How surveys are carried out
A standardised roadside method, stated on the report so the findings can be read in context.
KerbSight surveys are observational. A trained surveyor visits the location, stands in a safe position off the carriageway, and records what passes. The surveyor is not there to stop vehicles or to direct traffic. The position is chosen so that the observations can be made clearly, without becoming a distraction to drivers.
What is agreed beforehand
Before the visit we agree the road, the point to be surveyed, the question the survey needs to answer, and the duration. A short session can be the right choice when the concern is a particular hour. A longer session is the right choice when you need the shape of the whole day. The agreement is what the report later describes. It is not adjusted afterwards to suit a preferred result.
What is recorded on site
- The time of each observation
- Speed, for a speed survey, in miles per hour
- Direction
- Vehicle type, in broad classes
- For a pedestrian survey, the movement rather than a vehicle speed
The survey also notes the posted limit where there is one, the weather, the road conditions, and anything about the session that a reader should know, such as roadworks or an obstruction. Those notes are part of the record, not a footnote to be dropped if they are inconvenient.
Analysis
The figures are produced after the visit, from the observations, not as a judgement made at the kerb. For a speed survey that includes the distribution, the mean, the 85th percentile and the share of vehicles at or below the posted limit, with a directional split. The report says which method version was used, so a later survey can be compared with it.
More on how those figures are presented is under reports and data. The sample report shows the layout with demonstration data only.
What this method is not
It is not covert enforcement, and it is not a community speed watch. KerbSight does not represent the police. Measurements are independent observations. Where a highway authority or a police force needs evidence for its own process, that is a matter for them. A KerbSight report can inform a conversation. It does not replace their procedures.