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The cross section of a typical highway has a latitude of variables to consider such as the volume of traffic and the character of the ______.
The cross section of a typical highway has a latitude of variables to consider such as the volume of traffic and the character of the ______.
traffic
A 7.20 meters wide pavement has 18% less accident records compared with pavement narrower than ______ m wide.
A 7.20 meters wide pavement has 18% less accident records compared with pavement narrower than ______ m wide.
5.50
According to accident records, there was no difference between the ______ meters and the 7.20 meters wide pavement.
According to accident records, there was no difference between the ______ meters and the 7.20 meters wide pavement.
6.60
For the 6.00 m, 6.60 m, and 7.20 meters wide pavement with 2.70 to 3.00 m wide shoulder, recorded accident decreases by ______% compared to 0 to 0.60 m wide shoulder.
For the 6.00 m, 6.60 m, and 7.20 meters wide pavement with 2.70 to 3.00 m wide shoulder, recorded accident decreases by ______% compared to 0 to 0.60 m wide shoulder.
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The method of plotting the existing cross section is used for the purpose of obtaining quantities such as volumes for cut or ______.
The method of plotting the existing cross section is used for the purpose of obtaining quantities such as volumes for cut or ______.
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The procedure involves staking the centerline, then elevations are obtained at strategic points on the right angle to the ______.
The procedure involves staking the centerline, then elevations are obtained at strategic points on the right angle to the ______.
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A cross section design generally offers the expected level of service for ______.
A cross section design generally offers the expected level of service for ______.
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Super elevation is an important consideration in the geometric design for ______ and railways.
Super elevation is an important consideration in the geometric design for ______ and railways.
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The minimum sight distance available on a highway is called ______.
The minimum sight distance available on a highway is called ______.
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The height of the driver’s eye above the road surface is typically ______ meters.
The height of the driver’s eye above the road surface is typically ______ meters.
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In sight distance calculations, the height of the object above the road surface is generally ______ meters.
In sight distance calculations, the height of the object above the road surface is generally ______ meters.
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Factors that affect sight distance include the total reaction time of the driver and the ______ of the vehicle.
Factors that affect sight distance include the total reaction time of the driver and the ______ of the vehicle.
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The time taken from when an object is seen to when the brake is applied is known as the total ______ time.
The time taken from when an object is seen to when the brake is applied is known as the total ______ time.
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The two parts of total reaction time are perception time and brake ______ time.
The two parts of total reaction time are perception time and brake ______ time.
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The height of the driver’s eye is considered while measuring sight distance to prevent ______ with obstructions.
The height of the driver’s eye is considered while measuring sight distance to prevent ______ with obstructions.
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A slope of 2.5:1 refers to the side ______ of a roadway.
A slope of 2.5:1 refers to the side ______ of a roadway.
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The prismoidal formula for volume is given by 𝑽𝑷 = 𝟔 [𝑨𝟏 + 𝟒𝑨𝒎 + 𝑨𝟐], where 𝑨𝟏, 𝑨𝒎, and 𝑨𝟐 represent different areas and 𝑉 stands for ______.
The prismoidal formula for volume is given by 𝑽𝑷 = 𝟔 [𝑨𝟏 + 𝟒𝑨𝒎 + 𝑨𝟐], where 𝑨𝟏, 𝑨𝒎, and 𝑨𝟐 represent different areas and 𝑉 stands for ______.
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To find the volume with prismoidal correction, we use the formula 𝑽𝑪 = (𝑪𝟏 - 𝑪𝟐) (𝑫𝟏 - 𝑫𝟐) / ______.
To find the volume with prismoidal correction, we use the formula 𝑽𝑪 = (𝑪𝟏 - 𝑪𝟐) (𝑫𝟏 - 𝑫𝟐) / ______.
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In Example #1, the trench was found to be 4.8m wide and ______ deep at Station 5+420.
In Example #1, the trench was found to be 4.8m wide and ______ deep at Station 5+420.
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At Station 20+200, the left value is 6.60, the center value is 0, and the right value is ______.
At Station 20+200, the left value is 6.60, the center value is 0, and the right value is ______.
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In the example involving a cross-sectional area, the given area was 13.1625 m2 with a side slope of 1.5:1 and a road width of ______.
In the example involving a cross-sectional area, the given area was 13.1625 m2 with a side slope of 1.5:1 and a road width of ______.
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In the example #2, the area at station B was to be determined if the total area is ______.
In the example #2, the area at station B was to be determined if the total area is ______.
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The formula used for the END – AREA METHOD is 𝑽𝐸 = ______.
The formula used for the END – AREA METHOD is 𝑽𝐸 = ______.
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The rectangular trench example shows measurements at Sta. 5+420 and Sta. 5+450, highlighting a change in width from ______ to 5.20m.
The rectangular trench example shows measurements at Sta. 5+420 and Sta. 5+450, highlighting a change in width from ______ to 5.20m.
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The initial grade of the vertical curve is [-3.2%] and the final grade is ______.
The initial grade of the vertical curve is [-3.2%] and the final grade is ______.
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The height of the obstruction mentioned is ______ centimeters.
The height of the obstruction mentioned is ______ centimeters.
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The stopping sight distance required for the design is ______ meters.
The stopping sight distance required for the design is ______ meters.
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The average height of headlights of vehicles that will pass through the road is ______ centimeters.
The average height of headlights of vehicles that will pass through the road is ______ centimeters.
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The term for the minimum distance needed for a safe overtaking maneuver is ______ sight distance.
The term for the minimum distance needed for a safe overtaking maneuver is ______ sight distance.
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When overtaking, the vehicle occupies the ______ lane.
When overtaking, the vehicle occupies the ______ lane.
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The safest sight distance for entering an uncontrolled intersection is referred to as ______ sight distance.
The safest sight distance for entering an uncontrolled intersection is referred to as ______ sight distance.
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In rural areas, the guideline considers the ______ where the road is being constructed.
In rural areas, the guideline considers the ______ where the road is being constructed.
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The corner sight distance available in an intersection allows a driver to observe the actions of vehicles on the crossing ______.
The corner sight distance available in an intersection allows a driver to observe the actions of vehicles on the crossing ______.
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Evaluations involve establishing the needed sight ______ in each quadrant.
Evaluations involve establishing the needed sight ______ in each quadrant.
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A clear sight triangle must be free of sight ______ such as buildings, vehicles, and trees.
A clear sight triangle must be free of sight ______ such as buildings, vehicles, and trees.
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The coefficient of friction between the tires and the road is ______.
The coefficient of friction between the tires and the road is ______.
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To avoid a head-on collision, the minimum sight distance must be calculated based on the speeds of two cars approaching at ______ kph and 60 kph.
To avoid a head-on collision, the minimum sight distance must be calculated based on the speeds of two cars approaching at ______ kph and 60 kph.
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The minimum length of a crest vertical curve must provide a stopping sight distance of ______ m.
The minimum length of a crest vertical curve must provide a stopping sight distance of ______ m.
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Assume eye-height of ______ m and object height of 0.15 m for the calculations.
Assume eye-height of ______ m and object height of 0.15 m for the calculations.
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For a design speed of 80 kph, compute the minimum length of vertical curve that provides ______-m of stopping sight distance.
For a design speed of 80 kph, compute the minimum length of vertical curve that provides ______-m of stopping sight distance.
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The stopping sight distance may be expressed where v is in ______ and a is the braking action deceleration.
The stopping sight distance may be expressed where v is in ______ and a is the braking action deceleration.
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Braking action is based on the driver's ability to ______ the vehicle while maintaining control.
Braking action is based on the driver's ability to ______ the vehicle while maintaining control.
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A deceleration rate of ______ m/s² is comfortable for 90% of drivers.
A deceleration rate of ______ m/s² is comfortable for 90% of drivers.
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In the example provided, the vehicle is traveling at ______ kilometers per hour.
In the example provided, the vehicle is traveling at ______ kilometers per hour.
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If the coefficient of friction between the road and tires is ______, the driver's braking performance can be evaluated.
If the coefficient of friction between the road and tires is ______, the driver's braking performance can be evaluated.
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The driver steps on the brakes ______ seconds after seeing the obstruction.
The driver steps on the brakes ______ seconds after seeing the obstruction.
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The wall in the example is ______ meters high.
The wall in the example is ______ meters high.
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If SSD is greater than ______, the vehicle will not hit the wall.
If SSD is greater than ______, the vehicle will not hit the wall.
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Study Notes
Highway and Railroad Engineering: Lesson 4.2
- The lesson covers geometric design for highways and railways
- Topics include spiral curves, super elevation, earthwork, and sight distance
Geometric Design for Highway and Railways
- Variables for highway cross-section design include traffic volume, traffic characteristics, traffic speed, and characteristics of vehicles and drivers
- A wider pavement (7.20 meters) has fewer accidents compared to narrower pavements (less than 5.50 meters)
- A 7.20-meter wide pavement displayed 18% less accidents compared to narrower ones, and 4% fewer accidents compared to a 6.00 meter roadway
- Accident records show no difference between 6.60 meters and 7.20 meters wide pavements
- A wider pavement with 2.70-3.00 meter shoulder saw a 30% decrease in accidents whereas a pavement with 0-0.60 meter shoulder showed a 20% decrease in accidents when compared with a width of 0.90 to 1 .20 meter
Topics Outline
- Spiral curves
- Super elevation
- Earthwork
- Sight distance
Cross Section of Typical Highway - Earthwork
- The volume of traffic
- Character of the traffic
- Speed of the traffic
- Characteristics of motor vehicles and drivers
- A cross-section design generally offers the expected level of service for safety
- A recent study showed a 7.20-meter wide pavement has 18% fewer accidents than narrower pavements
Cross Section Method - Earthwork
- Plotting the existing cross-section perpendicular to a line for volume calculation
- Elevations are taken at strategic points on the right angle of centerline at full or half-station intervals
- Data is needed to estimate the amount of cut or fill needed for a roadway strip
Volume Approximation Methods in Earthwork
- End-area method: Ve = ½ [A1 + A2]
- Prismoidal formula: Vp = ⅓ L [A1 + 4Am + A2]
- Prismoidal correction: Vc = ⅓ (C1 - C2)(D1 - D2) /12 Example calculations are provided in the slides.
Sight Distance
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Distance a driver can see an object
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Depends on driver's vision and atmospheric conditions
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Factors affecting stopping sight distance (SSD): driver reaction time, speed of vehicle, efficiency of brakes, frictional resistance between road and tire, and road gradient
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Total reaction time is divided into perception time (object comes into sight to recognizing need to stop) and brake reaction time (time from realizing need to stop to pressing brake)
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Stopping sight distance calculations use PIEV theory (Perception, Intellection, Emotion, Volition)
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Analysis of SSD: the sum of lag distance (distance vehicle travels during reaction time) and braking distance.
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Lag distance = v * t
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-v = design speed, t = total reaction time
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Braking Distance = v^2 / 2gf
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- v = speed
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- g = gravitational acceleration (9.81 m/s^2)
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- f = coefficient of longitudinal friction
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Calculations for different scenarios are included.
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Types of sight distance:
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Stopping sight distance (SSD)
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Safe overtaking sight distance (OSD)
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Elements of OSD calculation process:
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Initial maneuver distance (d₁)
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Distance during passing (d₂)
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Clearance length (d₃)
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Distance opposing vehicle travels (d₄)
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Sight distance values are determined using AASHTO policy for highway and street design
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Terrain considerations for rural areas are also demonstrated
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Additional examples are provided in the slides.
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Description
This quiz explores the critical variables involved in highway cross-section design, including lane widths, shoulder dimensions, and accident records. It examines how these factors impact safety and traffic flow, emphasizing the importance of proper geometric design for highways and railways. Test your knowledge on the principles of highway engineering and safety metrics.
