isn’t 200 m long distance for braking → Yes unless very high speed on very slick surface (or going downhill).
- 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).
- Does coefficient of friction properly account for the ways cars brakes work and the manner in which drivers apply the brakes?
- Are stopping distance (related to accident reconstruction) admissible as evidence in court? Would this be by a licensed professional engineer? → Yes
- How close are accident reconstruction calculations to be actual accidents? → Should be on average correct …
- For stopping distance, why don’t we have a factor to include vehicle size and weight?
- 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?
- Describe the interaction between gravity and friction when going up or downhill. Is friction helped or hindered?
- Why can cosine and sine be ignored in calculations? --> Small angle approximations.
- What are the steps in accident reconstruction
- If you have an accident reconstruction problem, do you incorporate grade when finding friction? Yes, but the grade is known.
- How are skid marks useful in determining initial speed of vehicle?
- What affects the friction force?
- What can stopping distance measure be used for?
- What effect does grade have on stopping distance?
- What if more or less skid-marks found at an accident scene. How are averages computed when distances are far apart?
- What is average perception reaction time given by AASHTO
- What is the maximum grade of a driveway?
- What type of braking is assumed in the stopping distance equation?
- When an object is sliding on an inclined surface, what two forces are operating on it?
- When is the road grade equal to 0.
- Why is accident reconstruction performed? How does it work?