Tag Archives: highway geometric design

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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Road design – road types

In recent posts I have discussed the idea of the “technical environment” for road design. One of the seven technical factors which I suggest describe this environment is “road type”. 

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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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NMT and a new transport user hierarchy

Not exactly new …. In a previous post (here) I wrote: Non-motorised transport (NMT) is as much a part of road transport systems in countries such as the UK and Holland as it is  in countries such as Uganda and … Continue reading

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Road gradient – (1) definition and vehicle performance

Definition of gradient In terms of the vertical alignment of a road, one of the primary design parameters is gradient. A good definition of gradient is given in (ref. 148), which says:

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Level of service – a concept past its sell by date?

In August 2014 the Streetsblog website published an article (here) which began: Ding, dong…LOS is dead. At least as far as the state of California is concerned.

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PCU factors – are they just pseudoscience ?

Road traffic is made up of a great variety of different types of vehicles – from large articulated lorries and busses, to minicars and bicycles. The different vehicle types have different characteristics – length, or typical speed, or rate of … Continue reading

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Understanding road geometrics (3)

Sometimes adding colour can improve the understanding of technical information. Here are three examples:

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