Category Archives: highway design standards

More notes on road design standards (1)

Many countries publish “standards“, notes, advice and requirements related to the geometric design of roads. But as I have argued before (see for example here) there are too many of these standards. What makes life more difficult for engineers is … Continue reading

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Notes on “design speed”

Speed – and in particular design speed – is a key parameter in determining values for a number of highway geometric features in highway design. Examples include horizontal radius and stopping sight distance. There also seems to be a  relationship between … Continue reading

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Inter-vehicle gap

The discussion on the longitudinal gap between vehicles is well-established; increased speed means increased gap. But this only covers the gap in the direction of travel. What information is there on the lateral gap – the one between vehicles at … Continue reading

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Turkish delight

In a recent post I expressed some doubt about the usefulness of the UK’s TD 9/93 (part of the “Design Manual for Roads and Bridges” (DMRB)). If any users of TD 9/93 also have some doubts, help may be available … Continue reading

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UK design guideline TD 9/93 – time for a rethink ?

The UK’s principal guideline on the design of roads is the “Design Manual for Roads and Bridges” (DMRB).  Wikipedia says the DMRB “is a series of 15 volumes that provide standards, advice notes and other documents relating to the design, … Continue reading

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Parameters (3) vehicle type

So far I have discussed the concept of fundamental parameters in highway geometric design (for example, here) and the fundamental parameter “road type“. This post covers the fundamental parameter “vehicle type“. Vehicle type relates directly to design vehicles – the … Continue reading

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Parameters (2) road type

I began a discussion about fundamental parameters in highway geometric design recently. The first parameter in my list is road type.  A feature of “road types” is  that they are associated with specific details of highway geometric parameters in all … Continue reading

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Criticism of current standards

The authors Broeren, Uittenbogerd, Groot, Ruijs gave a paper at the ISHGD 2015 (5th International symposium on highway geometric design). The paper has the title “Insight in horizontal curves – fundamental research on behalf of the update of the Dutch … Continue reading

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Road design – the vehicle environment

This is the third of three posts which refer to the presentation by Dr. John Rolt of the UK’s TRL (ref. 2211). In the previous post, I said that “It is easy to read through a document with road design standards, … Continue reading

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3D road design

Two authors from the National Technical University of Athens recently published a paper on 3D road design. You can find copies of the paper online. It is called”Three dimensional road design by applying differential geometry and conventional design approach criteria” … Continue reading

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