Lesson 4: Geometric Design

Question 1

7 Divisions of Highway Design

Answer 1

1. Geometric Design
2. Intersection Design
3. Highway Drainage Design
4. Pavement Design
5. Earthworks
6. Road facilities
7. Roadway lighting

Question 2

The ___________________ of highway is one of the divisions of highway design concerned with the positioning of the physical elements of the roadway according to standards and constraints

Answer 2

geometric design

Question 3

3 main types of Geometric Design

Answer 3

1. Alignment
2. Grade line
3. Cross Section

Question 4

________________ (Horizontal –Plan) - is the route of the road, defined as a series of horizontal tangents and curves.

Answer 4

Alignment

Question 5

____________ (Vertical -Profile) - is the vertical aspect of the road, including crest and sag curves, and the straight grade lines connecting them.

Answer 5

Grade line

Question 6

_______________ - shows the position and number of vehicle and bicycle lanes and sidewalks, along with their cross slope or banking. Cross sections also show drainage features, pavement structure and other items outside the category of geometric design.

Answer 6

Cross section

Question 7

7 Geometric Design Elements

Answer 7

1. Design parameters
2. Sight distance
3. Horizontal Alignment
4. Vertical Alignment
5. Combination of Horizontal and Vertical Alignment
6. Cross Section
7. Drainage

Question 8

Design Speed

Design speeds ranging from _____ to _____ kph for local streets, and _____ kph or higher for collector streets

Answer 8

30, 50, 50

Question 9

Design Speed

Rural arterials other than expressways should be designed for speeds of _____ to _____ kph, depending on terrain, driver expectancy

Answer 9

60, 120

Question 10

Design Speed

Urban arterials should be designed for speeds of _____ to _____ kph

Answer 10

50, 100

Question 11

Design Speed

Expressways should be designed for speeds not less than _____ kph.

Answer 11

80

Question 12

Design Speed Implications

At _______ running speeds a rider or driver has ____ time to react to a situation and therefore there is the likelihood that an error will result in a crash

Answer 12

higher, less

Question 13

Design Speed Implications

____________ and _____________ of a vehicle increases rapidly with speed

*The sudden dissipation of this energy in a crash means that the injury to occupants is _______ severe

Answer 13

Momentum, kinetic energy, more

Question 14

The distance at which a driver of a vehicle can see an object ahead of time.

Answer 14

Sight Distance

Question 15

(adequate or inadequate) sight distances should be available along the full length of a road for vehicles to be able to stop (or overtake) safely.

Answer 15

Adequate

Question 16

Criteria for Measuring Sight Distance

Based from AASHTO Greenbook:

Height of Driver’s Eye
* ______ m = (for passenger cars)
* ______ m = (for large trucks)

Answer 16

1.08, 2.33

Question 17

Criteria for Measuring Sight Distance

Based from AASHTO Greenbook:

Height of Object
* ____ m = (for stopping)
* ____ m = (for passing)

Answer 17

0.60, 1.08

Question 18

Criteria for Measuring Sight Distance

Based from DGCS Volume 4 (3.6.1.5):

Height of Driver’s Eye
* _____ m = (in all cases)

Height of Object
* _____ m = (for stopping)
* _____ m = (for passing)

Answer 18

1.15, 0.15, 1.40

Question 19

3 Types of Sight Distance

Answer 19

1. Stopping (Non-Passing) Sight Distance
   2.Decision Sight Distance
   3.Passing Sight Distance

Question 20

Sight Distance

*Available distance on a roadway to enable a vehicle traveling at the design speed to stop before reaching a stationary object

*applied where only one obstacle must be seen in the roadway and dealt with.

Answer 20

Stopping Sight Distance

Question 21

Sight Distance

*Distance required for a driver to initiate and complete safely and efficiently the maneuver of an unexpected or otherwise difficult-to perceive information source or hazard.

*applied where numerous objects, pedestrians, vehicles or design features, complex control or complex surrounding land use, and topographic conditions must be addressed by the driver.

*It is substantially greater than the stopping sight distance.

Answer 21

Decision Sight Distance

Question 22

Sight Distance

*The sight distance long enough to enable a vehicle to overtake and pass another vehicle on a two lane highway without interference from opposing traffic.

*Distance required for a driver to see a sufficient object to complete the passing maneuver without cutting off the passed vehicle in advance of meeting an opposing vehicle appearing during maneuver.

Answer 22

Passing Sight Distance