How long is a car?

Transport facilities such as roads and car parks have to be designed for the vehicles that will use them. For example, the length of a car parking space depends on how long a typical car is. The problem then becomes one of deciding how long is a car. Many design manuals refer to design vehicles (cars, goods vehicles, coaches etc) and give values for the most important dimensions which planners should use for each type of vehicle.

 Car length quoted in design manuals

Generally speaking, wherever they are in the world, people can choose their car from the same large pool of vehicle types. Volkswagen sells its Golf model across the world, and doesn’t change the length of a Golf from country to country. So the “design length” for a car should perhaps be the same whichever country produced the standards. In fact, as table 1 shows, this is not the case. There is a difference of almost 1.5 metres between the smallest and largest design car length in the table.

cars 01

Design manuals which quote car lengths based on vehicle fleets in other countries.

Sometimes a road design manual takes the dimensions for its “design vehicles” from research into the distribution of sizes in its country’s vehicle fleet. But sometimes a manual will simply repeat values quoted in another country’s reference works. If table 1 is any indication, this is not a good idea.

cars 02

Car length changes over time

There is an argument that car length changes over time. Figures available for Austria over the 16 year period between 1987 and 2003 suggest that car lengths have decreased in this period.

cars 03

Car length by type of car

Cars are one “class” of road vehicle. They can be divided into sub-classes, such as a 4-wheel drive, or a luxury car. Typical lengths can be different for each of these car “sub-classes”; and some sub-classes may be more common in some areas than in others.

cars 04

Car length by type of car, alternative

 As part of some separate research work I collected details of car dimensions for (so far) around 140 modern cars, and grouped them into my own set of sub-classes. The figures were taken from brochures and company websites. For the overall group of cars I studied the smallest car length was 2335 mm, the longest was 6171 mm.

cars 05

Comment

cars 06All the above tables refer to the length of a car as it leaves the showroom. The length of a car in use can be quite different. The addition of cycle racks (see image) can add 600mm to the length, the use of towed trailers even more.

Even a temporary change in size can make the car much longer than its showroom length. Putting away the shopping in a supermarket car park can increase the required length by 1000mm (second image).

Maybe the question should not be “what is the typical car length for my country?” but rather “what is the typical car length for the transport facility I am designing?”

cars 07

References

55  Hong Kong, Hong Kong Transport Department “Transport planning and design manual” 2001

148  South Africa, CSIR “GDG – Geometric design guide” 2002

294  Tanzania, Ministry of Works “Road Geometric Design Manual” (2011 ed) 2011

408  Iraq, Ministry of Housing and Construction “Highway design manual” 1982

622  Germany, FGSV “Bemessungsfahrzeuge und Schleppkurven“ 2001

830  Germany, Springer „Parkhäuser – Garagen – Grundlagen, Planung, Betrieb“ 2006

831  USA, AASHTO “A policy on the geometric design of highways and streets” 2011

832  USA, AASHTO “A policy on the geometric design of highways and streets” 2004

876  Bahrain, Ministry of Municipalities & Agriculture “Guidelines for the design of off-street car parking facilities” 2014

892  multi-country, SIECA “Manual Centroamericano de Normas para el Diseño Geométrico de Carreteras, 3ª. Edición, 2011

893  Australia, AS-NZS 2890.1-2004 Appendix A

966  UAE, Abu Dhabi municipality, road section “Abu Dhabi roadway design manual” 1998

1032 Malaysia, REAM, “A guide on geometric design of roads” 2000

1088 multi-country, SIECA, “Manual Centroamericano De Normas Para El Diseño Geométrico De Las Carreteras Regionales” 2004

1155  Albania, “ARDM 2 Road design manual vol. 2 / geometric Design”

1159 Finland, Finland transport agency “Finland standard 30/2013: Road alignment design” 2013

1322 UK Inst Str. Eng “Design recommendations for multi-storey and underground car parks (3rd ed.) 2002

1385 Qatar, MMAA “Qatar highway design manual” 1997

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About roadnotes

Robert Bartlett is an international consultant with over 30 years of professional experience as a highway and traffic engineer with leading companies and organisations in several countries, including Germany, China (Hong Kong), Qatar and the UK. Specialised in urban studies, transport and the use of GIS, research has included new ideas on subjects such as the study of social justice using GIS, the dimensions of vehicles, and comparative geometrics (highways and transport).
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