gta-301 dimensions of vehicles
DESCRIPTION
Discussion paper. Highway engineering is a coordinated interplay between: road users, vehicles, roads, and land uses. To begin to understand and design for vehicles, one thing the engineer needs to know is the dimensions of the vehicleTRANSCRIPT
Global Transport Atlas
GTA-301 Dimensions of Vehicles Series 3- Discussion Papers
GTA-301 version 01 June 2012 Page 1
highways, roads, vehicles, dimensions
Highway engineering is a coordinated interplay between: road users, vehicles, roads, and land uses. To begin to understand and design for vehicles, one thing the engineer needs to know is the dimensions of the vehicles.
Source: Robert Bartlett
Highway engineers say that when designing a road they need to consider “the road user, the vehicle and the road”. It follows from this that the designer of a road (or any other transport facility) needs to know the dimensions of the vehicles which will use it.
However, the dimensions of vehicles are not constant. They vary of course, by vehicle class (so e.g. a car is wider than a bicycle), they vary by vehicle type (so that e.g. a tricycle is wider than a bicycle), they vary over time (so that an HGV today is longer than an HGV of the 1950’s) - and they vary depending on the state of the vehicle, or how the vehicle is being used.
With cars for example, quoted width usually ignores wing mirrors, quoted height ignores roof racks, and quoted length ignores the space required to access the car boot. Cars take up less width when they are in motion (since the doors are supposed to stay shut) than when they are stopped (when people need space to get into and out of them).
Designers should consider dimensions for at least four vehicle states: the basic vehicle, the vehicle with accessories, the vehicle in motion (“vehicle-in-use”), and the vehicle at rest. Further work vehicles such as small delivery vans need more clear space when parked/delivering than normal vehicles. This applies to all vehicle types - for example, it is likely that
work bikes will need more clear space in some circumstances than bikes in "normal" use.
Proposition
The basic dimensions of vehicles include length, width and height (L, W, H).
Highway engineers need values for these dimensions based on the state or use of the vehicle (H1, H2.... ; W1, W2....; L1, L2....)
Vehicle state Description
1. the basic vehicle basic cycle without rider or accessories
2. the vehicle with accessories
cycle with e.g. side panniers, basket, mirrors, child seat etc.
3. vehicle in motion cycle with accessories and rider
4. vehicle at rest cycle with enough clear space to allow rider to mount it.
1. Basic dimensions
Global Transport AtlasSeries 3 - Discussion PapersGTA-301 - Dimensions of Vehicles
GTA-301 version 01 June 2012 Page 2
To provide some dimensional background to the design of transport facilities, engineers break down the global pool of road vehicles into a number of different types or classes. This process can be termed "classification". After all the physical size and speed of a lorry is quite different to those of a bicycle, the size and speed of a car quite different to those of a pedestrian. For example, for design purposes one classification road vehicles could be put into one of the following classes:
1. pedestrians
2. bikes
3. passenger cars
4. buses
5. goods vehicles
Perhaps at a global scale this simple, 1-level classification is enough. But in practice the "class" called bicycles contains vehicles with widely different sizes, speeds etc. In fact, using the word bicycle is itself incorrect (it implies 'two wheels'). Bikes in use on the roads - in Europe as well as the rest of the world - can have from 1 to 4 wheels or more, carry one to 4 or more persons and can even be used as goods vehicles. Motorised goods vehicles can range in size from the "Smart" minicars to Australia's goods vehicle trains.
It would be appropriate to take the classification to a seccond level, where these different dimensions etc. would be more obvious and could be more taken into account.
For example
2. bikes
2.1 bicycles
2.2 trikes
2.3 reclining bikes
2.4 bike+trailer
.... etc.
One concern is that if engineers are only given a single-level classification (all bikes = 2-wheeled bicycles) then they only design for the "2-wheeled bicycle". All other bike users risk being presented with (for example) a bike lane which is too narrow to be safe.
3-wheel work bike ("guta") Tanzania4-wheel bike+trailer in GermanyWork bike, Albania
2. Vehicle classification
Global Transport AtlasSeries 3 - Discussion PapersGTA-301 - Dimensions of Vehicles
GTA-301 version 01 June 2012 Page 3
Over the course of time, authorities in different countries involved in highway design have published values for the dimensions of "standard" design vehicles. The idea is that these dimensions should be used in the design of transport facilities in that country.To a more or less limited extent these publications also involve a system of vehicle classification which has 2-or more layers (see table 1).
However a closer view of such "vehicle classifications" and "standard dimensions" suggests that whilst the concept may be useful in theory, as presently implemented it may present a number of problems. For example:
The classifications are incomplete - they do not cover every vehicle type on the country's roads
There is no obvious link between (a) a vehicle class/type and (b) the road facility for which this vehicle type should be used in the design
There is no obvious link between (b) a road type and (a) the standard vehicle(s) which should be considered in its design
Some vehicles will be larger than the standard vehicle. This is because the standard is usually not based on the largest possible vehicle of the type concerned, but on some representative portion of the overall vehicle population (an average value, the 85%ile largest vehicle etc.)
Use of "standard" vehicle dimensions implies that vehicle dimensions do not change with time (or at least, over the lifetime of a piece of highway infrastructure)
Conversely, if the standard dimensions are revised there is an implication that even recently built roads are no longer appropriately designed
The values used for standard dimensions may not be robust. For example, cars are vehicles which are manufactured and sold on a global basis rather than a national basis. It would be expected therefore that different sources would propose similar values for the standard dimensions of a car.
This is not the case (see e.g. table 2).
Extra for heightThe basic car Extra for length
3. Design vehicles
Global Transport AtlasSeries 3 - Discussion PapersGTA-301 - Dimensions of Vehicles
GTA-301 version 01 June 2012 Page 4
We can argue that vehicle dimensions do change with location - and over a very short space of time. But it all depends on the scale which is being considered.
At a macro scale (regional, national, international road networks for example), the dimensions of a standard car can be taken as constant. There would also seem to be little reason to suppose that the dimensions of a "car" differ depending on whether the vehicle is sold in England, Germany, Australia or any other country. There would seem to be little value and little technical justiication for changing the width of a traffic lane in a motorway depending whether the road was in Scotland or Wales (or Bavaria / Berlin).
However at a micro scale there are good reasons to reject the use of one standard dimension for a vehicle type (one value for the "standard" length of a car for example):
a vehicle's dimensions change depending on how it is used (see the example of the 3-wheel work bike "gutas" in Tanzania)
a vehicle's dimensions change with its "state"
the state of the vehicle
the use of the vehicle.
Proposition The engineering dimensions of a transport
infrastructure such as a road or car park should be based on the classes/types and dimensions of the vehicles which use them
The dimensions of a vehicle vary with the vehicle state
At a micro-scale the dimensions of vehicles vary with location
At a macro-level the dimensions of vehicles are the same regardless of location
The classes of vehicle which use the roads in one country are not the same as the classes of vehicle which use the roads in another country
It is possible to develop a global, standard 2-level classification of vehicles
The "fitness for purpose" of a highway facility (footpath or car park) depends partly on whether it is designed for the dimensions of vehicles which will actually use it (vehicle class/type and states)
Tables of typical vehicle dimensions could usefully be prepared for different scales of consideration (global and local) - see outline in table 3 .
4. Scalar dimensions
Global Transport AtlasSeries 3 - Discussion PapersGTA-301 - Dimensions of Vehicles
GTA-301 version 01 June 2012 Page 5
Table 1: details offered for "standard" design vehicles
Document Country, Year
Description Comment
Roads in urban areas UK 1966 gives details of only 3 vehicle types: articulated vehicle, rigid vehicle, large car
scant, 1-level classification
Bemessungsfahrzeuge und Schleppkurven zur Überprüfung der Befahrbarkeit von Verkehrsflächen
Germany, 2001
cars (1 sub-type)
goods vehicles
trucks (3 sub-types)
truck+trailer (1 sub-type)
articulated lorry (1
sub-type)
refuse collection vehicles (3
sub-types)
bus (3-sub-types)
2-level classification
LTN 2/08 cycle infrastructure design
UK 2008 only refers to bikes; gives limited details for 4 sub-types:
conventional bike
bicycle and 850mm wide trailer
bicycle and trailer cycle
tandem
An implicit 2-level classification. There are more than 4 types of bike - for example a notable exception is the cycle rickshaw. These public service vehicles are in use in London and several other cities in the UK
Road planning and design manual, chapter 5 "traffic parameters and human factors"
Australia,2002 12 vehicle classes (not including bikes or pedestrians). Classes have from 1 to 11 sub-types. Class 12 (road trains) describes 10 vehicle types, all with maximum length of 53.5 m.).
An implicit 2-level classification.
Table 2: details offered for "standard" design vehicles
Document Car length Comment
Roads in urban areas 18 ft / 5.48 m. "large car"
Bemessungsfahrzeuge und Schleppkurven zur Überprüfung der Befahrbarkeit von Verkehrsflächen
4.74 m.
Road planning and design manual, chapter 5 "traffic parameters and human factors"
5.0 m. "max. length"
5. Tables
Table 3: suggested structure for the development of sets of vehicle dimensions
macro scale micro-scale
(globally determined values)
locally determined values for the "vehicle states" of:
vehicle class / type Basic vehicle Vehicle with fittings
Vehicle at rest Vehicle in use
Global Transport AtlasSeries 3 - Discussion PapersGTA-301 - Dimensions of Vehicles
GTA-301 version 01 June 2012 Page 6
GTA documents series
Global Transport Atlas is a project with two aims. One is to encourage people around the world to share examples of how they actually use transport in their daily lives. The other is to compare and improve the design of transport infrastructure. There are the following GTA document series:
Series 1 - global transport notes
A collection of papers on transport infrastructure and vehicles from various countries, prepared by various authors and contributors. Typical size 2 to 3 pages.
Series 3 - discussion papers
Papers with arguments and ideas on different aspects of modern transport and transport infrastructure.
Series 7 - Dimensions of vehicles
Transport infrastructure has to be defined with an idea of the size and types of vehicle which will use it. This series looks into the dimensions of different types of vehicle at different periods of time. Papers include technical discussion notes and example dimensions. Typical size 20 pages and more.
Cover notes and Disclaimer
This is a research document. The best efforts have been made to make sure the figures are correct. However no liability can be taken for any of the details, information or analysis in this document.
The layout, look and feel of this document is copyright.
Photographs are copyright of REB unless otherwise stated.
This work is licensed under the Creative Commons Attribution 3.0 License.
History and Change log
Originally published as a google knol and went through a number of revisions. The last one was in 2008.
Version 301.01 (June 2012) - this version takes the google knol material and reformats it as a pdf document.
Contact
Email: [email protected]
About the author:
Robert Bartlett is an experienced transportation and urban development studies engineer with over 25 years of professional experience. Current engineering work: includes technical research in highway design standards and applications in areas such as urban planning and highway engineering. Interests include applied GIS