Resident Risk in Maidstone Borough 2013 by Agilysis

Resident Risk In Maidstone Borough

WELCOME Welcome to the SIGNPOST SERIES , a suite of reports to support professionals working in Road Safety. Designed by Road Safety Analysis, these profiles provide an authoritative overview of performance that can assist in directing investment and effort to reduce casualties on the roads. For more information on other services offered by Road Safety Analysis, please visit www.roadsafetyanalysis.co.uk

Contents Welcome .................................................................................................................................................................. 2 Introduction ............................................................................................................................................................. 3 Quality of postcode data...................................................................................................................................... 3 Overview of Maidstone Borough ............................................................................................................................. 4 Overall resident risk ................................................................................................................................................. 4 Resident casualties of any severity ...................................................................................................................... 4 Resident killed or seriously injured (KSI) casualties ............................................................................................. 4 Progress in reducing resident risk ........................................................................................................................ 4 Resident risk by age group ....................................................................................................................................... 6 Resident child casualties ...................................................................................................................................... 6 Resident young adult casualties .......................................................................................................................... 6 Resident adult casualties ..................................................................................................................................... 6 Resident senior casualties.................................................................................................................................... 7 Resident risk for vulnerable road user groups ......................................................................................................... 8 Resident pedestrian casualties ............................................................................................................................ 8 Resident pedal cycle user casualties .................................................................................................................... 8 Resident motorcycle user casualties.................................................................................................................... 8 Motorcycle user casualties .............................................................................................................................. 8 Moped user casualties ..................................................................................................................................... 9 Resident young adult drivers ............................................................................................................................... 9 Appendix ................................................................................................................................................................ 10 Data sources....................................................................................................................................................... 10 Correction for missing postcode data ................................................................................................................ 10

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SIGNPOSTS

2013: RISK MAIDSTONE

IN ROAD SAFETY

RESIDENT CASUALTIES FOR

BOROUGH By Road Safety Analysis

INTRODUCTION The SIGNPOST SERIES are road safety profile documents which provide comprehensive insight into risk faced by local communities. Each profile examines either road risk on the network of a specific highway authority, or risk experienced by the residents of a particular local authority district area. This profile examines risk to residents in Maidstone Borough. All crash, vehicle, driver and casualty information in this document is derived from national STATS19 data for a six year period from 2007 to 2012. Residency of people involved in crashes can be derived from postcodes collected by police forces. The figures in this profile refer to casualties and drivers with postcodes in Maidstone Borough. This dataset, including full residency information, is available to the road safety community for detailed analysis in MAST Online. A less complete version of STATS19, which does not include residency information, can be downloaded as a raw dataset from HM Government's transparency website at data.gov.uk. Residency profiles assess risk on the basis of where people live rather than where they crash because residency is the most appropriate basis for measuring socio-demographic factors which influence road risk. Since about two out of every five crash victims are injured outside the district where they live, it is inadvisable simply to equate 'crashes on local roads' with 'risk to local population'. Factors such as commuting and through traffic travelling long distances can result in substantial differences between the type of risk encountered on a road network and the risk to people who live in communities nearby.

Quality of postcode data While collection of postcode data as part of STATS19 is substantial and improving, it is not absolutely complete. Nationally, about 20% of casualties and drivers have no postcode reported in police STATS19 returns. Considerable local variation between police forces is also found, with missing postcode rates ranging from as low as 5% in some areas to as much as 43% in others. However, casualties and drivers with missing postcodes have been included in this analysis. For these cases, the most likely distribution of residency has been estimated using an algorithm specially constructed by RSA. The technique used is explained in detail in an appendix to this report. It is necessary to adjust casualty figures in this way for three reasons. Firstly, it ensures that the overall casualty total when reporting resident risk agrees exactly with figures published by the Department for Transport in REPORTED ROAD CASUALTIES GREAT BRITAIN. Secondly, it improves relevance and reliability by providing the largest possible sample size. Thirdly, it minimises distortion of casualty rates due to local postcode reporting practices: if no adjustment was made, then residents in police forces which report relatively few postcodes would seem to experience deceptively low risk, while conversely residents in forces which report almost all postcodes would appear to face misleadingly high risk.

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OVERVIEW OF MAIDSTONE BOROUGH The English District council area of Maidstone Borough (ONS code E07000110) covers an area of around 151.3 square miles. It had a total population of 155,143 approx based on 2011 mid-year estimates, placing it in the 6th decile in terms of population density (220th out of 379 districts).

OVERALL RESIDENT RISK This section calculates risk based on all residents of Maidstone Borough who suffered any injury in reported crashes anywhere on Britain's roads over the six year period 2007 to 2012, regardless of age or road user type. It is likely that additional unreported casualties occurred, but no estimate of these can be included in this report. Maidstone Borough's overall risk and progress in comparison to other areas is illustrated in Chart 3.

Resident casualties of any severity On average, approximately 663 casualties per year are reported among residents of Maidstone Borough. These figures include slight injuries such as minor cuts, bruises, shock and whiplash. This equates to an injury rate of one in every 234 residents each year. In comparison, the national rate is one in every 281 British residents each year. Consequently, Maidstone Borough's national injury risk index is 120, where a value of 100 represents the national rate. This means that injury risk experienced by residents of Maidstone Borough is 20% higher than the national average. Maidstone Borough has a national injury risk ranking of 46th (where first place indicates the highest risk), placing it in the 2nd decile of injury risk across 379 districts in Britain.

Resident killed or seriously injured (KSI) casualties On average, approximately 78 casualties per year are reported as killed or seriously injured among residents of Maidstone Borough. This figure includes an average of 7 casualties per year who were killed, but excludes all slight injuries. This equates to a KSI rate of one in every 2,002 residents each year. In comparison, the national KSI rate is one in every 2,294 British residents each year. A comparison of KSI to overall risk is illustrated in Chart 1. Consequently, Maidstone Borough's national KSI risk index is 115, where a value of 100 represents the national rate. This means that KSI risk experienced by residents of Maidstone Borough is 15% higher than the national average. Maidstone Borough has a national KSI risk ranking of 113th (where first place indicates the highest risk), placing it in the 3rd decile of KSI risk across 379 districts in Britain.

Progress in reducing resident risk These statistics measure the change in road casualty risk over time for residents of Maidstone Borough. The local trend is established by comparing a baseline (2007 to 2009) to the most recent information available (2010 to 2012). Progress is assessed by evaluating this trend relative to nationwide change over the same period. A comparison of recent progress to overall risk is illustrated in Chart 1. The average number of resident casualties has changed by -80 casualties per year over three years. This includes a change in resident KSI casualties of -17 casualties per year over three years. Maidstone Borough has an injury progress index of 102, where a value of 100 represents the national rate of progress and higher values indicate less progress. The corresponding KSI progress index is 94. This means that progress in improving the injury risk experienced by residents of Maidstone Borough is 2% slower than the national rate over the last three years, while progress in improving KSI risk is 6% faster than the national rate.

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Maidstone Borough's national injury progress ranking is 238th (where first place indicates the best progress), placing it in the 7th decile of progress across 379 districts in Britain. The corresponding KSI progress ranking is 127th, placing Maidstone Borough in the 4th decile of progress.

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RESIDENT RISK BY AGE GROUP This section calculates risk for different age groups of Maidstone Borough's residents who suffered injury in reported crashes anywhere on Britain's roads over the six year period 2007 to 2012, regardless of road user type. It is likely that additional unreported casualties occurred. Progress rankings have been calculated for each group using the same technique as that used for progress in risk to all residents. A comparison of risk for individual age groups to overall risk is illustrated in Chart 1.

Resident child casualties Maidstone Borough's child population based on 2011 mid-year estimates is 29,667 approx. For the purposes of this analysis, children are all persons under the age of 16. On average, approximately 65 casualties per year are reported among children resident in Maidstone Borough. This equates to a rate of one in every 455 resident chidren each year. In comparison, the national child injury rate is one in every 562 British resident children each year. Consequently, Maidstone Borough's national child injury risk index is 123, where a value of 100 represents the national rate. This means that injury risk experienced by child residents of Maidstone Borough is 23% higher than the national average for the same age group. Maidstone Borough has a national child injury risk ranking of 67th (where first place indicates the highest risk), placing it in the 2nd decile of child injury risk across 379 districts in Britain. The average number of child resident casualties has changed by -3 casualties per year over three years. Maidstone Borough has a child injury progress index of 111, where a value of 100 represents the national rate of progress and higher values indicate less progress. This means that progress in improving the injury risk experienced by children resident in Maidstone Borough is 11% slower than the national rate over the last three years. Maidstone Borough's national child injury progress ranking is 285th (where first place indicates the best progress), placing it in the 8th decile of progress across 379 districts in Britain.

Resident young adult casualties Maidstone Borough's young adult population based on 2011 mid-year estimates is 16,018 approx. For the purposes of this analysis, young adults are all persons aged between 16 and 24 inclusive. On average, approximately 184 casualties per year are reported among young adult residents of Maidstone Borough. This equates to a rate of one in every 87 young adult residents each year. In comparison, the national young adult injury rate is one in every 132 British young adult residents each year. Consequently, Maidstone Borough's national young adult injury risk index is 152, where a value of 100 represents the national rate. This means that injury risk experienced by young adult residents of Maidstone Borough is 52% higher than the national average for the same age group. Maidstone Borough has a national young adult injury risk ranking of 41st (where first place indicates the highest risk), placing it in the 2nd decile of young adult injury risk across 379 districts in Britain. The average number of young adult resident casualties has changed by -29 casualties per year over three years. Maidstone Borough has a young adult injury progress index of 105, where a value of 100 represents the national rate of progress and higher values indicate less progress. This means that progress in improving the injury risk experienced by young adult residents of Maidstone Borough is 5% slower than the national rate over the last three years. Maidstone Borough's national young adult injury progress ranking is 244th (where first place indicates the best progress), placing it in the 7th decile of progress across 379 districts in Britain.

Resident adult casualties This section analyses the road safety profile of adults aged between 25 and 59 inclusive. Maidstone Borough's population in this age group is 72,743 approx, based on 2011 mid-year estimates. On average, approximately 329 casualties per year are reported among adult residents of Maidstone Borough. This equates to a rate of 6|Page

one in every 221 adult residents each year. In comparison, the national adult injury rate is one in every 252 British adult residents each year. Consequently, Maidstone Borough's national adult injury risk index is 114, where a value of 100 represents the national rate. This means that injury risk experienced by adult residents of Maidstone Borough is 14% higher than the national average for the same age group. Maidstone Borough has a national adult injury risk ranking of 72nd (where first place indicates the highest risk), placing it in the 2nd decile of adult injury risk across 379 districts in Britain. The average number of adult resident casualties has changed by -41 casualties per year over three years. Maidstone Borough has an adult injury progress index of 99, where a value of 100 represents the national rate of progress and higher values indicate less progress. This means that progress in improving the injury risk experienced by adult residents of Maidstone Borough is 1% faster than the national rate over the last three years. Maidstone Borough's national adult injury progress ranking is 201st (where first place indicates the best progress), placing it in the 6th decile of progress across 379 districts in Britain.

Resident senior casualties Maidstone Borough's senior population based on 2011 mid-year estimates is 36,715 approx. For the purposes of this analysis, seniors are all persons aged 60 or more. On average, approximately 69 casualties per year are reported among senior residents of Maidstone Borough. This equates to a rate of one in every 531 senior residents each year. In comparison, the national senior injury rate is one in every 571 British senior residents each year. Consequently, Maidstone Borough's national senior injury risk index is 108, where a value of 100 represents the national rate. This means that injury risk experienced by senior residents of Maidstone Borough is 8% higher than the national average for the same age group. Maidstone Borough has a national senior injury risk ranking of 118th (where first place indicates the highest risk), placing it in the 4th decile of senior injury risk across 379 districts in Britain. The average number of senior resident casualties has changed by -10 casualties per year over three years. Maidstone Borough has a senior injury progress index of 91, where a value of 100 represents the national rate of progress and higher values indicate less progress. This means that progress in improving the injury risk experienced by senior residents of Maidstone Borough is 9% faster than the national rate over the last three years. Maidstone Borough's national senior injury progress ranking is 97th (where first place indicates the best progress), placing it in the 3rd decile of progress across 379 districts in Britain.

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RESIDENT RISK FOR VULNERABLE ROAD USER GROUPS This section assesses risk among those Maidstone Borough residents who may be among the most vulnerable to injury or crash involvement. Like other sections of this report which address resident risk, the scope of this section covers all reported crashes anywhere on Britain's roads over the six year period 2007 to 2012. It is likely that additional unreported crashes involving Maidstone Borough residents occurred. Progress indices and rankings are only available in categories where sample sizes are generally large enough for results to be meaningful. A comparison of risk between different road user groups is illustrated in Chart 2.

Resident pedestrian casualties On average, approximately 79 casualties per year are reported as pedestrians resident in Maidstone Borough. This equates to a rate of one in every 1,972 residents each year. In comparison, the national pedestrian injury rate is one in every 2,262 British residents each year. Consequently, Maidstone Borough's pedestrian injury risk index is 115, where a value of 100 represents the national rate. This means that pedestrian injury risk experienced by residents of Maidstone Borough is 15% higher than the national average. Maidstone Borough has a national pedestrian injury risk ranking of 78th (where first place indicates the highest risk), placing it in the 3rd decile of pedestrian injury risk across 379 districts in Britain. The average number of pedestrian resident casualties has changed by +4 casualties per year over three years. Maidstone Borough has a pedestrian injury progress index of 115, where a value of 100 represents the national rate of progress and higher values indicate less progress. This means that progress in improving the pedestrian injury risk experienced by residents of Maidstone Borough is 15% slower than the national rate over the last three years. Maidstone Borough's national pedestrian injury progress ranking is 315th (where first place indicates the best progress), placing it in the 9th decile of progress across 379 districts in Britain. A comparison of pedestrian progress to overall pedestrian risk is illustrated in Chart 2.

Resident pedal cycle user casualties On average, approximately 28 casualties per year are reported as pedal cycle users resident in Maidstone Borough. This equates to a rate of one in every 5,574 residents each year. In comparison, the national cyclist injury rate is one in every 3,505 British residents each year. These figures include both pedal cycle riders and pillion passengers reported as injured in crashes. Consequently, Maidstone Borough's cyclist injury risk index is 63, where a value of 100 represents the national rate. This means that cyclist injury risk experienced by residents of Maidstone Borough is 37% lower than the national average. Maidstone Borough has a national cyclist injury risk ranking of 283rd (where first place indicates the highest risk), placing it in the 8th decile of cyclist injury risk across 379 districts in Britain.

Resident motorcycle user casualties In order to improve insight into local issues and priorities, motorcycle user risk has been split into two categories for separate analysis. For the purpose of this report, motorcycles include all powered two wheeled vehicles with a reported engine capacity of 50 cc or over. Mopeds are powered two wheeled vehicles with a reported engine capacity under 50 cc. All figures include both riders and pillion passengers reported as injured in crashes. Motorcycle user casualties On average, approximately 61 casualties per year are reported as motorcycle users resident in Maidstone Borough. This equates to a rate of one in every 2,530 residents each year. In comparison, the national MC user injury rate is one in every 3,564 British residents each year. Consequently, Maidstone Borough's MC user injury risk index is 141, where a value of 100 represents the national rate. This means that MC user injury risk experienced by residents of Maidstone Borough is 41% higher than the national average. Maidstone Borough 8|Page

has a national MC user injury risk ranking of 47th (where first place indicates the highest risk), placing it in the 2nd decile of MC user injury risk across 379 districts in Britain. Moped user casualties On average, approximately 12 casualties per year are reported as moped users resident in Maidstone Borough. This equates to a rate of one in every 12,929 residents each year. In comparison, the national moped user injury rate is one in every 17,919 British residents each year. Consequently, Maidstone Borough's moped user injury risk index is 139, where a value of 100 represents the national rate. This means that moped user injury risk experienced by residents of Maidstone Borough is 39% higher than the national average. Maidstone Borough has a national moped user injury risk ranking of 101st (where first place indicates the highest risk), placing it in the 3rd decile of moped user injury risk across 379 districts in Britain.

Resident young adult drivers Unlike other assessments of resident risk in this profile, this section is not restricted to examining casualties of reported crashes. Instead, it focuses on all drivers involved in crashes, regardless of personal injury. This approach is used to scrutinise the exposure of younger drivers to risk. All analysis within this section excludes riders of pedal cycles, motorcycles and mopeds, since risk for these road user groups has been considered separately. For the purposes of this analysis, young adults are all persons aged between 17 and 24 inclusive. This has been updated from last year, where 16 year olds were included, due to the release of population by single age data at local authority district level which allows us to omit 16 year olds. Maidstone Borough's young driver (17 to 24) population based on 2011 mid-year estimates is 14,047 approx. On average, approximately 160 drivers per year among young adults resident in Maidstone Borough are reported as being involved in an injury crash. This equates to a rate of one in every 88 young adult residents each year. In comparison, the national young adult driver involvement rate is one in every 146 British young adult residents each year. In order to place young driver involvement into perspective, it is useful to compare this rate to the equivalent for all drivers of any age. The involvement rate for all drivers resident in Maidstone Borough is one in every 150 residents aged 16+ each year, compared to the national rate of one in every 196 British residents aged 16+ each year. Maidstone Borough's young adult driver involvement risk index is 166, where a value of 100 represents the national rate. This means that the driver involvement risk experienced by young adult residents of Maidstone Borough is 66% higher than the national average. Maidstone Borough has a national young adult driver involvement risk ranking of 35th (where first place indicates the highest risk), placing it in the 1st decile of young adult driver involvement risk across 379 districts in Britain. The average number of young adult drivers involved in crashes has changed by -13 drivers per year over three years. Maidstone Borough has a young adult driver involvement progress index of 117, where a value of 100 represents the national rate of progress and higher values indicate less progress. This means that progress in improving the young adult driver involvement risk experienced by residents of Maidstone Borough is 17% slower than the national rate over the last three years. Maidstone Borough's national young adult driver involvement progress ranking is 348th (where first place indicates the best progress), placing it in the 10th decile of progress across 379 districts in Britain. A comparison of young driver progress to overall young driver risk is illustrated in Chart 2.

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APPENDIX Data sources Reported road casualties by residency: MAST Online http://www.roadsafetyanalysis.org/mast-online/ Subset of raw STATS19 dataset released by HM Government: Data.gov.uk http://data.gov.uk/dataset/road-accidents-safety-data Population and area in England and Wales: Office for National Statistics http://www.ons.gov.uk/ons/taxonomy/index.html?nscl=Population+Estimates Population and area in Scotland: General Register Office for Scotland http://www.gro-scotland.gov.uk/statistics/theme/population/estimates/mid-year/index.html

Correction for missing postcode data Because SIGNPOST SERIES profiles calculate resident risk by population, it is necessary to correct for regional variation in postcode reporting. Otherwise, areas in force areas which are poor at reporting postcodes would have lower resident casualty figures and therefore better risk rates than they should, but forces which are meticulous at reporting would be penalised. This would be inaccurate, misleading and unfair. It is also important to ensure that the total number of casualties attributed to every authority in the report added up exactly to the overall total, so local risk rates can be compared directly to each other and meaningfully to the national rate. The procedure below describes in detail how adjusted authority resident casualty figures are derived. Each step is illustrated by an example, involving two fictional entities: a police force called Southshire Constabulary, and the unitary council area of Northtown Borough Council which is elsewhere in the country, far from Southshire. 1. The following data was extracted from MAST Online: a. Casualties with unknown postcodes reported by each force in Britain; Southshire Constabulary had 8,381 casualties where Casualty Home was 'Unknown' b. Total casualties reported by each force in Britain, from which the number of postcodes successfully reported by each force was calculated; Southshire Constabulary reported 47,400 casualties altogether, so they reported 39,019 casualty postcodes (47,400 minus 8,381) c. All casualties categorised by authority area of residency according to reported postcode, broken down by the force area in which the crash occurred. There were a total of 4,882 casualties reported across Britain with a Northtown postcode, of which 183 were reported as injured in a crash in the Southshire Constabulary force area 2. For each home authority, the proportion of residents known to have crashed in each police force area was calculated. 3.75% of Northtown resident casualties sustained their injury in Southshire (183 divided by 4,882) 3. For each combination of home authority and police force area of crash, the proportion of all casualties in that police force area who were known to live in the authority in question was calculated. 0.47% of all postcodes reported by Southshire Constabulary are in Northtown, calculated as 183 divided by 39,019 4. The number of unknown casualties reported by each force from each authority was calculated, assuming that unknown casualties follow the same distribution as the known ones. About 39.3 of Southshire's unknown casualties were assigned to Northtown (0.47% of 8,381) 10 | P a g e

5. The adjusted casualty total for each combination of home authority and police force area of crash was calculated. About 222.3 Northtown residents were included in the total casualties reported by Southshire Constabulary , 183 with known postcodes plus an assumed 39.3 from casualties with unknown postcodes 6. These calculations were checked by adding up the adjusted totals for all authorities. The result is exactly equivalent to the actual casualty total as published in REPORTED ROAD CASUALTIES GREAT BRITAIN and MAST Online. 7. Exactly the same process was repeated for casualty and driver figures for each relevant each road user group, to derive a distinct set of correction factors for each. Southshire Constabulary reported 3,924 child casualties in the force area including 919 missing postcodes, and 5 Northtown resident children were known to have suffered injury in Southshire out of a total of 291 known Northtown resident child casualties altogether This algorithm makes certain assumptions, which may affect the results to some degree. These assumptions and their possible consequences are made explicit below. 

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Missing casualty postcodes arise mainly because of internal reporting practices within police forces, so all reporting of postcodes in STATS19 by any given force is probably affected to about the same extent regardless of where each individual casualty resides. However, if reporting officers were significantly more likely to report recognised local postcodes than less familiar ones, then this calculation could slightly overestimate resident casualty figures for authorities with unusually high concentrations of local casualties (often more rural or remote areas), and conversely slightly underestimate for authorities with high concentrations of non resident casualties (often those in urban areas or with long stretches of trunk routes). The reporting of foreign resident casualties in STATS19 is unreliable. In principle, foreign residents should be reported with the special code'2' in place of the postcode, but in practice only 2,414 instances of this were returned between 2007 and 2012. If taken at face value this would mean that only 0.22% of all casualties on Britain's roads (1 casualty in every 455) were foreign residents, and that they account for only 2.7% of all casualties reported without a postcode. However, anecdotal evidence and common sense suggest that there is widespread and significant under-reporting of foreign resident casualties. There are significant inconsistencies between forces in recording foreign residents. For instance Kent Police reported only six casualty postcodes with '2' over the entire six year period while Northern Police, which lies hundreds of miles distant from most major points of entry to Britain and is over five times smaller in terms of population, reported 195 in the same period. Since there is insufficient data to represent foreign resident casualties in a robust manner, the only consistent course of action is to distribute all casualties without postcodes as if they were British residents, including the relatively few records which contain the official foreign resident STATS19 code. This assumption will increase all adjusted resident casualty figures to a small but unquantifiable extent. It may also disproportionately affect a few authorities where an unusually high number of casualties reported in the local force area could in fact be foreign residents (often those containing heavily used points of entry to Britain), or where the code '2' is in fact widely reported. Postcodes in Northern Ireland are reported as 'Unknown', because casualty figures on Northern Ireland's roads do not fall in the scope of STATS19 reporting and therefore are not yet included in MAST. Consequently, the considerations explained above concerning authorities with unusually high foreign resident casualty rates may also apply to any authorities where an unusually high number of casualties reported in the local force area could in fact be residents of Northern Ireland.

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200

150

120

115

123

152

114

108

100

All Casualties 0

KSI Casualties

Child Casualties

Young Adult Casualties

Adult Casualties

Senior Casualties 0

[Dashed Lines] Progress Index - last three years (High Index = Less Progress)

[Solid Bars] National Risk Index (High Index = Greater Risk)

Chart 1 - Maidstone Borough Resident Risk and Progress Indices - Age Bands (2007 2012)

200

150

115

166

131

141

139

100

Pedestrian Casualties 0

Young Adult Drivers

Drivers

Pedal Cycle Casualties

MC Casualties

Moped Casualties 0

[Dashed Lines] Progress Index - last three years (High Index = Less Progress)

[Solid Lines] National Risk (High Index = Greater Risk)

Chart 2 - Maidstone Borough Resident Risk and Progress Indices - Road User Type (2007 - 2012)

Chart 3 - Local Authority District Resident Risk: Performance and Progress (2007 - 2012) 140

Low risk, less improvement

High risk, less improvement

130

120

Recent Progress Index

110

100

Maidstone Borough 80

Low risk, more improvement

High risk, more improvement

60 20

100

All Resident Casualties Index

120

140

160