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.
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.
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.
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.
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.
All 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?”
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