highway engineering lecturer notes - chapter 1&2
DESCRIPTION
higway engineeringTRANSCRIPT
HIGHWAY ENGINEERING
ECG 304
Intan Shafika Saiful BahriFaculty of Civil Engineering
UiTMPP
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Course Outcomes1. Describe the process involved in the development and
construction of highways
2. Carry out simple traffic studies and apply the knowledge in highway geometric design and traffic control devices by using recommended standards and specification
3. Perform simple flexible pavement design according to JKR Arahan Teknik (Jalan) method and the selection of appropriate material for used in the construction.
4. Supervise road construction, identify road defect and recommends appropriate solution.
5. Perform the standard highway laboratory tests and data analysis.
Programme Outcomes1. Ability to acquire & apply basic knowledge of science,
mathematics & engineering.2. Ability to communicate effectively, not only with engineers
but also with the public.
3. Ability to identify, formulate & solve engineering problems.4. Ability to function on multi-disciplinary teams.5. Ability to act effectively as an individual and in a group,
with leadership, managerial & entrepreneurial capabilities6. Understanding the social, cultural, global & environmental
responsibilities & ethics of an engineering personnel & the need for sustainable development
7. Recognizing the need to undertake lifelong learning & possessing the capacity to do so.
Course Description
• Historical development of highways in Malaysia
• Traffic Engineering theory
• Road geometric design
• Traffic control devices
• Pavement design
• Road construction and maintenance
Chapter 1
Content:1. Development of highway tra
nsportation 2. Highway classification and
administration3. Feasibility studies and route
location4. Road safety and current
issues
Learning OutcomesAt the end of this chapter, students should be able to:
• Describe the process involved in the development and construction of roads and highway as general as well as in Malaysia.
• Describe the general aspects of highway classification and administration
• Explain the importance of feasibility studies and identify the route location consideration factors.
• Discuss on way to improve road safety and current issues (transportation challenges).
Development of highway transportation
• Transportation : Everything involved in moving either the person or goods from the origin to the destination.
Transportation
Mobility
Accessibility
Movements – different modes e.g walking, driving etc
Entry and exit
Why do we provide and develop road infrastructure?
• To expedite economy recovery development
• May benefit the surrounding areas - upgraded to reduce accidents, congestions
• Investment in mode and road infrastructure – to meet the demands and private transportation
Development of highway transportation (con’t)
History of road construction
•Roman Roads
•Metcalf’s Road (1717)
•Telford’s Road (1757)
•Mac Adam’s Road (1756)
Development of highway transportation (con’t)
Roman Roads
Paving Stones
Fine Concrete
Broken Stones
Rubble Stones
• Used by horses, chariot, wagon – pulled by animals
• Made-up from the stone blocks placed closed together
Development of highway transportation (con’t)
Metcalf’s Road
Gravel
Excavated Road Material
Large Stone Foundation
• Insisted on good drainage and foundation or subbase
• carriageway was arched – assist surface water drainage
• Crossing soft ground, he introduced a subbase raft of bundled heather
Development of highway transportation (con’t)
Telford’s Road
Gravel
Broken Stone
Hand Pitched Stone
• Improved ride ability - ‘sandwich’ smaller stones between the boulders
• smaller stones filled voids between the stone blocks – compacted until smooth surface obtained
Development of highway transportation (con’t)
Mac Adam’s Road
Camber
Gravel
• Several layers of compacted stones
• Foundation improvement – removing the topsoil
Development of highway transportation (con’t)
•Last decade before independent – tar road constructed in cities and town – Mac Adam
•Animal drawn carts to mechanical and motorized vehicles
Pre-Independent Era
•Before independent – walking or animal’s cart and few motorized car by means of footpath and bullock cart tracks
•Rubber plantation and tin mining increase demand for a better serviceability of road network – weak laterite
•Planning of road in Malaya – British Administration
Development of highway transportation (con’t)
•Now, Malaysia has one of the finest systems of road network system in the world
•Bituminous or concrete road – provide accessibility to residents (urban or rural)
•Expressway stretching from the north to the south of peninsular Malaysia (PLUS)
•Federal highway – links between states
Post-Independent Era
Development of highway transportation (con’t)
Post-Independent Era
Highway/Road Classification
•Roads are divided into two groups by area: -
Rural Urban
* Located outside of cities
* Serve as links between population centers
* Used for commuting & shopping trips
* Serve areas of high density land
Rural Road
• Expressway- divided highway for through traffic- full access control and grade separation at all intersection.- speed limit is 110 km/h
• Highway- link up directly/indirectly federal capitals, state capitals.- serve long to intermediate trip lengths- speed high to medium (not important as expressway)- smooth traffic with partial access control
• Primary road- major roads within a state- serve intermediate trip lengths & medium travelling speed- smooth traffic with partial access control- link up state capitals, district capitals and major towns
• Secondary road- major road within district- serve intermediate trip lengths with partial access control
• Minor road - apply to all road other than mentioned earlier- serve mainly local traffic, short trip lengths, no access control
Rural road (con’t)
Urban Road
• Expressway- as mentioned in rural road
• Arterial- continuous road with partial access for through traffic within urban area- Convey traffic from residential area to CBD- smooth traffic flows and carry large traffic volume
• Collector- Serve as collector or distributor between the arterial and local road system- partial access control- penetrate and serve identifiable neighbourhoods, commercial areas and industrial areas
• Local street- basic road networks within a neighbourhoods- serve direct access to abutting land- links to the collector road & short trip lengths- through traffic should be discouraged
Rural road (con’t)
Highway Administration
Federal State
•City Hall, Municipal or Local Council
• Kampung (District Office) Roads – depend on jurisdiction
•Under Federal Road Ordinance
•Linking State Capitals, airport, railway station and ports
•Road within the FELDA land scheme those with other regional land scheme constructed with Federal funds
• Constructed with state funds
Local Authority
Private
Traffic census
Class of Road
Capacity
Route Location
Environmental Impact
Assessment
Feasibility Study
Structures
Finalizing the Route
Route location
Consideration Factors:
Topography – terrain Soil condition Environment Economy/socioeconomic Politic History
Example: 7- Keep grades and curvature to
minimum
6- Avoid sudden changes in sight
distance, especially near junction
1- Avoid crossing
waterways 2- Flat area rather than
mountainous
3- Avoid destruction/removal man-made
culture
4- Avoid deep cuttings and expensive tunnel
5- Locate near to sources of
pavement material
8- Avoid ground of mining subsidence
9- Locate highway on soil that need least pavement
thickness above it
10- River crossing should be right angle
Route location (con’t)
Road Safety in Malaysia
How to improve?
Multimedia Road Safety Campaign
Ops STATIK and Ops SIKAP
Intro to Defensive Driving
Proposed Amendments To Road Safety Act 1987
Increase awareness and understanding of road safety
Improve heavier penalties on drivers – including mandatory jail
Driver’s offences recorded and summonses were given
Upgrading quality of instruction, instructors and training facilities at driving school
Safety helmet & safety clothing
Proposal for Dedicated Motorcycle
Lane
Proposal to Limit Max Speeds of
Motorcyclists
Road Safety in Malaysia (con’t)
How to improve?
Safety campaigns at state & district level
To reduce accidents and fatalities
Still under study by The Ministry of Transport
Be a policy decision for proposed new highway
Standard application to Malaysian Roads
Higher design speeds for roads those provide long distance travel
Lower design speeds for roads those serve local traffic, where the effect of speed is less significant
Higher standard for roads with heavier traffic
In Malaysia, design standards for roads are classified into 7 groups for urban & rural categories. The reason why road design standards in Malaysia need to be standardized particularly with their geometric design features are as follows:
To provide a uniformity in the design of roads based on the performance requirementsTo provide consistent, safe and reliable road facilities for traffic movementTo provide a guide for less subjective decisions on road design
Agencies Involved In Highway & Traffic
• JKR (The Public Works Department)- Implementation of development projects (federal road, state road, bridge & airport)- make sure all roads are in a good condition & safety
• JPJ (The Road Transport Department)- increase road safety through observation of motorized vehicles & drivers- implement the Road Transport Act 1987- Update the road tax system
• LLM (Malaysia Highway Authority)- plan, design, construct & maintain highway links &
facilities.- collect the toll & other payment which are related.
Benefits of Highway Privatization
• Reduce government financial burden
• Cost saving due innovation in const. techniques
• Users enjoy – improved standard of service & greater accessibility
• Earlier implementation and completion of highway project
• Create more job opportunity
Roadway Ideal Conditions
Lane width 3.6 m
Clearance 1.8 m
Free-flow speed of 100 km/h
No No Passing Zone on two-lane highway
No parking near the curb
Level terrain
No pedestrians
Only passenger cars in the traffic stream (no heavy vehicles)
Transportation System Challenges
• Transportation system exists to meet perceived social and economic needs.
• As the transportation system itself evolves, situations arise as a problem – serve as challenges to the transportation engineering profession.
• These challenges are1. Managing congestion – by demand or supply measures2. Improving safety – traffic accidents concern3. Providing equal access – poor, elderly, and physically
handicapped4. Protecting the environment – EIA 5. Incorporating new technology - ITS6. Securing financial resources - funding
Current Issue
•Serious urban traffic congestion
•Highway-related crashes- Over 40,000 traffic fatalities each year
•Delay
•Parking difficulties
•Pollution – noise and air (CO,NO, hydrocarbons)
Chapter 2
Content:1. Spot speed studies, design
speed, operating speed, running speed and speed limit
2. Traffic volume characteristics, flow rate, highway capacity and Level of service (LOS)
Learning Outcomes
At the end of the chapter, students should be able to:
1. Carry out simple speed studies and apply the knowledge in highway geometric design by using recommended standards and specification.
2. Carry out simple volume studies and apply the knowledge in traffic signal design by using recommended standards and specification.
Contents
• Traffic Stream Parameters Microscopic Macroscopic• Measurements Manual Inductive loops Speed guns• Traffic Stream Models Green shield's speed-density relationship Fundamental diagram
Traffic Studies
• Three (3) main categories:-
1. Inventories
A list or graphic display of existing information – street widths, parking spaces, transit routes, etc
2. Administrative
Existing engineering records, available in government agencies & departments
3. Dynamic
collection of data under operational conditions – speed, traffic volume, travel time & delay, parking and crashes.
Traffic measurements
Plan, improve road system
Distribution & performance of existing traffic
Traffic flow & speed
Traffic planning studies
Implemented with the help of 3-E’s (Engineering, Enforcement and Education)
Microscopic vs. Macroscopic Measures
• Microscopic measures: individual vehicle
1. Time headway: hi (sec/veh)
2. Space headway: si (ft/veh or km/veh)
3. Speed of individual vehicle: ui (mi/hr or km/hr)
• Macroscopic measures: average of n vehicles
1. Flow: q (veh/hr or vph)
2. Density: k (veh/mi or veh/km)
3. Speed: u (mi/hr or km/hr)q = uk
Spot Speed Studies
Study of speed of traffic at one point or spot on a traffic way
Aims – to determine the enforceable speed limits
To estimate the speed distribution of the traffic stream
110
km/j 80
km/j90
km/j30
km/j
60
km/j
Time of day & Duration
1. Establish posted speed limits2. Observe speed trends3. Collect basic data
4. Response to citizen complaints→ reflects the nature of complaints
Duration at least 1 hour and the sample size is at least 30 vehicles.
Traffic is free-flowing, usually off-peak hours
Where to make spot speed studies?
Free flow
Junction
High frequency of accident rate
Important locations for traffic operation
Representative location for basic data survey
Factors affecting spot speed studies
DriverVehicle
RoadwayTraffic
EnvironmentOR
OR
OR
Application of spot speed data
For trends in the operating speed
For speed at problem location
For traffic operation – speed limit & safe speed at curve
For geometric design features
For research studies
110
km/j
Methods of Measurement
Manually Automatically
200m
0 sec
Speed = distance/time
= 200m/8sec
V = 25m/s = 90kph
8 sec
Speed Studies
- Road detectors
- Radar speed meter
(commonly used)
Or Sonic detector
- Time laps camera
Manual
Observe the time required by a vehicle to cover short distance.
Direct timing procedure Two reference points are located at a
roadway, fixed distance apart. Observer starts and stops a stopwatch as
a vehicle enters & leaves the test section. It is most uncomplicated way. Disadvantages: Parallax effect
Road detectors
Classified into two general categories: a) Pneumatic road tubes
two tubes laid across the lane an impulse is recorded when the front
wheels pass over the first tube, second impulse is recorded when the front
wheels pass over the second tube. time elapsed between the two impulses
& distance between the tubes are used to compute the speed.
b) An inductive loop rectangular wire loop buried under the
roadway surface.
Advantages:
a) human errors are reduced
b) accurate results
Disadvantages:
a) devices rather expensive
b) affect driver behavior
c) wear & tear
Speed Meter
Two types:a) Radar speed meter
transmit signal onto a moving vehicle change in frequency between transmitted signal & reflected signal = speed. operating distance about 45 m
b) Sonic detector meter using ultrasonic tone (18-20 kHz) output in current voltage that is proportional to vehicle speed.
Advantages:
a) portable
b) reduced the influence on driver
behaviour.
Disadvantages:
a) difficult for two-lane road
b) expensive
Electronic-principle detectors Vehicles is detected through electronic
means. Traffic characteristics can be obtained –
speed, volume, queues & headways. Consists of an electronic camera &
microprocessor. Advantages: permanent visual will be
recorded
Speed
– Rate of movement of the vehicle, expressed in
miles/hour (mi/h) or kilometers/hour (km/h). Average spot speed /Arithmetic mean speed /
Time mean speed (*)
- Arithmetic mean of all observed vehicle
speeds. Total of spot speeds/No of vehicles. Overall travel time
- Time travel including stop and delays. Overall travel speed/journey speed (*)
- The speed over a specified section of
highway. Distance/overall travel time.
Definition:
Operating speed (*)- the highest overall speed a driver can travel
under a favorable weather condition w/out exceeds the speed limits
Running speed (*)- the average speed maintained over a
particular distance which the vehicle is in motion. Distance/ (Time travel – time delay)
Running delay- delay caused by interference between components of traffic (stream flow, parking)
Design speed- the speed determined for design as related to the physical features of a highway that might
influence vehicle operation.- the max safe speed that can be maintained over a specified section of highway when conditions
are so favorable.
Median speed
- speed at the middle value in a series of spot
speeds that are arranged in ascending order Modal speed
- speed value with highest frequency (observation) in a sample of spot speeds.
Pace/Mode
- the range of speed (5-10 km/h intervals) that has the greatest number of observations.
Standard deviation of speeds
- measure of the spread of the individual speeds. Space mean speed
- the arithmetic mean of speeds of vehicles occupying a relatively long section of street or highway at given instant.
Analysis and data presentation(refer Ex 4.2 pg 93)
• Table
Speed group
Mean speed, v
Frequency, f
fv % f Cumulative % f
f(v-u)2
10 – 14.9 12.5 0 0 0
• Histogram
fre
qu
ency
Speed, kph
• Frequency distribution
• Cumulative distribution
Time mean speed vs. space mean speed
Time mean speed
= Total speed No of vehicles
Space mean speed
= Total distance Total time
Six vehicles traveling through a section of a rural secondary road with the speeds measured at 68, 71, 79, 82, 76 and 74 km/h respectively. Assuming every vehicle was traveling at constant speed over the section of road, calculate the space mean speed and time mean speed.
Volume Studies
• collect data on the no of vehicles and/or pedestrians that pass a point on a highway facility during a specified time period.
• Time period – little as 15 min to as much as a year, depends on the use of the data.
• Data collected – put into subclasses.
Types of Traffic Daily Volume
Average Annual Daily Traffic (AADT)Average 24 hour volume over a year
Average Annual Weekday Traffic (AAWT)Average 24 hr volume occurring on weekdays
over a year Average Daily Traffic (ADT)
Same as AADT, but average over period less than a year, say, a month
Average Weekday Traffic (AWT)Same as AAWT, but average over period less
than a year, say, a month
Applications of AADT/ADT
• AADT Applications
1. Estimation of highway use
2. Estimation of trends
3. Economic feasibility evaluation
4. Planning
5. Maintenance
• ADT Applications
1. Planning of highway activities
2. Measurement of current demand
Peak Hour Volume (PHV)
• The max no of veh passing a point on a highway over 60 consecutive minutes
• Peak Hour Factor (PHF)
PHF = Peak hour volume
4 x The maximum15 minute volume
• Mainly used for urban:
1. Highway design (e.g. highway classification, no of lanes, signalization)
2. Traffic management (e.g. capacity analysis, parking)
Example: PHF
Determine
(a) the hourly volume,
(b) the peak rate of flow within the hour, and
(c) the peak hour factor
Time Period Volume
8:00 – 8:15 AM 150
8:15 – 8:30 AM 155
8:30 – 8:45 AM 165
8:45 – 9:00 AM 160
Volume Characteristics
Three basis of traffic flow:1. Hourly
The traffic flow mostly for a day – traffic volume varies from hour to hour.2. Daily
Distribution of traffic flow every day from Sunday to Saturday in a week.3. Monthly
Distribution of traffic flow for each month from January to December in a year
Refer figure 4.14 pg 110 in your textbook
Traffic Count
The duration can be 1 hour, 1 day or 1 yearUnit: no. of vehicle or passenger car unit
(PCU)Traffic can be divided into type & class of
vehicle – car, motorcycle, bus, lorry, etcPCU – standard unit of measurement
designed to give the effect of an equivalent numbers of passenger cars.
VehicleClassification
Equivalent Value in PCU’s
RuralRoads
UrbanRoads
Roundabout Traffic Signal/
Junction
Passenger CarsPedal CycleMotor CyclesLight VansMedium LorriesHeavy LorriesBuses
1.000.501.002.002.503.003.00
1.000.330.752.002.503.003.00
1.000.200.752.002.802.802.80
1.000.200.332.001.752.252.25
Table 2.1: Conversion factor from no of veh to PCU
Arahan Teknik (Jalan) 8/86, JKR
Methods of Conducting Volume Counts
Manual method
• Involves one or more persons recording observed vehicles using a counter.
• Advantages:a) not required specializedb) accurate results
• Disadvantages:a) labour intensive – can be expensiveb) cannot be use for long periods of counting
Automatic Method
• Laying of surface detectors (pneumatic road tubes) or subsurface detectors (magnetic or electric contact devices) on the road.
• Detect the passing vehicle & transmit the information to a recorder.
• Advantages;a) not required specializedb) accurate results
• Disadvantages;a) wear & tearb) disrupts traffic during installation
Types of Volume Counts
• Cordon Counts* conduct at central business district (CBD).* imaginary closed loop as cordon area.* intersection crossing the cordon line – count station.* Volume counts of vehicles enter & leaving
cordon area are taken.* data used: planning parking facilities, updating & evaluating traffic operational technique.
• Screen Line Counts* study area are divided into large sections
by running imaginary lines (screen lines) across it.
* traffic counts are taken at each point where a road crosses the screen line.
• Intersection Counts* determine vehicle classifications through
movements & turning movements at intersections.* determine phase lengths & cycle time for
signalized intersection, design of channelization.
Analysis of Traffic Volume Data
Hourly Volume Characteristics
Flo
w (
pcu
/h/l
)
Time (a.m-p.m) 7.00 8.00 9.00 10.00 11.00 12.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00
WeekdayWeekend
Daily Volume Characteristics
Veh
icle
per
day
Day per week
Sunday Monday Tuesday Wednesday Thursday Friday Saturday
Zone AZone B
Flo
w (
pcu
/h/l
)
Year
1998 1999 2000 2001 2002 2003 2004 2005
Annually Volume Characteristics
- Increment of traffic volume
Definition
Design VolumeThe volume of traffic estimated to use the road during the design life.
Design VehicleA selected motor vehicle which the weight, dimensions & operating characteristics are used to establish highway design controls to accommodate vehicles of a designated type.
Service volumeMax volume of traffic that a designed roadway would be able to serve without undue congestion falling below prescribed level of service (LOS) at the time the traffic is at design hourly volume.
Highway capacityAbility to accommodate traffic & usually expressed as no of vehicles that can pass a given point in a certain period of time at a given speed.
Level of service (LOS)Term used to classify the varying conditions of traffic flow that take place on highway. The various level of service range from the highest level (flow where drivers are able to travel at their desired speed with freedom to manoeuvre) to the lowest level (obtained during congested stop-start conditions).
Level of service (LOS)
The LOS of existing highway may be evaluated by comparing measured traffic volume to the capacity of that facilities.
Each road has its own capacity depending on a) speedb) travel timec) safetyd) traffic interruption
LOS = volume/capacity
Relationship of LOS to operating speed and Flow
A
B
C
D
E
F
Sp
eed
Flow
Free Flow
Stable Flow
Approaching Unstable Flow
Unstable Flow
Forced Flow