Author Archives: roadnotes

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).

“Findability” and road design standards

I have just published some notes on “side friction”, which you can download (for example) from Academia. The document has a “discussion” section which in part looks at how current design standards fail their users. Examples of these failures include … Continue reading

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Road design and older drivers

There used to be a saying that road designs were a function of the road, the vehicle and the driver. It now appears that there are different types of driver, and some standards are appearing which suggest different values for … Continue reading

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ARRB resources

The ARRB is the Australian Road Research Board. Its website says that it “exists to serve the research needs of its Members, and maintain its reputation as a national interest, applied research organisation. Hence, our vision is born: to deliver … Continue reading

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London – Doubtful project development procedures

On the 7th April 2017 the Independent newspaper reported on what it described as Dame Margaret Hodge’s “damning” independent review of the London Garden Bridge project. This project, as London’s official website says: “….is a proposed footbridge and public garden … 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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