The Scottish Government

Development Department Research Programme Research Findings No 68: 1999

Community Impact of Traffic Calming Schemes

Ross Silcock Limited/Social Research Associates

Main Findings

• Residents' perception of speed reduction appears to be accurately reflected by objective measurement.
• Where speeds had been noticeably reduced by traffic calming, this was translated into improved perceptions of safety for cyclists and pedestrians and led to children being allowed to play out, walk to school and cycle more. Significant numbers of adults also walked and cycled more in these areas.
• Variations in local culture and tastes impact on judgements about appropriate designs for traffic calming. Some areas, for example, adapt more readily than others to control behaviour by design features, whilst others have a tradition of, and more confidence in, enforcement via police or speed cameras.
• The initial objectives of the scheme were often unclear to residents and feedback to residents on the results of calming was almost entirely lacking.
• There appears to be strong correlation between public approval of a scheme and judgements about the extent and quality of public consultation which took place.
• In those schemes where the majority felt that consultation had been adequate the local Community Council had been involved, and there was a feeling that issues had been explained.
• Using leaflets through the letterbox, or a public exhibition, were felt to be inadequate consultation mechanisms. In these cases the technical information seemed to be presented in a way that was difficult to understand, and there was also a sense that the decisions had all been made.
• Inadequate consultation was linked to more support for removing the scheme although in general only a small minority of residents wanted measures removed entirely.
• In some cases there was a feeling that the traffic calming had achieved its aims and might now be reduced in scope.

Background

In 1987, following a wide ranging review of road safety policy, the government set a national target to reduce casualties by one third by the year 2000. As a result, many local initiatives have been implemented to improve road safety including traffic calmed schemes. The effectiveness of these schemes can be measured in terms of reductions in accidents and vehicle speeds, but little is known about the schemes effect on the local community. The Scottish Office therefore commissioned research into the community impact of several traffic calmed areas in Scotland.

The main aim was to investigate the social and environmental effects of different types of traffic calming on the local community. The research sought to measure changes in travel habits and street use, examine attitudes to the scheme, and identify what makes a scheme successful in terms of community impact and acceptance.

Methodology

The work consisted of three main elements:

• a literature search;
• identification of recently implemented schemes with appropriate before and after data; and
• structured interviews of local residents.

The literature search covered documents published from 1990 to October 1997. It indicated that the few studies that examined public attitudes to traffic calming mainly concentrated on perceptions of specific features and on public consultation. Some studies have shown that there is often conflicting evidence with results of 'objective' measurement used by engineers and planners contrasting with the perceptions of local people.

Very little work appeared to have been carried out with respect to a number of factors such as changes in people's behaviour, activities and travel patterns resulting from changes in the street function. These are some of the issues that this study sought to address.

Schemes were selected to represent typical traffic calming schemes that have been implemented in Scotland. The scheme selection criteria, were:

It was important that the schemes should have been implemented within the time period January 1996 and December 1997. This was to allow for the effects of a scheme to stabilise but not be so old that residents would not remember what the area was like beforehand.

Five schemes were selected from residential area-wide schemes. These were:

Five schemes were also selected from a traffic calming inventory of the trunk road network. These were:

The information gleaned from the literature search was then used to devise suitable questionnaires for members of the population in each of the areas identified. The surveys were carried out on a target sample of 150 residents in each area over a three day period during July to September 1998. This sample was split into various interest groups. Interviews were carried out by both group discussions and individual interviews. In some cases, where communities were small, the target sample was not achieved. However, a representative cross section of the community was interviewed.

In addition, on the trunk road schemes, drivers were interviewed at locations where they would have passed through the schemes. The target sample for drivers was 50 per scheme.

Table 1: Quantified Changes in Safety

1 Depending on the completion date of the individual schemes the after accident period varies between 10 and 28 months. The before period is at least 3 years, based on data supplied by The Scottish Office (trunk roads) and local authorities.
2 in 2 hours peak
3 Annual Average Daily Traffic
4 in 1 hour pm
5 This covers 5 years of before accident data; all others cover 3 years before.
6 Scheme report information from South Ayrshire covering 3 years to December 96 and June to October 97.

Results

The amount of social survey information was variable and a full cross scheme comparison was not possible. However, it is possible to draw useful lessons and insights from the information that was available.

Road Safety

Accident data was made available for all schemes and covered the three years before implementation (except one scheme which covered five years) and a variable period after implementation. These two periods are not comparable and the latter periods generally vary between 12 and 16 months. This has made statistical analysis of the change in accidents impossible. However most schemes show a decrease in both the number and severity of accidents (see Table 1).

Consultation

Local authority consultation appears to have been less effective than that for trunk roads. There appears to be a strong correlation between approval of a scheme and judgements about the extent and quality of public consultation which took place. This is to a large extent independent of actual amount of consultation (eg see Tollohill and Pather in Table 2 below). Inadequate consultation was linked to more support for removing the scheme completely, although in general only a small minority of residents wanted measures entirely removed. It appears that satisfaction level is related more to consultation method than type of measure implemented.

The results from the different schemes also show variations in local culture and tastes which impact on judgements about appropriate designs for traffic calming. Some areas, for example, adapt more readily than others to control of behaviour by design features, whilst others have a tradition and more confidence in enforcement via police or speed cameras.

Table 2: Ratings for Consultation compared to Ratings for Scheme

Table 3: Percentage of Responses Rating Individual Scheme Elements as Effective

Table 4 shows how in most schemes residents allowed their children to play out, walk or cycle more. In addition significant proportions of adults also walked and cycled more as a result of traffic calming.

Table 4: Percentage of Responses (of those with children) Allowing Children to Walk or Cycle more as Result of Scheme

Driver Surveys

In order to assess the views of passing motorists, additional surveys were carried out at 4 of the trunk road case study sites (Tarbet, Crianlarich, Thornhill and Ballantrae). It was considered important to assess whether drivers, who might not be part of the immediate community, had different perceptions of the impact of the measures from the local community itself. Drivers tended to be more positive about the changes than residents; tended to appreciate the effect of a reduction in speed more than residents; felt that safety had improved for all road user groups; and that measures were more beneficial to non-motorised users than did the residents themselves. Interestingly, although numbers were small, drivers who lived more than 10 miles away were more likely to think the scheme had made things better than drivers who lived locally.

Lack of Information About Effects

Perceptions of the efficiency of traffic calming measures were influenced by knowledge of their effects. Since they had been installed, very few communities in the study had received information about the impact of the traffic calming scheme on such aspects as accident rates, speeding, changes in modal choice, pollution and even crime rates. Even where there had been extensive consultation beforehand, there was little or no feedback afterwards. This appeared to affect people's motivation, especially when the negative impacts of the traffic calmed scheme (eg intrusive humps) were more apparent than the benefits (eg reduction in speeding or accidents).

Conclusions and Recommendations

The fact that traffic calming is generally popular has masked the considerable opportunities which exist to improve what is provided and at the same time render the investment more effective in terms both of accident reduction and the encouragement of walking and cycling. The research has revealed the key role of public consultation in influencing the acceptance and impact of traffic calming schemes by the local community. There is no ideal framework for public consultation about traffic calming. Each scheme has to be treated individually taking into account all local circumstances. The main recommendations on good practice emerging from this research include:

• The purpose of the proposed scheme needs to be clearly communicated.
• Some education about the use and purpose of the measures should be communicated.
• The location of the measures and their appearance needs to be clearly explained.
• The extent to which the scheme can be modified needs to be made explicit.
• Data requirements and effective monitoring need to be established before design begins.
• Feedback and monitoring needs to be maintained throughout the design and implementation.
• Every effort should be taken to involve the local community in the design process.
• Community groups should be used where they exist.
• A comprehensive consultation plan throughout the scheme development and its first year of operation should be implemented.
• Consultation must not be limited to leaflet drops and exhibitions.