Date post: | 04-Jun-2018 |
Category: |
Documents |
Upload: | maysara-maawia-mukhtar |
View: | 222 times |
Download: | 0 times |
8/13/2019 Chapter 1 Lecture1 Kcs3233
http://slidepdf.com/reader/full/chapter-1-lecture1-kcs3233 1/40
1
TRANSPORTATION ENGINEERING
KCS 3233/KAS 4172
Prepared by : Madam Syarifah Anom Ibrahim
8/13/2019 Chapter 1 Lecture1 Kcs3233
http://slidepdf.com/reader/full/chapter-1-lecture1-kcs3233 2/40
2
CHAPTER 1 – Lec ture 1
CHARACTERISTICS OF THE
DRIVER, PEDESTRIAN,VEHICLE AND THE ROAD
8/13/2019 Chapter 1 Lecture1 Kcs3233
http://slidepdf.com/reader/full/chapter-1-lecture1-kcs3233 3/40
3
1.1 DRIVER CHARACTERISTICS
14% of driver population comprise of 65 years old andabove
However, the ability to hear and see decreasing after65years old.
Human response process is the action taken by thedrivers on a road, result from evaluation and reactionobtained from stimuli that they see or hear.
However, it must be carried out in a very short time.
Therefore, it is important to the highway & transportationengineer to have some fundamental knowledge of visualand hearing perception
8/13/2019 Chapter 1 Lecture1 Kcs3233
http://slidepdf.com/reader/full/chapter-1-lecture1-kcs3233 4/40
4
8/13/2019 Chapter 1 Lecture1 Kcs3233
http://slidepdf.com/reader/full/chapter-1-lecture1-kcs3233 5/40
5
5 types of visual perception
1. Visual acuity
2. Peripheral vision
3. Colour vision
4. Glare and recovery
5. Depth perception
8/13/2019 Chapter 1 Lecture1 Kcs3233
http://slidepdf.com/reader/full/chapter-1-lecture1-kcs3233 6/40
6
1. Visual acuity
Visual acuity is the ability to see finedetails of an object.
Two types of visual acuity; static &
dynamic visual acuity.Factors that affect static acuity;
background brightness, contrast and time.
Most drivers have clear vision within the
conical angle 3-5 degrees, 10-12 degreesfairly clear, beyond this angle, usuallyblurred.
8/13/2019 Chapter 1 Lecture1 Kcs3233
http://slidepdf.com/reader/full/chapter-1-lecture1-kcs3233 7/40
7
2. Peripheral vision
Peripheral vision is the ability to see
objects beyond the cone of clearest vision.
Although objects can be seen within this
zone, but it not clear in details and colour.
Factors affected; speed of vehicle & age of
the driver
8/13/2019 Chapter 1 Lecture1 Kcs3233
http://slidepdf.com/reader/full/chapter-1-lecture1-kcs3233 8/40
8
3. Colour vision
The ability to differentiate one colour from
another.
Deficiency of this ability is considered
colour blindness
8/13/2019 Chapter 1 Lecture1 Kcs3233
http://slidepdf.com/reader/full/chapter-1-lecture1-kcs3233 9/40
9
4. Glare vision & Recovery
There are 2 types of glare vision; direct & speculars.
Direct glare vision – occurs when relatively bright lightappears in the individual’s field of vision
Speculars glare vision – when image reflected by therelatively bright light appear in the field of vision
Both conditions can cause discomfort to the eyes.
From dark-bright ; 3 seconds glare recovery
From bright-dark; > 6 seconds glare recovery
By age of 40, people are more sensitive to the glare.
8/13/2019 Chapter 1 Lecture1 Kcs3233
http://slidepdf.com/reader/full/chapter-1-lecture1-kcs3233 10/40
10
5. Depth perception
The ability of a person to estimate speed anddistance.
It is importance on 2-lane highways duringpassing maneuvers
This is due to the ability of human eye todifferentiate between objects
However, human eye is not very good to
estimate absolute speeds, distance, size andaccelerations.
That is why traffic control device are standardin size, shape and colour
8/13/2019 Chapter 1 Lecture1 Kcs3233
http://slidepdf.com/reader/full/chapter-1-lecture1-kcs3233 11/40
8/13/2019 Chapter 1 Lecture1 Kcs3233
http://slidepdf.com/reader/full/chapter-1-lecture1-kcs3233 12/40
12
Perception – reaction process
1. Perception = the driver sees the control device, warning
sign or object on the road
2. Identification = the driver identifies the objects andunderstand the stimulus.
3. Emotion = the driver decide what action to take
4. Reaction = the driver executes the action decided during
the emotion sub-process
8/13/2019 Chapter 1 Lecture1 Kcs3233
http://slidepdf.com/reader/full/chapter-1-lecture1-kcs3233 13/40
13
According to AASHTOO, recommended time for the perception-
reaction time is 2.5 seconds.
JKR suggested 3 seconds
EXAMPLE 1:
A driver with perception reaction time of 2.5 sec is driving at 65km/h when
he observes that an accident has blocked the road ahead.
Determine the distance that the vehicle will move before the driver couldactivate the brakes. The vehicle will continue to move at 65km/h during the
perception reaction time of 2.5 sec.
SOLUTION:
8/13/2019 Chapter 1 Lecture1 Kcs3233
http://slidepdf.com/reader/full/chapter-1-lecture1-kcs3233 14/40
14
1.2 Vehicle characteristics
Geometric design criteria of the road is partly based on the
; static, dynamic & kinematics characteristics of the
vehicle.
Static; include weight & size of vehicle
Dynamic; forces that causes the motion of vehicle
Kinematics; motion of vehicle without considering the
forces
8/13/2019 Chapter 1 Lecture1 Kcs3233
http://slidepdf.com/reader/full/chapter-1-lecture1-kcs3233 15/40
15
Conversions
1m = 3.28 ft
1 ft = 0.3 meter
1 mile = 1609.3 meter
1 meter = 0.000621371 mile
1 pound/lb = 0.45kilogram
1 kilogram = 2.2 pound/lb
8/13/2019 Chapter 1 Lecture1 Kcs3233
http://slidepdf.com/reader/full/chapter-1-lecture1-kcs3233 16/40
16
1.2.1. Static Characteristics
The size the design vehicle for a highway is an important
factor the determination of design standards for physical
components of the highway
These include; lane width, shoulder width parking bays
and length of vertical curves.
Table 3.1 shows the limit of static characteristics
8/13/2019 Chapter 1 Lecture1 Kcs3233
http://slidepdf.com/reader/full/chapter-1-lecture1-kcs3233 17/40
17
8/13/2019 Chapter 1 Lecture1 Kcs3233
http://slidepdf.com/reader/full/chapter-1-lecture1-kcs3233 18/40
18
Table 3.2 : Dimension of Design Vehicle
8/13/2019 Chapter 1 Lecture1 Kcs3233
http://slidepdf.com/reader/full/chapter-1-lecture1-kcs3233 19/40
19
8/13/2019 Chapter 1 Lecture1 Kcs3233
http://slidepdf.com/reader/full/chapter-1-lecture1-kcs3233 20/40
20
8/13/2019 Chapter 1 Lecture1 Kcs3233
http://slidepdf.com/reader/full/chapter-1-lecture1-kcs3233 21/40
21
8/13/2019 Chapter 1 Lecture1 Kcs3233
http://slidepdf.com/reader/full/chapter-1-lecture1-kcs3233 22/40
22
8/13/2019 Chapter 1 Lecture1 Kcs3233
http://slidepdf.com/reader/full/chapter-1-lecture1-kcs3233 23/40
23
1.2.2 Kinematics characteristics
• The important element among kinematics characteristicsis the acceleration capability of the vehicle.
• For a standing start to a speed of 25km/h, typical
maximum accelerations are; – For tractor-semi trailer truck = 0.9m/s²
– For large car = 4.5m/s²
For a speed change 0 to 48 km/hr, typical maximum accelerations
are;- For tractor-semi trailer truck = 0.5m/s²
– For large car = 3.1m/s²
– For high-performance sport car = 4.3m/s²
8/13/2019 Chapter 1 Lecture1 Kcs3233
http://slidepdf.com/reader/full/chapter-1-lecture1-kcs3233 24/40
24
1.2.3 Dynamic characteristic
• Several forces act on a vehicle while it in
motion;
1. Air resistance
2. Grade resistance
3. Rolling resistance
4. Curve resistance
8/13/2019 Chapter 1 Lecture1 Kcs3233
http://slidepdf.com/reader/full/chapter-1-lecture1-kcs3233 25/40
25
8/13/2019 Chapter 1 Lecture1 Kcs3233
http://slidepdf.com/reader/full/chapter-1-lecture1-kcs3233 26/40
26
1. Air resistance (R a)
Ra = air resistance (kg)
p = air density (1.227kg/m³)
CD = aerodynamic drag coefficient; 0.4(car), 0.5-0.8(trucks),0.5 typical v A = front cross sectional area (m²)
u = vehicle speed (km/h)
g = gravity (9.81)
g
Au pC R D
a
277.0
5.0
8/13/2019 Chapter 1 Lecture1 Kcs3233
http://slidepdf.com/reader/full/chapter-1-lecture1-kcs3233 27/40
27
2.Grade resistance
• m= vehicle mass (kg.s²/m)
• w = vehicle weight (kg)
• g = gravity (9.81)
• ⍬ = incline angle (°)
• G = gradient (%)
sinmg RG 100
wG RG
8/13/2019 Chapter 1 Lecture1 Kcs3233
http://slidepdf.com/reader/full/chapter-1-lecture1-kcs3233 28/40
28
3. Rolling resistance (Rr )
• R = rolling resistance force (kg)
• Crs = constant (0.012 for passenger car)
• Crv = constant (7 x 10-6 s2/m2)
• u = vehicle speed (km/h)
• W = gross vehicle weight (kg)
W uC C R rvrsr
2077.0
8/13/2019 Chapter 1 Lecture1 Kcs3233
http://slidepdf.com/reader/full/chapter-1-lecture1-kcs3233 29/40
29
4. Curve resistance
• Rc = curve resistance (kg)
• u = vehicle speed (km/h)
• W = gross vehicle weight (kg)
• g = acceleration (9.81)• R = radius curvature (m)
gR
W u Rc
2077.0
5.0
8/13/2019 Chapter 1 Lecture1 Kcs3233
http://slidepdf.com/reader/full/chapter-1-lecture1-kcs3233 30/40
30
Power requirements
• P = horsepower delivered (hp)(1 hp = 0.75 kw)
• R = sum of resistance to motion (N)
• u = speed of vehicle (km/h)
• v = vehicle velocity (m/s)
Rv P 76
278.0 Ru P
8/13/2019 Chapter 1 Lecture1 Kcs3233
http://slidepdf.com/reader/full/chapter-1-lecture1-kcs3233 31/40
31
Example 2
Determine the horsepower produced by a passenger car traveling at a
speed of 105 km/h on a straight road of 5% grade with a smooth pavement.
Assume the weight of car is 1800kg and the cross-sectional area of the car
is 3.8m² (pg 77)
8/13/2019 Chapter 1 Lecture1 Kcs3233
http://slidepdf.com/reader/full/chapter-1-lecture1-kcs3233 32/40
32
1.3 Road characteristics
• The road characteristics is related to
stopping and passing sight distance
because more related to the sub topic as
discussed before.
• Sight distance
• Sight distance is a length of highway
visibility ahead to the driver of a vehicle.
There are 2 sight distance situation
considered in the design.
8/13/2019 Chapter 1 Lecture1 Kcs3233
http://slidepdf.com/reader/full/chapter-1-lecture1-kcs3233 33/40
33
1.3.1 Stopping sight distance
• SSD for design purpose, is usually taken as the minimum sight
distance required for the driver to stop the vehicle after seeing an
object in the vehicle’s path without hitting the object.
G g
au
ut SSD
254
278.02
8/13/2019 Chapter 1 Lecture1 Kcs3233
http://slidepdf.com/reader/full/chapter-1-lecture1-kcs3233 34/40
34
8/13/2019 Chapter 1 Lecture1 Kcs3233
http://slidepdf.com/reader/full/chapter-1-lecture1-kcs3233 35/40
35
8/13/2019 Chapter 1 Lecture1 Kcs3233
http://slidepdf.com/reader/full/chapter-1-lecture1-kcs3233 36/40
36
8/13/2019 Chapter 1 Lecture1 Kcs3233
http://slidepdf.com/reader/full/chapter-1-lecture1-kcs3233 37/40
37
Example 3
• A temporary diversion has been constructed on a highway of +4%
gradient due to major repairs that are being undertaken on a bridge.
The maximum speed allowed on the diversion is 10mi/h(10km/h).
Determine the minimum stopping sight distance on the highway.
• Take a/g = 0.35
• Perception reaction time = 2.5s
8/13/2019 Chapter 1 Lecture1 Kcs3233
http://slidepdf.com/reader/full/chapter-1-lecture1-kcs3233 38/40
38
1.3.2 Passing sight distance
• The passing sight distance is the minimum
sight distance on a 2-lane, 2-way highway that
will permit a driver to complete a passing
maneuver without colliding with opposingvehicle & without cutting off the passed vehicle
4321 d d d d PSD
8/13/2019 Chapter 1 Lecture1 Kcs3233
http://slidepdf.com/reader/full/chapter-1-lecture1-kcs3233 39/40
39
8/13/2019 Chapter 1 Lecture1 Kcs3233
http://slidepdf.com/reader/full/chapter-1-lecture1-kcs3233 40/40
40