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re-engineering the space of Trafalgar Square

Professor Bill Hillier, Tim Stonor, Mark David Major and Natasa Spende
September 1998


The Space Syntax Laboratory UCL is part of Sir Norman Foster's team carrying out the World Squares for All project in the centre of London. It advises the team on pedestrian space use and movement and spatial design. In this paper, we describe how the Space Syntax team analysed and modelled the existing pattern of space use and movement in and around Trafalgar Square, and from this evolved proposals for design modifications which would lead to a richer pattern of use there.

Aims of the Team in Trafalgar Square

The aims of the team in Trafalgar Square have been:

a. to make sure the space is accessible and intelligible to all pedestrians, including people living and working in London, people visiting the National Gallery, and tourist visitors

b. to make sure that all the space in the Square is used to some degree, since large, empty spaces always detract from the 'feelgood' factor in a public square

c. to ensure everyday use of the Square throughout the year by Londoners and visitors, as well as ensuring it is safe for special occasions

d. to make sure there is enough space in the Square for all those who would in future benefit from using it.

The Current Pattern of Space use and Movement in the Square

As part of its work on the World Squares for All Project, the Space Syntax Laboratory has undertaken the most detailed survey ever of pedestrian movement and space use in central London. The objective in making this survey has been to establish the current pattern of pedestrian activity in the study area, identify the specific problems faced by pedestrians and, from this analysis, generate design ideas which address these problems and satisfy the overall aims of the project.

In making the survey we have sent teams of trained observers onto the streets of London. They have counted leveles of pedestrian movement in over 300 locations at different times of the day, on different days of the week, and in different seasons of the year (Figure 1).

Figure 1 Pedestrian Activity in Trafalgar Square

The results of our survey provide a comprehensive picture of pedestrian activity and show that the key features of space use in Trafalgar Square are:

a the heart of the Square is used almost exclusively by visitors (the red dots in Figure 1)

visitors are concentrated mainly in the south-east corner of the Square, leaving large, relatively empty areas to the north and west

b there is virtually no movement across the heart of the Square (the thin blue lines in Figure 1). Instead we see Londoners moving around the outside pavements of the Square (with some movement across the inside, southern pavement) and visitors meandering slowly within the Square

c there is much 'informal' road crossing by visitors, especially from the south side of Trafalgar Square in order to get to the best views from the King Charles traffic island (the thick green lines in Figure 1)

d there is almost no stationary use of the Square by Londoners. Instead, most Londoners walk around the edges of the Square than across it. In doing so they face major delays at pedestrian crossings. Many cross 'illegally' when faced with the choice of waiting

e the upper level space on the north side of the Square is virtually unused, either for movement or stationary activity.

Why the Square Works this Way

At first sight, the main problem of Trafalgar Square appears to be that it is cut off from its surroundings by dense traffic. In fact, this is only a part of the story. Simply removing the traffic would not in itself lead to significant improvements in pedestrian use. Space Syntax analysis of Trafalgar Square shows that - while the effects of traffic are important - they are not nearly as important as the influence of design.

Recent research has shown, and experience confirmed, that design can make the difference between well and poorly used urban spaces, and that design means first and foremost spatial design. Merely adding landscaping and facilities to poorly designed spaces will not make those spaces work. Good spatial design involves three key elements:

a. simple, direct routes for pedestrian movement which pass through the middle of the space and not just around its edges

b. positions within the space from which people can see out in several directions, and therefore understand the way in which the square fits into its wider urban context

c. facilities for eating, drinking or resting which are located close to - but not in the way of - the main pedestrian movement routes.

Our analysis shows that each of these elements is missing from the current design of Trafalgar Square. Instead, the current design of the space is directly responsible for the uneven pattern of use which we have observed. In particular:

a. detailed analysis of the visual 'fields' available from Trafalgar Square shows that the views available from the geometric centre of the Square (Figure 2) are very constricted, and nowhere near as strategic as those from the King Charles traffic island (Figure 3). This is why visitors to London gravitate towards the traffic island - dashing across the road with camera and guidebook in hand - in order to gain their bearings and take photographs:

Figure 2 Visual Field from Geometric Centre of Trafalgar Square

Figure 3 Visual Field from King Charles Traffic Island

b. the existing stairs in the north-west and north-east corners of the Square inhibit the kind of criss-crossing movement through the body of the space which other studies have shown to be an essential characteristic of well-used squares. As a result, Londoners moving from one corner of Trafalgar Square to the other find it easier to walk around the edges of the space than to cross diagonally.

Computer modelling of the spatial layout of the Square allows the precise relationship between spatial design and pedestrian activity to be measured. In Figure 4, the network of pedestrian routes in and around Trafalgar Square has been analysed using Space Syntax software:

Figure 4 Space Syntax Computer Model of Trafalgar Square EXISTING

The software calculates the relative accessibility of each spatial link in the network and represents the most accessible routes as red lines, then orange, yellow and green, to the least accessible lines which are blue. Accessibility is measured by calculating shortest journey routes between each link and all of the others in the network (defining 'shortest' in terms of fewest changes of direction).

Visual and statistical comparison between the Space Syntax analysis of accessibility and the actual pattern of pedestrian movement in Trafalgar Square shows a high degree of correspondence. In fact, the computer model successfully accounts for approximately three-quarters of the actual movement pattern (Figure 5), doing so even before we consider the effects of other environmental variables such as local land uses, transport facilities, building heights, vehicle movements and population densities:

Figure 5 Correspondence Between Computer Forecast and Actual Movement Rates

In this way, Space Syntax analysis provides the design team with a powerful tool for understanding the current pattern of pedestrian activity in Trafalgar Square, and demonstrating how this pattern is directly related to spatial design. Having understood current activity, the method can then be used as a design tool, by simulating design changes and evaluating the effects of these in terms of pedestrian activity.

Our experience from the World Squares for All project shows that Space Syntax analysis is also a design generator, highlighting areas which are either problematic (such as the change in level between the upper and lower parts of the Square) or which offer significant design potential (such as the area to the south of the Square around the statue of King Charles). When the spatial characteristics of an area have been pinned down, ideas for solutions begin to emerge in a process we term "evidence based design".

From Research to Design: Re-engineering the Square

The findings of the Space Syntax analysis have generated a number of key redesign ideas for Trafalgar Square. These have been tabled within the team and evaluated alongside others over the course of the project. Some of these are illustrated in Figure 6:

Figure 6 Proposed Redesign of Trafalgar Square

The redesign proposals include:

a. the southward extension of the Square and creation of new, direct pedestrian crossings to the north-west corner of Whitehall and the north side of Northumberland avenue. The main effects/benefits of this will be:

b. to expand the area of the Square which will be naturally used by visitors, decreasing the current congestion in the south-east corner;

c. to create an area in the Square with stunning all round views (in contrast to the current restricted views) from which visitors will take pictures both back into the Square and outwards into the surrounding urban area

d. to make important views available for Londoners and visitors alike to assist in orientation and movement. These include: Whitehall towards the Palace of Westminster; the Mall towards Buckingham Palace; Northumberland Street towards Hungerford Bridge and Cockspur Street towards St James'

e. to make the 'centre of London' a natural and safe destination for visitors to London, thus increasing the prestige, significance and reputation of the whole Square

f. opening up the north-east and north-west corner steps into the Square by the creation of two new flights of steps on diagonal alignments. The main effects/benefits of the 'diagonal' steps will be:

g. to facilitate movement across the Square for people living and working in the area, so that the Square becomes a natural part of their everyday journeys rather than the obstacle it is at present (currently the orientation of the steps is a key factor in eliminating natural movement through the Square), creating naturally used routes which are more pleasant, quicker and less hazardous than the current difficult routes around the outside

h. to facilitate movement by visitors to and from the southern parts of the Square, allowing movement into these areas to approach from different directions

i. improving the feel of the Square by creating background movement across the Square in several directions - this being crucial to the sense that a space is well and naturally used. This will help generate stationary use within the Square by Londoners as well as visitors

j. renovation of the upper level space (between the National Gallery and the existing Square) as an intrinsic part of Trafalgar Square.

The renovation of this space with its wonderful viewing potential will require the elimination of all everyday traffic (allowing occasional access for special visitors to the main entrance of the National Gallery) from the north side of the Square. However, this on its own, while essential, will not in itself realise the potential of the upper level space. This will also require the careful design of this space and its relation to the main body of the Square, since:

a. movement will continue to be primarily on the National Gallery side of this space, and more generous provision will therefore have to be made for this movement on the north side of the upper level space;

b. the south side of the upper level space will not (even with the corner steps) be a significant movement space, but will offer wonderful opportunities for stationary uses, for people wishing to relax and spend some time in the Square

c. a direct link between the lower level body of the Square and upper level part of the space via a new, centrally located stairway. At present the north, lower level part of the Square and the upper level space directly above it are the least used areas of the Square. While the corner steps will create diagonal movement across the Square, they will not by themselves animate either of these spaces. Nor will pedestrianisation of the upper north level alone animate the south side of the upper space. The central link between these two potentially poorly used spaces will therefore be critical to their mutual animation by:

d. providing a direct route into the lower level body of the Square from the National Gallery via the least used part of Trafalgar Square. Visitors to the Gallery will use this stair whereas they would not necessarily go into the Square if they had to use the corner steps. These steps will create a more localised link which will allow 'drift' from one space to the other, as well as providing a convenient route for people going directly to and from the Gallery

e. creating a natural east-west division in the upper level space, with more Londoner-focused facilities provided on the west side upper level space (where people working in the area would naturally stop) and more popular facilities on the east side of the upper level space (where there will be a higher and more mixed local movement population)

f. and, in general, the creation of new, well used diagonal routes across the Square for Londoners which are more pleasant, less time consuming and less hazardous that the current tortuous routes around the edge of Square.

Each of these design characteristics has emerged following numerous 'runs' of the pedestrian computer model. Since processing times are very short (a matter of seconds) it has been possible to use the computer as a sketchpad for testing, rejecting and refining design ideas. Analysis of the redesign proposals indicates the extent to which pedestrian linkages in and around the Square might be considerably improved (Figure 7).

Figure 7 Space Syntax Computer Model of Trafalgar Square PROPOSED

The Space Syntax model shows a significant increase in overall levels of pedestrian accessibility. In particular, new diagonal routes can be seen passing from one corner of the space to the other, making use of the new corner stairs and bringing a significantly greater degree of pedestrian activity to the heart of the space than exists at present.


Space Syntax techniques have been used by the World Squares team to generate and evaluate a range of design proposals throughout the Study Area. In each case the needs of pedestrians have been carefully evaluated through detailed observations of existing activity and spatial modelling of design possibilities. In this way a masterplan for the area has been developed which is firmly founded on the results of robust, evidence based techniques.