highway engineering lecturer notes - Chapter 1&2

HIGHWAY ENGINEERING

ECG 304

Intan Shafika Saiful Bahri

Faculty of Civil Engineering

UiTMPP

1

2

3

4

5

6

Course Outcomes

1. 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 Outcomes

1. 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 capabilities 6. 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

Chapter 1

Content:

1.

Development of highway

transportation

2.

Highway classification

and

administration

3.

Feasibility studies

and

route location

4.

Road safety

and

current issues

Learning Outcomes

At 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

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

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

History of road construction

•

Roman Roads

•

Metcalf’s Road

(1717)

•

Telford’s Road

(1757)

•

Mac Adam’s Road

(1756)

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

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

Mac Adam’s Road

Camber

Gravel

•

Several layers of compacted stones

•

Foundation improvement – removing the topsoil

•

Last decade before

independent – tar road

constructed in cities

and town – Mac Adam

•

Animal drawn carts to

mechanical and

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

•

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

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

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

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

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

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 requirements To provide consistent, safe and reliable road facilities for traffic movement

To 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.

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

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 are

1. Managing congestion – by demand or supply measures 2. Improving safety – traffic accidents concern

3. Providing equal access – poor, elderly, and physically handicapped

4. Protecting the environment – EIA 5. Incorporating new technology - ITS 6. Securing financial resources - funding

Current Issue

•

Serious urban traffic congestion

•

Highway-related crashes

- Over 40,000 traffic fatalities each year

•

Delay

•

Parking difficulties

•

Pollution

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

Contents

•

Traffic Stream Parameters



Microscopic



Macroscopic

•

Measurements



Manual



Inductive loops



Speed guns

•

Traffic Stream Models



Green shield's speed-density relationship

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,

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

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)

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/j

90

km/j

30

km/j

60

km/j

Time of day & Duration

1. Establish posted speed limits

2. Observe speed trends

3. 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

Factors affecting spot speed studies

Driver Vehicle Roadway Traffic Environment OR 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

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.

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

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.

 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

fr eq u en cy 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.

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

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

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

Traffic Count

The duration can be 1 hour, 1 day or 1 year

Unit: no. of vehicle or passenger car unit (PCU)

Traffic can be divided into type & class of vehicle – car, motorcycle, bus, lorry, etc

PCU – standard unit of measurement designed to give the effect of an

Vehicle

Classification

Equivalent Value in PCU’s

Rural Roads Urban Roads Roundabout Traffic Signal/ Junction Passenger Cars Pedal Cycle Motor Cycles Light Vans Medium Lorries Heavy Lorries Buses 1.00 0.50 1.00 2.00 2.50 3.00 3.00 1.00 0.33 0.75 2.00 2.50 3.00 3.00 1.00 0.20 0.75 2.00 2.80 2.80 2.80 1.00 0.20 0.33 2.00 1.75 2.25 2.25

Table 2.1: Conversion factor from no of veh to PCU

Methods of Conducting Volume Counts

Manual method

•

Involves one or more persons recording observed vehicles using a counter.

•

Advantages:

a) not required specialized b) accurate results

•

Disadvantages:

a) labour intensive – can be expensive

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 specialized b) accurate results

•

Disadvantages; a) wear & tear

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

Analysis of Traffic Volume Data

Hourly Volume Characteristics

Fl o 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 Weekday Weekend

Daily Volume Characteristics

V

ehicle

per day

Day per week

Sunday Monday Tuesday Wednesday Thursday Friday Saturday Zone A

Fl o w (pcu/ h/ l) Year 1998 1999 2000 2001 2002 2003 2004 2005

Annually Volume Characteristics

- Increment of traffic

Definition

 Design Volume

The volume of traffic estimated to use the road during the design life.

 Design Vehicle

A selected motor vehicle which the weight, dimensions & operating characteristics are used to establish highway design controls to accommodate vehicles of a designated type.

 Service volume

Max 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 capacity

Ability 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

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) speed b) travel time c) safety d) traffic interruption  LOS = volume/capacity

Relationship of LOS to operating speed and Flow A B C D E F Spe e d Flow Free Flow Stable Flow

Approaching Unstable Flow

Unstable Flow