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R O A D A N D B R I D G E W

O R K S

THE REPUBLIC OF UGANDA

MINISTRY OF WORKS, HOUSING ANDCOMMUNICATIONS

ROAD DESIGN MANUAL

Vol. 1:Geoe!"#$ De%#&'

()l* 2++



FOREWORD

The Ministry of Works, Housing and Communications (MoWHC) Mission is to

promote an adequate, safe and well maintained transport infrastructure, anefficient and effective communication system, safe housing and uildings soas to effectively contriute to the socio!economic development of the country

"n e#ercising this mission and in discharging its responsiilities, the Ministry isissuing a series of $esign Manuals, %uidelines, Codes and &tandards, of which the 'oad $esign Manual ol* + %eometric $esign Manual- is one partthereof**

The purpose of this manual is to serve as a nationally recogni.ed document,the application of which is deemed to serve as a standard reference and

ready source of good practice for the geometric design of roads, and willassist in a cost effective operation and an environmentally sustainaledevelopment of the country/s road network*

The ma0or enefits to e gained in applying this document are theharmoni.ation of professional practice and the ensuring of appropriate levelsof safety, health and economy with due consideration of the o0ectiveconditions and need of the country*

This manual is a technical document, which, y its very nature, requiresperiodic updating from time to time arising from the dynamic technologicaldevelopment and changes* The Ministry, therefore, welcomes comments andsuggestions from any concerned odies, groups or individuals, as feedackon all aspects of the document during the course of its implementation* 1llfeed acks received will e carefully reviewed y professional e#perts with aview to possile incorporation of amendments in future editions*

John NasasiraMinister

Ministry of Works, Housing

and Communications2!



"eometric Design Manua# $ection %

$EC&'ON %

&()*E OF CON&EN&$

$EC&'ON %+ "ENER(* %%

+*+ "ntroduction*****************************************************************************************************%+

+*+*+ %eneral************************************************************************************************ %++*+*2 3urpose************************************************************************************************%+

+*+*4 &cope***************************************************************************************************%+

+*+*5 6rgani.ation of the Manual******************************************************************%2

+*2* 7nits of Measurement and 8anguage*************************************************************%2

+*4* $ocument 3reparation************************************************************************************%4

+*5 $epartures from &tandards*****************************************************************************%5

+*9 $efinitions and 1reviations**************************************************************************%5

&ERM'NO*O"'E$****************************************************************************************%29

*'$& OF &()*E$

Tale +!+ $efinitions of 3refi#es***************************************************************************%4

Tale +!2 :asic units, multiples and su!multiples***********************************************%4

Ministry of Works, Housing and Communications




$EC&'ON %+ "ENER(*

%% 'N&ROD-C&'ON

%%% "enera#

The %eometric $esign Manual sets forth the policy and standards to e adopted for thedesign of rural roads in 7ganda* %eometric $esign is an essential component in thedesign development of roads* This %eometric $esign Manual is one part of the revisedand developed version of the oad $esign Manual, ;ovemer +<<5* The revised anddeveloped oad $esign Manual is prepared in four parts*

3art " %eometric $esign Manual

3art "" Hydrology and Hydraulics $esign

3art """ 3avement $esign Manual

3art " :ridge $esign Manual

This oad $esign Manual supersedes the oad $esign Manual of ;ovemer +<<5 andit is intended for use in the design of all rural roads in 7ganda*

%%2 .ur/ose

The purpose of this design manual is to give guidance and recommendations to theengineers responsile for the geometric design of rural roads in 7ganda*

%%0 $co/e

The procedures for the geometric design of roads presented in this manual are

applicale to all classified roads as defined in this %eometric $esign Manual*

The contents of the manual are partly guidelines and recommendations to econsidered, and partly standards which as a general rule should e adhered to* "nsome instances special conditions may demand modifications to these standards, inwhich case special consideration should e given in consultation with the =ngineer!"n!Chief*

The use of the procedures descried in this manual should help in achievingreasonale uniformity in geometric design for a given set of conditions* "t is designed toassist the road design engineer in 7ganda and it is hoped that the road design engineer will contriute y putting forward any proposals for further development and revisionstemming from the actual field e#perience and practice and also which he considers will

result in a etter and more economical design*

%+





%%1 Organiation of the Manua#

The manual is divided into +2 sections as follows

&ection + is dealing with general such as introduction, units of measurement, definitionand areviations*

&ection 2 deals with preliminary design considerations* &pecifically, it lists procedures

for identification of potential alignments in the route corridor selection process*

&ection 4 is dedicated to survey requirements*

&ection 5 is the road system, which discusses on the road categori.ation andclassification in 7ganda* "t deals with division of roads into classes and design classesand also gives summary of geometric design parameters for the different designclasses of road*

&ection 9 is dealing with design controls and criteria affecting the selection of thegeometric design values* These include design vehicles, driver performance, trafficcharacteristics, capacity and level of service*

&ection > is elements of design, which deals with the various sight distances, hori.ontalalignment and vertical alignment*

&ection ? is dealing with cross section elements, which discusses mainly on lanewidths, shoulders, medians, clear .ones, right of way, side and ack slopes and givestypical cross sections of the different design classes of roads*

&ection @ discusses at!grade 0unctions, including design requirements, selection of 0unction type, t!0unctions, cross 0unctions and roundaoutsA sight distancesA and 0unctionelements including turning lanes and traffic islands*

&ection < is "nterchanges or grade!separated 0unctions

&ection +B is &peed Management, &ection ++ is 6ther oad acilities and &ection +2 isoad urniture, oad Marking and Miscellaneous items*

%2 -N'&$ OF ME($-REMEN& (ND *(N"-("E

The language of the manual is =nglish*

The standard units of measurement to e used are ased on the "nternational system(&") units* However, the units applicale to road design also include some units whichare not strictly part of &"*

Multiples and su!multiples of &" units are formed either y the use of indices or

prefi#es* $efinitions of applicale prefi#es are given elow*

The asic units and the derived and supplementary units which will normally erequired for road design are +isted in the tale elow*

%2





&a3#e %4%+ Definitions of .refi5es

.refi5 $ym3o#Factor 3y 6hich the unit

is mu#ti/#ied

mega

kilo

hecto

deca

deci

centi

milli

Micro

M

D

H

da

d

c

m

µ

+B>

+B4

+B2

+B

+B!+

+B!2

+B!4

+B!>

&a3#e %42+ )asic units, mu#ti/#es and su34mu#ti/#es

'tem -nit $ym3o#Recommended Mu#ti/#es and su34

mu#ti/#es

8ength Meter m km, mm

Mass Dilogram kg Mg, g, mg

Time &econd s $ay (d), hour (h), minute (min)

1rea &quare meter m2 km2, hectare (+ha E +B,BBBm2), mm2

olume (solids) Cuic meter m4 cm2, mm4

olume (liquid) 8itre l ml (+mlE+B!4 l, +mlE+cm4)

$ensity Dilogram per cuic meter kgFm4 +MgFm4E+kgF+B4l, gFml

orce ;ewton ; M;, k; (+;E+ kgmFs2, +kgfE<*@+;)

3ressure and&tress

;ewton per square meter ;Fm2 k;Fm2, ;Fmm2

elocity (&peed) Meter per second mFs kmFh (+ kmFhE+F4*>(mFs)) 1ngle $egree or grade 6

gMinute (G), second ('-) (4>Bo circle)(5BBg circle)

Temperature $egree Celsius oC

%0 DOC-MEN& .RE.(R(&'ON

ecommended $rawing &cales

The following scales are recommended when preparing detailed design drawings, plansand charts*

8ocation Map (whole of 7ganda) + in +,BBB,BBB

8ocation 3lan ariale + in +,9BB,BBB

+ in +,BBB,BBB

+ in 2BB,BBB

Dey 3lan %enerally + in 9B,BBB

3lan and 8ongitudinal profile

&ection 3lan + in 2,BBB

8ongitudinal &ection Hori.ontal + in 2,BBB

ertical + in 2BBCross!&ections

%4





"ndividual cross!sections + in 2BB F +F5BB

Typical Cross &ection + in 9B (natural)

3avement $etail (&how half cross section) + in 29 (natural)$etails of unctions and 8ay :yes + in 29BF9BF+B

+ in 9BBF+BB

$etails of encing and %ates + in 2B

$rainage $etails + in 2BBF+BBF9BF2BF+BF9

%uardrail $etails + in +BBF29F+B

Culverts + in 2BBF+BBF9BF29

:orrow 3it Dey 3lan + in 9B,BBB

Materials 7tili.ation chart

Hori.ontal + in 2B,BBB

ertical to suit

ecommended $ocument &i.es

The following si.es are recommended when preparing documents*

$rawing &i.e 6riginals 1+ 3referred

Tender $ocuments 14 (1+ reduced)

6ther $ocuments 15

%1 DE.(R&-RE$ FROM $&(ND(RD$

"t is anticipated that there may e situations where the designer will e compelled todeviate from these standards* 1n e#ample of a $eparture from &tandard could e the

use of a gradient greater than the asolute ma#imum value and also the use of radiusless than the allowale minimum for any specified class of road* Where the designer departs from a standard, he must otain written approval and authori.ation from the=ngineer!"n!Chief of MoWHC* The $esigner shall sumit the following information tothe =ngineer!"n!Chief

The numer, name, and description of the road

The facet of design for which a $eparture from &tandards is desiredA

1 description of the standard, including normal value, and the value of the

$eparture from &tandards The reason for the $eparture from &tandards, and

1ny mitigation to e applied in the interests of safety*

The $esigner must sumit all ma0or and minor $epartures from the &tandards and hisproposal for approval* "f the proposed departures from the &tandards are acceptale,the departures from the &tandards will e given approval y the =ngineer!"n!Chief*

%! DEF'N'&'ON$ (ND ())RE7'(&'ON$

8ist of areviations and definitions, relevant to geometric design as well asterminologies used for cross I section, hori.ontal curve, superelevation, are includedhere*

%5





())RE7'(&'ON$

(

((D& 1verage 1nnual $aily Traffic

(($H&O 1merican 1ssociation of &tate Highway and Transportation 6fficials

(D& 1verage $aily Traffic

)

)7C :eginning of ertical Curve

C

C(DD Computer!1ided $esign and $rafting

C* Center line

CM. Corrugated metal pipe

C$ Curve to spiral

CWW Carriageway width

D

DH7 $aily High olume

D$ $esign standard

D&M $igital Terrain Model

D7 $esign vehicle

E

E =#ternal distance

E7C =nd of ertical Curve

F

F$E ull superelevation

"

".$ %loal 3ositioning &ystem

%9





H

H(* Hori.ontal 1lignment 8istingHCM Highway Capacity Manual

'

*

*C 8ong chord

*O$ 8evel of service

*W 8ane width

M

MOFED Ministry of inance and =conomic $evelopment

M-&CD Manual on 7niform Traffic Control $evices

.

.C 3oint of Curvature

.CN 3ro0ect Concept ;ote

.' 3oint of "ntersection

.'. 3ulic "nvestment 3lan

.O& 3oint of Tangent

.$D 3assing &ight $istance

.& 3oint of Tangency

.7' 3oint of ertical "ntersection

R

RC. einforced concrete pipe

RFC$ oad unctional Classification &ystem

ROW ight!of!way

R. eference 3oint

R.$D educed 3assing &ight $istance

RRW oad reserve width

%>





$

$ &houlder

$$D &topping &ight $istance

&

&R* Transport esearch 8aoratory

&RR* Transport and oad esearch 8aoratory

7

7.' ertical 3oint of "ntersection

%?





DEF'N'&'ON$

(

(ccess

Way wherey the owner or occupier of any land has access to a pulic road,

whether directly or across land lying etween his sand and such pulic road*

(ccess contro#

The condition wherey the road agency either partially or fully controls theright of autting owners or occupiers to direct access to and from a pulichighway or road*

(cce#eration *ane

1n au#iliary lane to enale a vehicle to increase its speed so that it canmore safely merge with through traffic*

(t4"rade Junction

unction where all roadways 0oin or cross at the same level*

(u5i#iary *ane

3art of the roadway ad0oining the carriageway for parking, speed change,turning, storage for turning, weaving, truck climing, and for other purposessupplementary to through traffic movement*

(8erage (nnua# Dai#y &raffic 9((D&:

Total yearly traffic volume in oth directions divided y the numer of days in the year*

(8erage Dai#y &raffic 9(D&:

Total numer of vehicles (traffic volume) during a given time period in wholedays greater than one day and less than one year divided y the numer of days in that time period*

(8erage running s/eed

The distance summation for all vehicles divided y the running time

summation for all vehicles* 1lso referred to as space mean speed whereastime speed is simply the average of all recorded speeds*

(5is of rotation

The line aout which the pavement is rotated to superelevate the roadway*

)

)ack $#o/e

1rea proceeding from ditch ottom to the limit of the earthworks*

%@





)arricade

1 portale or fi#ed arrier used to close all or a part of a road to vehicular traffic*

)orro6

Material not otained from roadway e#cavation ut secured y widening cuts,

flattening cut ack slopes, e#cavating from sources ad0acent to the roadwithin the right!of!way, or from selected orrow pits as may e noted on theplans*

)o##ard

1 device placed on a street refuge or traffic island to provide a measureof protection for pedestrians and to warn drivers of these ostructions* "talso usually indicates y means of a traffic sign the direction to e takeny vehicles* The device is generally illuminated at night*

)ridge

1 structure erected with a deck for carrying traffic over or under anostruction and with a clear span of si# meters or more* Where the clear span is less than si# meters, reference is to a culvert*

)us *ay4)yes

8ay!y reserved for pulic service vehicles*)y/ass

1 road on the fringe of a town or village to enale through traffic to avoidcongested areas or other ostructions to movement*

C

Cam3er

The slope from a high point (typically at the center line of a road) across thelanes of a highway* "t is also called Crossfall*

Ca/acity

The ma#imum numer of vehicles that can pass a point on a road or in adesignated lane in one hour without the density eing so great as to causeunreasonale delay or restrict the driver/s freedom to maneuver under prevailing roadway and traffic conditions*

Ca//ing *ayer

1 layer of selected fill material placed on the topmost emankment layer or the ottom of e#cavation*

Carriage6ay

3art of the roadway including the various traffic lanes and au#iliary lanes ute#cluding shoulders*

Center *ane

6n a dual three!lane road, the middle lane of the three lanes in onedirection*

%<





Center#ine

1#is along the middle of the road*

Centra# Reser8e

1n area separating the carriageways of a dual carriageway road*

Circu#ar Cur8e

7sual curve configuration used for hori.ontal curves*

Channe#ising 's#and

1 traffic island located in the carriageway area to control and direct specifictraffic movements to definite channels*

Channe#isation

The separation or regulation of conflicting traffic movements into definite

paths of travel y the use of pavement markings, raised islands, or other suitale means to facilitate the safe and orderly movement of traffic, othvehicular and pedestrian*

Channe#ised Junction

1n at!grade 0unction in which traffic is directed into definite paths y islandand road marking

C#ear ;one

7nencumered roadside recovery area*

C#im3ing *ane

1n au#iliary lane in the upgrade direction for use y slow moving vehicles andto facilitate overtaking, therey maintaining capacity and freedom of operationon the carriageway*

C#o8er#eaf

1 four!way interchange in which inner loops are provided for movements anddirect outer connections for right!turn!movements* 1 cloverleaf has ramps for turning movements

Coefficient of Friction

atio of the frictional force on the vehicle and the component of the weight of the vehicle perpendicular to the frictional force*

Co##ector Roads

&econdary oads linking locally important centers to each other, to moreimportant centers or to higher class roads*

Com/ound Cur8e

Curve consisting of two or more arcs of different radii curving in the samedirection and having a common tangent or transition curve where they meet*

%+B





Contro# of (ccess

Conditions where the right of owners or occupants of ad0oining land or other persons to access, light, air or view in connection with a road is fully or partially controlled y pulic authority*

Crest3eak formed y the 0unction of two gradients*

Crest Cur8e

Conve# vertical curve with the intersection point of the tangents aove theroad level*

Criterion 1 yardstick according to which some or other quality of the road can emeasured* %uideline values are specific numerical values of the criterion*

Critica# $#o/e

&ide slope on which a vehicle is likely to overturn*

Critica# #ength of grade

The ma#imum length of a specific upgrade on which a loaded truck canoperate without an unreasonale reduction in speed* 1 speed reduction of +9 kmFh or more is considered 'unreasonale-*

Crossfa##

The tilt or transverse inclination of the cross!section of a carriageway which isnot camered, e#pressed as a percentage*

Cross4Roads

our!leg 0unction formed y the intersection of two roads at appro#imatelyright angles*

Cross4$ection

ertical section showing the elevation of the e#isting ground, ground data andrecommended works, usually at right angles to the centerline*

Cro6nHighest portion of the cross!section of a camered roadway*

Cur3:order of stone, concrete or other rigid material formed at the edge of theroadway or footway*

Cyc#e Way

Way or part of a road for use only y pedal cycles*

D

Dece#eration *ane

1n au#iliary lane to enale a vehicle leaving the through traffic stream toreduce speed without interfering with other traffic*

%++





Def#ection (ng#e

&uccessive angles from a tangent sutending a chord and used in setting outcurves*

De/arture from $tandards

$eviation from values given in the reference, requiring prior approval of the

Ministry (MoWHC)*

Design Ca/acity

Ma#imum numer of vehicles that can pass over a lane or a roadway during agiven time period without operating conditions falling elow a pre!selecteddesign level*

Design $/eed

1 speed selected and used for design and which links road function, trafficflow and terrain to the design parameters of sight distances, curvature, andsuperelevation to ensure that a driver is presented with a reasonaly safe

and consistent speed environment* "t is in practice, most roads will only econstrained to minimum parameter values over short sections or on specificgeometric elements*

Design &raffic 7o#ume

;umer of vehicles or persons that pass over a given section of a lane or roadway during a time period of one hour or more*

Design 7ehic#e

ehicle whose physical characteristics and proportions are used in settinggeometric design*

Design 7o#ume

olume determined for use in design, representing traffic e#pected to use theroad*

Diamond Junction

1 four!way interchange with a single one!way ramp in each quadrant* 1llright!turns are made at grade on the minor road*

Di8erging

Movement of a vehicle out of a traffic stream*Di8ersion

1n alternative route for traffic to avoid congestion, ostruction or other ha.ard*

Di8ided Road

oad in which there are two physically separated roadways reserved for traveling in opposite directions*

Dua# Carriage6ay Road

1 road in which there are two physically separated carriageways reserved for travelling in opposite directions

E

%+2





Economica# *imit of Hau#

$istance through which it is more economical to haul e#cavated material thanto waste and orrow*

Em3ankment

That portion of the road prism composed of approved fill material, which lies

aove the original ground and is ounded y the side slopes, e#tendingdownwards and outwards from the outer shoulder reakpoints and on whichthe pavement is constructed*

Escar/ment 9&errain:

&teep country inclusive of switchack sections and side hill traversesAtransverse terrain slope J ?B percent*

Eye Height

1ssumed height of driversK eyes aove the surface of the roadway used for the purpose of determining sight distances*

F

Feeder Road

8owest level of road in the network hierarchy with the function of linking trafficto and from rural areas, either directly to ad0acent uran centers, or to theCollector road network*

Fi##Material which is used for the construction of emankments*

Fi#tering

The permitted movement of one or more lines of traffic streams while theremaining lines are stopped*

F#at 9&errain:

lat terrain with largely unrestricted hori.ontal and vertical alignmentAtransverse terrain slope up to 9 percent*

F#ush Cur3

1 concrete structure, usually continuous at the edges of the carriagewayandFor paved shoulder, providing them with lateral support* "t is usually flushwith their surfaces*

Free Hau#

Ma#imum distance through which e#cavated material may e transportedwithout added cost aove the unit id price*

Foot6ay

3ortion of a road reserved e#clusively for pedestrians*

%+4





Fork4<unction

1 L!0unction in which one the arm of the L does not deviate from the stem*

"

"eometric 9Design: $tandards

%uidelines for limiting values of road alignment and cross!section design*

"rade $e/arated Junction

unction where two roads cross at different levels and are connected yramps*

"rade $e/aration

Crossing of two roads, or a road and a railway at different levels*

"radient

1 rate of rise or fall on any length of road with respect to the hori.ontal* "t isusually e#pressed as a percentage of vertical rise or fall in meters F +BBmeters of hori.ontal distance*

"uardrai#

Continuous arrier erected alongside a road to prevent traffic fromaccidentally leaving the roadway or from crossing the median*

"yratory &raffic

ehicular traffic flowing round a system of one!way streets or a roundaout*

"yratory $ystem

1 system of one!way carriageways which together allow a continuouspassage of traffic around a central area which may or may not containuildings*

HHa#f4c#o8er#eaf

1 four!way interchange in which loops and outer connections are provided intwo quadrants to given grade separation to the ma0or road, ut on the minor road the right!turning movements take place at grade*

Horionta# (#ignment

$irection and course of the road centerline in plan*

Horionta# C#earance

8ateral clearance etween the edge of shoulder and ostructions*

Horionta# Cur8e

Curve in plan*

%+5





'

'nterchange

;etwork of roads at the approaches to a 0unction at different levels thatpermits traffic movement from one to the other one or more roadways or roads*

J

Junction 9'ntersection:

a) Common .one of two or more roads allowing vehicles to pass from one tothe otherA

) Meeting of one road with another*

==48a#ue

atio of the minimum length of vertical crest curve in meters to the algeraic

difference in percentage gradients ad0oining the curve*

*

*ane&trip of roadway intended to accommodate a single line of moving vehicles*

*ay43y3art of the road set aside for vehicles to draw out of the traffic lanes for shortperiods*

*eft 4Hand *ane

6n a dual roadway, the traffic lane nearest to the verge or shoulder*

*eft &urn *ane

1n au#iliary lane to accommodate deceleration and storage of left!turningvehicles at 0unctions*

*eft4right $tagger

1 cross!roads at which a driver intending to cross a ma0or road, turns to hisleft on entering the intersecting road, and then to his right in order to continue

on his route*

*e8e# of $er8ice

ualitative rating of the effectiveness of a road in serving traffic, measured interms of operating conditions*

*imited (ccess Road

oad with right of access only at a limited numer of places*

*ink Road

;ational oad linking nationally important centers*

%+9





*oca# Road

oad (or street) primarily for access to ad0oining property* "t may or may note a classified road*

*ongitudina# .rofi#e

6utline of a vertical section of the ground, ground data and recommended

works along the centerline*

M

Main (ccess Road

3rimary oad linking provincially important centers to each other or to higher class roads*

Marker .ost

3ost, generally fitted with reflective material or small reflecting studs, ut notusually lighted, erected off the roadway to give warning or guidance to traffic*

Meeting $ight Distance

$istance required to enale the drivers of two vehicles traveling in oppositedirections on a two!way road with insufficient width for passing to ring their vehicles to a safe stop after ecoming visile to each other* "t is the sum of the stopping sight distances for the two vehicles plus a short safety distance*

Median 1rea etween the two carriageways of a dual carriageway road* "t e#cludesthe inside shoulders*

Merging

Movement of a vehicle or vehicles into a traffic stream*

Mountainous 9terrain:

Terrain that is rugged and very hilly with sustantial restrictions in othhori.ontal and vertical alignmentA transverse terrain slope 29!?9 percent*

Motor6ay

1 road having dual carriageways and shoulders, with complete gradeseparation* "t is for the e#clusive use of prescried classes of motor vehicles*

Mu#ti4#eg Junction

1 0unction with five or more legs*

%+>





N

Net6ork 9Hierarchy:

Classification of roads according to "nternational Trunk, ;ational Trunk,3rimary, &econdary, and Minor*

Nonreco8era3#e $#o/e

Transversile side slope, where the motorist is generally unale to stop or return to the roadway*

Norma# Crossfa##

$ifference in level measured traversely across the surface of the roadway*

O

O3<ect Height

1ssumed height of a notional o0ect on the surface of the roadway used for the purpose of determining sight distance*

O/erating $/eed

Highest overall speed at which a driver can travel on a given road under favorale weather conditions and under prevailing traffic conditions without atany time e#ceeding the safe speed as determined y the design speed on asection!y!section asis*

O/timum $/eed

The speed at which the ma#imum possile traffic flow (traffic capacity) can e

attained*

O8er/ass%rade separation where the su0ect road passes over an intersecting road or railway*

.

.arking )ay

1rea provided for ta#is and other vehicles to stop outside of the roadway*

.assenger Car -nit 9.C-:

1 unit of road traffic, equivalent for capacity purposes to one normal privatecar* The private car is thus the unit and other vehicles are converted to thesame unit y a factor depending on their type and circumstances*

.assing )ay

Widened section of an otherwise single lane road where a vehicle may moveover to enale another vehicle to pass*

.assing $ight Distance

Minimum sight distance on two!way single roadway roads that must eavailale to enale the driver of one vehicle to pass another vehicle safelyand comfortaly without interfering with the speed of an oncoming vehicle

%+?





traveling at the design speed, should it come into view after the overtakingmaneuver is started*

.a8ement

1 multi!layered hori.ontal structure which is constructed for the purpose of carrying traffic*

.a8ement *ayers

The layers of different materials, which comprise the pavement structure*

.eak Hour &raffic

The highest numer of vehicles found to e passing over a section of lane or carriageway during >B consecutive minutes*

.edestrian Crossing

Transverse strip of roadway intended for the use of pedestrians crossing theroad* The crossing may e uncontrolled or controlled*

.edestrian "uard Rai#

1 protective fence etween two carriageways to discourage pedestrians fromcrossing the road*

.edestrian Refuge

aised platform or a guarded area so sited in the roadway as to divide thestreams of traffic and to provide a safety area for pedestrians*

.oint of 'ntersection 9.':

The internal angle formed y two successive straights*

R

Ram/

a) "nclined section of roadway over which traffic passes for the primarypurpose of ascending or descending so as to make connections with other roadwaysA

) "nterconnecting length of road of a traffic interchange or any connectionetween roads of different levels, on which vehicles may enter or leave adesignated road*

Ram/ &ermina#

The general area where a ramp connects with a through carriageway*

Reco8era3#e $#o/e

&ide slope of limited grade such that a motorist can generally return to theroadway*

Re8erse Cur8e

Composite curve consisting of two arcs or transitions curving in oppositedirections*

%+@





Right Hand *ane

6n a dual roadway, the traffic lane nearest to the median or near to thecentral reserve*

Right4#eft $tagger

1 cross!roads at which a driver, intending to cross a ma0or road turns to his

right on entering the intersecting road, and then to his left in order to continueon his route*

Right4&urn *ane

1u#iliary lane to accommodate deceleration and storage of right! turningvehicles at 0unctions*

Right4of4Way

&trip of land legally awarded to the oads 1gency (MoWHC), in which theroad is or will e situated and where no other work or construction may takeplace without permission from the oads 1gency (MoWHC)* The width of the

road reserve is measured at right angles to the centerline*Ring Road

1 road around an uran area enaling traffic to avoid it*

RoadWay for vehicles and for other types of traffic which may or may not elawfully usale y all traffic*

Road )ed

The natural in!situ material on which the emankment or capping layers areto e constructed*

Road Functiona# C#assification

Classification of roads according to service provided in terms of the roadhierarchy*

Road .rism

The cross sectional area ounded y the original ground level and the sidesof slopes in cuttings and emankments e#cluding the pavement*

Road6ay

3art of the road comprising the carriageway, shoulders and median*

Road6ay Width

Measurement at right angle to the centerline incorporating carriageway,shoulders and, when applicale, median*

Roadside

%eneral term denoting the areas ad0oining the outer edges of the shoulders*

Road Width

1 measurement at right angle to the centreline incorporating travelled way,shoulders and, when applicale, central reserve*

Road Reser8e

%+<





1 strip of land legally awarded to the oad 1gency (MoWHC), in which theroad is or will e situated and where no other work or construction may takeplace without permission from the oad 1gency (MoWHC)* The width of theroad reserve is measured at right angles to the centerline*

Ro##ing 9&errain:

Terrain with low hills introducing moderate levels of rise and fall with somerestrictions on vertical alignmentA traverse terrain slope 9!2B percent*

Rounda3out

oad 0unction designed for movement of traffic in one direction around acentral island*

$

$afety Rest (rea

oadside area with parking facilities for the motorist to stop and rest*

$ag Cur8e

Concave vertical curve with the intersection point of the tangents elow theroad level*

$cenic O8er#ook

&afety rest area primarily for viewing scenery*

$er8ice (rea

8and with access to and from a road allocated for the provision of certainamenities and services*

$er8ice Road

1 susidiary road connecting a principal road with ad0acent uildings or properties facing thereon, and connected with the principal road only atselected points*

$hift

The lateral displacement of a circular curve, measured along the radius,consequent upon the introduction of a transition curve*

$hou#der

3art of the road outside the carriageway, ut at sustantially the same level,for accommodation of stopped vehicles for emergency use, and for lateralsupport of the carriageway *

$hou#der )reak/oint

The point on a cross section at which the e#tended flat planes of the surfaceof the shoulder and the outside slope of the fill and pavement intersect*

$ide Drain

1 longitudinal drain offset from, and parallel to, the carriageway*

%2B





$ide $#o/e

1rea etween the outer edge of shoulder or hinge point and the ditch ottom*

$ight Distance

$istance visile to the driver of a passenger car measured along the normaltravel path of a roadway to the roadway surface or to a specified height

aove the roadway surface, when the view is unostructed y traffic*

$ing#e *ane Road

oad consisting of a single traffic lane serving oth directions, with passingays*

$cissors Junction

1 four!leg 0unction formed y the olique intersection of two roads*

$/eedate of movement of vehicular traffic or of specified components of traffic,

e#pressed in kilometers per hour (kmFh)*

$/eed )um/

$evice for controlling the speed of vehicles, consisting of a ar or recess onthe roadway*

$to//ing $ight Distance

$istance required y a driver of a vehicle traveling at a given speed, to ringhis vehicle to a stop after an o0ect on the roadway ecomes visile* "tincludes the distance traveled during the perception and reaction times andthe vehicle raking distance*

$treet

1 road which has ecome partly or wholly defined y uildings estalishedalong one or oth frontages*

$u/ere#e8ation

"nward tilt or transverse inclination given to the cross section of a roadwaythroughout the length of a hori.ontal curve to reduce the effects of centrifugalforce on a moving vehicleA e#pressed as a percentage*

$u/ere#e8ation Run4off

8ength of road over which superelevation is reduced from its ma#imum valueto .ero*

$6itch3acks

&equence of sharp curves at or near minimum radius employed to traverse amountainous or escarpment terrain section*

&

&4Junction

Three!leg 0unction in the general form of a T*

&angent

%2+





3ortion of a hori.ontal alignment of straight geometrics*

&a/er

Transition length etween a passing place, au#iliary lane or climing lane andthe standard roadway*

&enth, &6entieth, &hirtieth, etc Highest (nnua# Hour#y 7o#ume

The hourly traffic volume on a given section of a road that is e#ceeded y <,+<, 2<, etc*, respectively, hourly volumes during a designated year*

&hrough Road

oad primarily for through traffic in relation to the area considered, on whichvehicular traffic is usually given priority over the traffic on intersecting roads* "tmay or may not e a classified road*

&rafficehicles, pedestrians and animals traveling along a route*

&raffic Ca/acity 9Ca/acity:

Ma#imum numer of vehicles which has a reasonale e#pectation of passingover a given section of a lane or a roadway in one direction or in othdirections for a two!lane single roadway road, during a given time periodunder prevailing road and traffic conditions

&raffic F#o6

;umer of vehicles or persons that pass a specific point in a stated time, inoth directions unless otherwise stated*

&raffic *ane

3art of a carriageway intended for a single stream of traffic in one direction,which has normally een demarcated as such y road markings*

&raffic 's#and

Central or susidiary area raised or marked on the roadway, generally at aroad 0unction, shaped and placed so as to direct traffic movement*

&raffic 7o#ume

The numer of vehicles or persons that pass over a given section of a lane or

a roadway during a time period of one hour or more* olume is usuallye#pressed in one of the following terms

&ransition Cur8e

Curve whose radius changes continuously along its length, used for thepurpose of connecting a tangent with a circular arc or two circular areas of different radii*

&ransition *ength

8ength of the transition curve*

%22





&ra8e##ed Way

That part of the carriageway used for the movement of vehicles, e#clusive of au#iliary lanes, us!ays, etc*

&rum/et Junction

1 grade separated T!0unction*

&urning *anes

8anes which separate turning vehicles from the through traffic lanes*

&y/ica# Cross4$ection

Cross!section of a road showing standard dimensional details and features of construction*

-

-nder/ass

1 grade separation where the su0ect road passes under an intersecting roador railway*

-ncontro##ed .edestrian Crossing 9;e3ra4crossing:

1 pedestrian crossing marked y a series of white longitudinal strips e#tendedtransversely across the width of the carriageway and accompanied y trafficsign (N3edestrian CrossingN), where a pedestrian has priority over all vehiclesy which he would e impeded*

7

7erge

That part of the road outside the carriageway and generally at sustantiallythe same level* "t may contain footpaths, cycle tracks or ditches*

7ertica# (#ignment

$irection of the centerline of a road in profile*

7ertica# Cur8e

Curve on the longitudinal profile of a road, normally paraolic*

7isi3i#ity $/#ay

1 triangular area ordered y intersecting roads and kept free of ostructions(e#cept essential traffic signs) to enale a driver who is required to give wayto have unostructed visiility along the ma0or road*

W

Waste

Material e#cavated from roadway cuts ut not required for making theemankments* "t must e pointed out that this material is not necessarilywasted as the word implies, ut can e used in widening emankments,

flattening slopes, or filling ditches or depressions for erosion control*

%24





Wea8ing

Movement in the same general direction of vehicles within two or more trafficstreams intersecting at a shallow angle so that the vehicles in one streamcross other streams gradually*

Wea8ing *ength

The length of carriageway in which weaving may take place*

Wea8ing $ection

The area of carriageway in which weaving may take place*

>4<unction

1 three!leg 0unction in the general form of a L*

%25





&ERM'NO*O"'E$

Road Cross $ection E#ements

%29




Construction W idth (Varies)

Road Way Width

a) &ingle Carriageway roads (ural &ection)

) $ual Carriageway roads (ural &ection)

Carriageway

VergeExisting Ground

S i d e

D i t c h

( B a c

k S l o p e )

( S i d e S l o p e )

e !

a n k e n t

S l o p

e o "

B e r

# r a " " i c $ a n e

# r a " " i c $ a n e

S h o u l d e r

S l o p

e o " c u t t i n g

S i d e

D i t c h

S h o u l d e r

C u t % o " " d i t c h

B e r

Roadway Width

Carriageway &edian Carriageway

S i d e D i t c h

# r a " " i c $ a n e

# r a " " i c $ a n e

# r a " " i c $ a n e

# r a " " i c $ a n e

S h o u l d e r

C*


Cross $ection &ermino#ogy

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'

α

Circular length


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&LM:68 $=&C"3T"6;

T&&CC&&T3"8&8C

∆

Om

On Ln

α

T8CC

adius of circular curveTangent to spiralspiral to curveCurve to spiral&piral to tangentpoint of "ntersectionlength of spiral8ength of circular curve&hift 1sisa of center pointCoordinate at station ;o*$eflection 1ngleTangent 8engthTotal curve length (circle P spiral)

HOR';ON&(* C-R7E



e

eBE2*9Q

e


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&LM:68 $=&C"3T"6;

e6

e∆&

CT =CC C8

;ormal crossfall

&uper elevation

ate of change of super elevation

Clothoid to Tangent=nd of circle to clothoidCenterline of road

$-.ERE*E7(&'ON



$VC

#($VC)*

"y

'

∆gQ

V+,

V+, -o.

St ..........

/t ..........

R0 .. ........

$VC . .........

∆g **********

" ...............

B V C

S t

/ t

/ t

S t

E V C


7ER&'C(* C-R7E

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$ym3o# Descri/tion $ym3o# Descri/tion

g3"

&tHtv8vc

∆g

%radient (Q)3oint of intersection of vertical curve&tation chainageHeight aove sea level (m)=quivalent radius of vertical curve (m)8ength of vertical curve (m) 1lgeraic difference in gradients (Q)

:vc=vc

T

y#f

8s8m8p

:eginning of vertical curve=nd of vertical curveTangent length of vertical curveTangent offset (vertical)Hori.ontal length in planCenter correction&topping sight distanceMeeting sight distance3assing sight distance

section 1.doc

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