Article 4. Contributory factors to reported road accidents

Article 4. Contributory factors to reported road accidents

Summary

This article describes the scope and limitations of the information on contributory factors collected as part of the road accident reporting system and presents Scottish results from the seventh year of collection.

  • Driver/rider errors or reactions were reported in 66 per cent of all reported accidents with failed to look properly the most common type (involved in 32%).
  • Travelling too fast for the conditions or excessive speed was reported in 12% of all reported accidents and 26% of fatal accidents.
  • Pedestrian only factors were reported in 18% of fatal accidents whilst loss of control and failed to look properly were the most frequently reported driver/rider factors (involved in 47% and 21% of fatal accidents respectively).

Note that some percentages for Contributory Factor Categories (ie not individual factors) used in this article in the 2009 and 2010 publications included a small amount of double counting of accidents where more than one contributory factor is recorded in the same category. This included the speeding and driver error/reaction percentages. For example in some accidents both 'exceeding speed limit' and 'travelling to fast for conditions' will be recorded as a contributory factor by simply adding the percentages recorded for each factor in table M which results in some accidents being counted twice. Category totals in Table M and Table N of this publication remove double counting as do the figures for speeding reported in the text.

The impact on some percentages is small or not noticeable as it depends on the number of accidents where more than one factor is used within a category. The impact is greatest for fatal accident figures as fatal accidents have a higher number of contributory factors recorded per accident on average. The speed bullet above would have shown 12% and 32% previously ie 6% of fatal accidents have both contributory factors listed. For accidents of all severities the proportion of double counting is so small as to not be noticeable when the percentage is rounded.

1. Introduction

1.1 From 2005, all police forces across Great Britain reported contributory factors as part of the stats19 collection. These were developed to provide insight into why and how road accidents occur. Their aim is to help identify the key actions and failures that led directly to the actual impact: to aid investigation of how it might have been prevented. Care should always be taken when interpreting the factors as they:

  • reflect the reporting officer's opinion at the time of reporting the accident (or the opinion of a person whose duties include deciding which CFs should be recorded based on the officer's report).
  • are based on the information which was available at that time, so may not be the result of subsequent extensive investigation (indeed, subsequent enquiries could result in the reporting officer's opinion changing).

1.2 A reporting office attending the scene of a road accident may select up to 6 contributory factors (from a list of 77) to assign to that accident. Multiple factors may be listed against any participant or vehicles in the accident, (therefore percentages in the tables provided may not sum to 100).

1.3 Because of this, analysis of contributory factor information requires careful consideration; figures will differ depending on the focus of the analysis. Care should be taken when interpreting tables provided here which consider different aspects of the data (i.e. accidents, vehicles/participants, casualties and frequencies).

1.4 This article presents analysis from accidents in Scotland reported to the police in 2011, with the following background note describing the collection of the contributory factor system in more detail.

1.5 Note that most tables are by individual contributory factor so care needs to be taken when carrying out analysis. Adding together numbers for individual contributory factors will result in some double counting e.g. some accidents will have 'exceeding speed limit' and 'driving to fast for the conditions' recorded as a factor.

2. Accidents

Categories

2.2 Each of the 77 contributory factors fits into one of nine categories. Figure 11 shows the percentage of accidents reported to the police with associated contributory factors in each these categories.

  • Driver/rider error was the most frequently reported category for each type of severity of accident and was reported in 66 per cent of fatal accidents reported to the police).
  • Pedestrian contributory factors (where the factor has been attributed to an injured or uninjured pedestrian involved in the accident), were reported in 16 per cent of reported accidents , rising to 23 per cent of serious accidents.
  • Injudicious action (including travelling too fast for conditions, following too close or exceeding speed limit) was involved in 23 per cent of all reported accidents, increasing to 30 per cent of fatal accidents.
  • Road environment factors were reported in 19 per cent of reported accidents.

Figure 11: Contributory factor type: Reported accidents by severity, 2011

Figure 11: Contributory factor type: Reported accidents by severity, 2011

Factors

2.3 On average there were more than two contributory factors listed per reported accident with more factors recorded for fatal accidents and fewer for slight accidents. Table M shows the numbers (and percentages) of reported accidents in which each contributory factor was reported.

  • Failed to look properly was the most frequently reported contributory factor, involved in 32 per cent of all reported accidents. This was followed by loss of control (17%) and failed to judge other person's path/speed (15%). Slippery road (13%) and careless/reckless or in a hurry, poor turn/manoeuvre and pedestrian failed to look properly (all 11%) were also in the top five.
  • Travelling too fast for the conditions or excessive speed was reported in 12% of all reported accidents and 26% of fatal accidents.
  • For fatal accidents, loss of control was the most frequently reported driver/rider factor involved in 47% of accidents. Driver / Rider failed to look properly was reported in 21% and Travelling too fast for the conditions was involved in 19 per cent of fatal accidents.

2.4 Table M also shows how the incidence of some CFs varies with the severity of the accident. For example: loss of control is cited in 17% of all accidents for which CFs were recorded but 47% of fatal accidents; slippery road due to weather is cited in 13% of all accidents but 10% of fatal ones; travelling too fast for the conditions is cited in 9% of all accidents but 19% of fatal ones and exceeding speed limit is cited in 3% of all accidents but 13% of fatal ones.

2.5 Note that repeats of the same contributory factor within an accident are excluded from the table however an accident will appear more than once if more than one different contributory factor is reported.

Changes over time

2.6 Table N compares the top 10 contributory factors listed in 2011 against previous years. The ten factors remained the same in all five years, though the order and frequency changed over the 7 years of collection. The most frequently recorded factor, failed to look properly is associated with a larger proportion of accidents in 2011 than when the CF system was introduced in 2005.

2.7 It's not currently possible to identify whether changes are a result of reporting officers developing their understanding of the new system or a genuine change in the kinds of factors contributing to accidents reported to the police.

3. Vehicle & pedestrians

3.1 Tables O shows the number and percentage of vehicles assigned each type of contributory factor (for each vehicle involved in an accident reported to the police). Table P shows this for pedestrians only.

3.2 Tables O & P show that:

  • Failed to look properly was the most frequently reported factor both overall (reported in 19% of all vehicles' factors), and for every vehicle except bus or coaches and motorcyclists.
  • Sudden braking was the most frequently reported factor for bus or coaches (17%) whereas loss of control (24%) was the most commonly reported factor for motorcyclists.
  • Loss of control and failed to judge other person's path/speed were the second most common factors reported for cars or taxis (10%).
  • Failed to judge other person's speed/path was the second most common factor associated with cyclists (associated with 6% of bicycles).
  • Failed to judge other person's speed/path was the second most common factor reported for good vehicles (reported in 12%).
  • Travelling too fast for the conditions or excessive speed were associated with a total of 7% of all vehicles involved in reported accidents.
  • Pedestrians involved in accidents were most likely to have failed to look properly as an associated contributory factor (recorded in 45% of all pedestrians), followed by careless/reckless or in a hurry (19%), impaired by alcohol (13%), crossed road masked by stationary/parked vehicle (12%) and failed to judge vehicle speed/path (11%).

3.3 Table O also shows that many contributory factors were rarely recorded for most vehicles, for example:

  • loss of control was recorded for 24% of motorcycles but only 1% of vehicles in the bus/coach/minibus grouping;
  • sudden braking was recorded for 17% of buses but for only 4% of all vehicles involved.

3.4 On average, fewer contributory factors were recorded for pedal cycles (an average of 0.68 per cycle involved in a reported accident) and bus or coaches (an average e of 0.76), compared to an overall average of 1.10 factors per vehicles.

3.5 Note that percentages differ from Tables M & N which presents the percentage of accidents with each contributory factor. As more than one vehicle may be involved in an accident, the average number of factors associated with an individual vehicle is generally lower.

Pairing of factors

3.5 Table Q shows the most frequent pairs of contributory factors assigned to the same reported road accident participant in 2011.

  • The most frequently-occurring combination is driver/rider failed to look properly + (driver/rider) failed to judge other person's path/speed, which was recorded on 647 occasions.
  • As would be expected, the CFs identified (earlier) as most frequent to appear in several of the most frequently-occurring combinations - for example, (driver/rider) failed to look properly occurs in four of the ten most frequently-occurring combinations.

3.6 However, the numbers indicate that even the most frequently-occurring combination of CFs arose in only a small proportion of all accidents.

4 Casualties

4.1 Tables R & S show the number (and percentage) of fatal and seriously injured casualties involved in accidents where each contributory factor was reported. Unsurprisingly the pattern is similar to that seen in Tables M & N showing the number of accidents with each factor reported. Comparison shows that accidents with pedestrian only factors reported had lower numbers of casualties per accident.

4.2 Note a casualty will appear in the tables against each (unique) factor associated with the accident (resulting in the casualty) and therefore may appear more than once. As with the accident tables, repeats of the same contributory factor within an accident are excluded.

Fatalities

4.3 Table R shows the Contributory Factors associated with the largest numbers of deaths were:

  • loss of control - 88 deaths (representing 47% of all deaths in accidents for which CFs were recorded);
  • (driver/rider) failed to look properly - 40 (22%);
  • travelling too fast for the conditions 36 (19% of fatalities) and exceeding speed limit 25 (13% of fatalities) - one or other (or both) were recorded in 26 per cent of fatalities in 2011;
  • (driver/rider) careless / reckless /in a hurry - 22 (12%);
  • slippery road (due to weather) - 18 deaths (10%)
  • pedestrian failed to look properly - 18 deaths (10%)

Seriously injured

4.4 Table S shows the CFs associated with the largest numbers of serious injured were:

  • (driver/rider) failed to look properly - 482 serious injuries (representing 26% of all serious injuries in accidents for which CFs were recorded);
  • loss of control - 440 serious injuries (23%);
  • pedestrian failed to look properly - 279 (15%)
  • (driver/rider) careless / reckless / in a hurry - 261 (14%);
  • slippery road (due to weather) - 200 (11%)
  • travelling too fast for conditions - 197 (11%)

5 Overall frequencies of recording

5.1 In 2011 at least one contributory factor was recorded in 99.9% of reported accidents (9,974) - there were 7 accidents without a contributory factor. A total of 21,357 factors were recorded, resulting in an average of 2.11 factors per accident.

5.2 Around 86% (18,385) of all factors listed were related to vehicles (and their drivers/rider) and the road environment). Around 13% (2,811) were related to pedestrians who were casualties. Relatively few were uninjured pedestrians (315 or 1.5%).

5.3 Table T presents a ranking of all 77 factors by the frequency of reporting in 2011. (Note that figures differ from earlier tables as repeats of factors within the same accident are counted). It is apparent that some CFs are not used often - for example, many were used fewer than 100 times.

5.4 Note that data relating to all reported CFs were used to produce Tables O to T. In cases where the same CF applies to more than one vehicle in the same accident, it is counted once for each of them. These tables therefore differ from Tables M & N (which exclude repeats of the same CF within an accident).

Possible vs. Very likely

5.5 Reporting officers record whether it was thought very likely or just possible that a factor contributed to the occurrence of the accident. Table T also shows how often each CF was described as very likely, and how often as possible.

5.6 Overall, almost three-quarters of CFs (71%) were described as very likely, but the percentage varied markedly between different CFs. Excluding those used fewer than 100 times, the following were described as very likely on at least 85% of occasions on which they were used:

  • Crossed road masked by stationary/parked vehicle (88%)
  • Pedestrian impaired by alcohol (85%);

and the following were described as very likely on fewer than 64% of the occasions on which they were used:

  • Pedestrian failed to judge vehicles path or speed (64%)
  • Dazzling sun (63%)
  • Stationary or parked vehicle (63%)
  • Road layout (e.g. bend, hill, narrow carriageway) (58%)
  • Rain, sleet, snow or fog (48%)
  • Distraction in vehicle (39%)

Conclusion

The collection of contributory factors has been part of the GB wide police reporting system for 7 years. It's clear that the contributory factor information can provide useful indications of the circumstances that may have led to a reported road accident. These can also be attributed to the different participants within the accident, which can help build a picture of how the accident may have occurred.

However there are limitations to the system and care should be taken when both analysing and interpreting the results. This should help ensure that the data is used in the correct manner and that consistent messages/results are achieved by users.

We welcome comments on the analysis presented here or any questions regarding the contributory factor system.

Transport Statistics
Transport Scotland
Victoria Quay
Edinburgh EH6 6QQ

Telephone: 0131 244 7254
Email: Transtat@transportscotland.gsi.gov.uk

Background: The collection of Contributory Factor data

B1. Guidance on recording road accidents is provided in the Department for Transport's Stats20 document which includes the following points on CFs:

  • CFs reflect the reporting officer's opinion at the time of reporting, and may not be the result of extensive investigation;
  • subsequent enquiries could result in a change in the reporting officer's opinion;
  • the CFs are largely subjective, and depend upon the skill and experience of the investigating officer to reconstruct the events which led directly to the accident;
  • the need to exercise judgement when recording CFs is unavoidable;
  • CFs should be identified on the basis of evidence from sources such as witness statements and vehicle and site inspections;
  • the evidence may be of variable quality, so the officer should record very likely or possible for each CF;
  • when there is conflicting evidence (e.g. conflicting witness statements), the reporting officer should decide on the most credible account of the accident and base the codes on this, taking into account all other available evidence.

B2. Some CFs may be less likely than others to be recorded, since clear evidence of them may not be available, or may be very difficult to obtain, after an accident has occurred (e.g. in the case of the nervous, uncertain or panic factor). Participants and witnesses may provide incomplete or conflicting accounts of what happened. The CF data therefore depend upon the skill and experience of the reporting officer to reconstruct the events which led directly to the accident, and so are more subjective in nature than other Stats 19 data. This should be kept in mind when using these results.

B3. Regardless of the number of vehicles that were involved in the accident, at most six sets of CF data can be recorded per accident. Each set contains three pieces of information:

  • a factor which is thought to have contributed to the occurrence of the accident - selected from list of 77 , such as:
    • exceeding speed limit (CF code 306);
    • travelling too fast for the conditions (307);
    • failed to look properly (405);
    • impaired by alcohol (501);
    • impaired by drugs (illicit or medicinal) (502)
  • the participant in the accident to whom the factor is related:
    • whether this is a:
      • Vehicle - in which case the factor may relate to the driver/rider or to the road environment;
      • Casualty - a pedestrian or a passenger in a vehicle; or
      • Uninjured pedestrian.
    • if a Vehicle or a Casualty, the relevant Stats 19 reference
  • whether it was thought very likely or just possible that this factor contributed to the occurrence of the accident

Therefore more than one factor may be recorded for the same participant and any given factor may be recorded for two or more different participants, subject to the limit of a maximum of six sets of CF data per accident.

B4. Appendix B of this publication illustrates the CF codes and their descriptions, including a brief set of completion instructions for the reporting officer. More detailed information is available in the DfT's Stats 20 document (pages 10; 84 -101) and the procedure for allocating them - for example:

  • the CFs may be recorded in any order (so nothing can be inferred from the order in which they appear);
  • more than one CF may be related to the same road user; and
  • the same CF may be related to more than one road user.

Worked example

B5. Clearly, there could be a lot of CF information in the case of an accident which involved several vehicles, if it was thought that several of them contributed to its occurrence. The following is an example of the potential complexity of the CF data. Car 1 is rapidly travelling along a straight road when Car 2 suddenly appears in front of it, having emerged from a pub car park. The driver of Car 1 brakes sharply, to avoid a collision. As Car 2 drives off, Car 1 is hit from behind by a motorcycle, whose rider and passenger are both killed. The following might be recorded as the CF data for this accident:

CF no.

Participant

Contributory Factor

How likely?

1

Car 1

Exceeding speed limit

Possible

2

Car 2

Impaired by alcohol

Possible

3

Car 2

Failed to look properly

Very likely

4

Car 1

Sudden braking

Very likely

5

Motorcycle

Following too close

Very likely

6

Motorcycle

Exceeding speed limit

Possible

This accident has three participants and six CFs, two of which are the same (exceeding speed limit) but apply to different participants (Car 1 and Motorcycle). This example will be referred to from time to time, when describing some of the CF results.

Quality

B6. As the CFs were added to the Stats 19 data specification at the start of 2005, the results for 2005 could have been affected by teething troubles. In June 2006, the Liaison Group on Road Accident Statistics (LGRAS) discussed a paper on aspects of the quality of the data. It also remains the case the recording of CFs varies between Police Forces. In 2009, there were around 2.1 CFs per accident for Scotland; varying between 1.5 and 2.6 between Forces. In addition, while most Police Forces' CFs are allocated by the reporting officer, in one Force they are allocated by a small team of specialist crash investigators. It may be that a higher degree of accuracy exists for fatal and serious accidents than for slight accidents, as the former may be attended by more experienced road policing officers.

B7. On introduction inconsistencies arose between the CF code and the Type of Participant code (around 3-4% in 2005). The most frequent problem was the combination of the CF code for pedestrian failed to look properly with the Type of Participant code for a Vehicle. In such cases, it wasn't possible to deduce (from the data) which was incorrect. Since then additional quality assurance was introduced leading to an improvement in quality (currently around 1% of cases).

B8. There may be other changes in some of the patterns of the reporting of CFs, as a result of such discussions, the introduction of additional computer cross-checks of the data, Police Forces' increasing experience of the collection and recording of such information, and the use of the data by the Police, local authorities and central government.

Table M: Contributory Factors: Reported accidents1,2 by severity, 2011
Fatal Serious Slight All accidents
Contributory factor reported in accident Number Per cent3 Number Per cent3 Number Per cent3 Number Per cent3
Road environment contributed 5 24 14 291 16 1,571 19 1,886 19
Poor or defective road surface 1 1 19 1 86 1 106 1
Deposit on road (e.g oil, mud, chippings) 2 1 41 2 151 2 194 2
Slippery road (due to weather) 17 10 174 9 1,120 14 1,311 13
Inadequate/masked signs or road markings 1 1 5 0 59 1 65 1
Defective traffic signals 0 0 1 0 12 0 13 0
Traffic calming (e.g road humps, chicanes) 0 0 1 0 7 0 8 0
Temporary road layout (e.g contraflow) 0 0 6 0 29 0 35 0
Road layout (e.g bend, hill, narrow c-way) 5 3 61 3 228 3 294 3
Animal or other object in carriageway 1 1 26 1 115 1 142 1
Vehicle defects 5 6 3 24 1 113 1 143 1
Tyres illegal, defective or under-inflated 3 2 4 0 39 0 46 0
Defective lights or indicators 0 0 3 0 10 0 13 0
Defective brakes 1 1 9 0 33 0 43 0
Defective steering or suspension 1 1 4 0 18 0 23 0
Overloaded or poorly loaded vehicle/trailer 1 1 6 0 17 0 24 0
Injudicious action (driver/rider) 5 53 30 349 19 1,874 23 2,276 23
Disobeyed automatic traffic signal 1 1 16 1 140 2 157 2
Disobeyed Give Way or Stop sign or markings 0 0 49 3 309 4 358 4
Disobeyed double white line 1 1 7 0 11 0 19 0
Disobeyed pedestrian crossing facility 2 1 10 1 27 0 39 0
Illegal turn or direction of travel 4 2 16 1 40 0 60 1
Exceeding speed limit 22 13 75 4 232 3 329 3
Travelling too fast for the conditions 34 19 166 9 705 9 905 9
Following too close 3 2 29 2 524 6 556 6
Vehicle travelling along pavement 0 0 7 0 12 0 19 0
Cyclist entering road from pavement 0 0 13 1 48 1 61 1
Driver/rider error or reaction 5 128 73 1,000 54 5,458 67 6,586 66
Junction overshoot 0 0 23 1 187 2 210 2
Junction restart 0 0 8 0 42 1 50 1
Poor turn or manoeuvre 16 9 192 10 905 11 1,113 11
Failed to signal/misleading signal 0 0 8 0 85 1 93 1
Failed to look properly (D/R) 37 21 439 24 2,673 33 3,149 32
Failed to judge other pers path/speed (D/R) 14 8 159 9 1,364 17 1,537 15
Passing too close to cyclist/horse/pedestrian 2 1 36 2 174 2 212 2
Sudden braking 6 3 74 4 503 6 583 6
Swerved 9 5 49 3 265 3 323 3
Loss of control 82 47 356 19 1,289 16 1,727 17
Impairment or distraction (driver/rider) 5 42 24 194 11 718 9 954 10
Impaired by alcohol (D/R) 19 11 77 4 274 3 370 4
Impaired by drugs (illicit/medicinal) (D/R) 4 2 9 0 46 1 59 1
Fatigue 8 5 27 1 78 1 113 1
Uncorrected defective eyesight 2 1 6 0 5 0 13 0
Illness or disability (mental/physic) (D/R) 13 7 31 2 99 1 143 1
Not display lights at night/in poor visib 0 0 7 0 14 0 21 0
Cyclist wearing dark clothing at night 1 1 8 0 17 0 26 0
Driver using mobile phone 0 0 5 0 10 0 15 0
Distraction in vehicle 5 3 36 2 144 2 185 2
Distraction outside vehicle 0 0 14 1 93 1 107 1
Behaviour or inexperience (driver/rider) 5 43 24 327 18 1,343 17 1,713 17
Aggressive driving 10 6 40 2 143 2 193 2
Careless/reckless/in a hurry (D/R) 22 13 218 12 885 11 1,125 11
Nervous/uncertain/panic 1 1 18 1 97 1 116 1
Driving too slow for condits/slow vehicle 0 0 1 0 6 0 7 0
Inexperienced or learner driver/rider 11 6 72 4 253 3 336 3
Inexperience of driving on the left 3 2 12 1 40 0 55 1
Inexperience with type of vehicle 2 1 16 1 51 1 69 1
Vision affected5 17 10 140 8 643 8 800 8
Stationary or parked vehicle 2 1 35 2 148 2 185 2
Vegetation 1 1 4 0 9 0 14 0
Road layout (e.g bend, winding rd, hill crest 1 1 28 2 63 1 92 1
Buildings, road signs, street furniture 0 0 3 0 14 0 17 0
Dazzling headlights 1 1 2 0 15 0 18 0
Dazzling sun 4 2 29 2 179 2 212 2
Rain, sleet, snow or fog 6 3 24 1 172 2 202 2
Spray from other vehicles 2 1 1 0 18 0 21 0
Visor or windscreen dirty or scratched 0 0 2 0 4 0 6 0
Vehicle blind spot 2 1 19 1 68 1 89 1
Pedestrian only 5 32 18 416 23 1,129 14 1,577 16
Crossed road masked by stationary/parked veh 2 1 75 4 203 2 280 3
Pedestrian failed to look properly 18 10 276 15 791 10 1,085 11
Ped. failed to judge vehicles path or speed 12 7 73 4 167 2 252 3
Wrong use of pedestrian crossing facility 0 0 33 2 65 1 98 1
Dangerous action in carriageway (e.g playing) 7 4 41 2 99 1 147 1
Pedestrian impaired by alcohol 14 8 97 5 197 2 308 3
Ped. impaired by drugs (illicit/medicinal) 2 1 13 1 23 0 38 0
Ped. careless/reckless/in a hurry 7 4 111 6 334 4 452 5
Pedestrian wearing dark clothing at night 10 6 47 3 51 1 108 1
Ped. disability or illness, mental/physical 2 1 16 1 39 0 57 1
Special codes 5 14 8 65 4 329 4 408 4
Stolen vehicle 2 1 8 0 37 0 47 0
Vehicle in course of crime 1 1 4 0 18 0 23 0
Emergency vehicle on call 2 1 3 0 21 0 26 0
Vehicle door opened or closed negligently 0 0 4 0 25 0 29 0
Other 10 6 47 3 235 3 292 3
Total reported accidents1 176 1,847 8,127 9,974 100
Number of Contributory Factors4 481 3,742 17,134 21,357
Average number of CFs per accident1,4 2.7 2.0 2.1 2.1

1 Includes only accidents where a police officer attended the scene.
2 Includes only one count of a CF per accident.
3 Columns won't sum to 100 per cent as accidents can have more than one CF.
4 Includes all contributory factors eg if two cars are involved in the same accident and both are exceeding the speed limit this would count as 2 CFs.
5 Accidents with more than one CF in a category are only counted once in the category total.

Table N: Contributory factors: Reported Accidents: 2007-2011 comparison1
Contributory factor reported in accident2 2007 2008 2009 2010 2011
Number Per cent3 Number Per cent3 Number Per cent3 Number Per cent3 Number Per cent3
Failed to look properly (D/R) 3,343 27 3,371 28 3,303 29 3,056 30 3,149 32
Loss of control 2,280 18 2,267 19 2,258 20 1,880 18 1,727 17
Failed to judge other pers path/speed (D/R) 1,881 15 1,997 16 1,906 16 1,699 17 1,537 15
Slippery road (due to weather) 1,479 12 1,662 14 1,688 15 1,690 16 1,311 13
Poor turn or manoeuvre 1,413 11 1,359 11 1,397 12 1,180 11 1,113 11
Careless/reckless/in a hurry (D/R) 1,664 13 1,520 13 1,357 12 1,115 11 1,125 11
Travelling too fast for the conditions 1,224 10 1,203 10 1,221 11 1,067 10 905 9
Pedestrian failed to look properly 1,460 12 1,389 11 1,170 10 1,059 10 1,085 11
Sudden braking 791 6 800 7 707 6 634 6 583 6
Following too close 689 6 608 5 646 6 613 6 556 6
Total reported accidents1 12,506 100 12,158 100 11,556 100 10,295 100 9,974 100

1 Includes only accidents where a police officer attended the scene and in which a contributory factor was reported.
2 Includes only the ten most frequently reported contributory factor citied in 2011. Factors not shown may also have been reported.
3 Columns won't sum to 100 per cent as accidents can have more than one CF

Table O: Contributory factors: vehicles, 2011
Pedal cycle Motorcycle Car & Taxis Bus, coach & minibus Goods Other All vehicles
Number % Number % Number % Number % Number % Number % Number %
Road environment contributed 3 19 2 144 17 1,497 12 29 4 39 3 110 30 1,838 11
Poor or defective road surface 8 1 19 2 71 1 1 0 3 0 1 0 103 1
Deposit on road (eg oil, mud, chippings) 1 0 44 5 130 1 3 0 8 1 7 2 193 1
Slippery road (due to weather) 6 1 60 7 1,158 9 16 2 88 7 25 7 1,353 8
Inadequate/masked signs or road markings 1 0 0 0 57 0 4 1 3 0 2 1 67 0
Defective traffic signals 0 0 1 0 14 0 0 0 1 0 0 0 16 0
Traffic calming (eg road humps, chicanes) 0 0 0 0 5 0 1 0 1 0 1 0 8 0
Temporary road layout (eg contraflow) 2 0 2 0 27 0 1 0 3 0 1 0 36 0
Road layout (eg bend, hill, narrow c-way) 4 0 12 1 268 2 6 1 18 1 7 2 315 2
Animal or other object in carriageway 1 0 24 3 100 1 2 0 6 0 3 1 136 1
Vehicle defects3 14 2 12 1 82 1 5 1 7 1 23 6 143 1
Tyres illegal, defective or under-inflated 0 0 2 0 40 0 0 0 4 0 0 0 46 0
Defective lights or indicators 4 0 1 0 6 0 1 0 0 0 1 0 13 0
Defective brakes 11 1 6 1 18 0 2 0 5 0 1 0 43 0
Defective steering or suspension 0 0 1 0 18 0 1 0 2 0 1 0 23 0
Overloaded or poorly loaded vehicle/trailer 0 0 2 0 2 0 1 0 14 1 5 1 24 0
Injudicious action (driver/rider)3 94 11 114 14 1,824 14 37 6 43 3 164 45 2,276 14
Disobeyed automatic traffic signal 9 1 6 1 133 1 5 1 9 1 6 2 168 1
Disobeyed Give Way or Stop sign or markings 8 1 5 1 317 2 3 0 19 2 7 2 359 2
Disobeyed double white line 0 0 2 0 13 0 0 0 3 0 1 0 19 0
Disobeyed pedestrian crossing facility 5 1 1 0 23 0 5 1 3 0 2 1 39 0
Illegal turn or direction of travel 4 0 3 0 49 0 0 0 4 0 1 0 61 0
Exceeding speed limit 1 0 29 4 282 2 3 0 14 1 6 2 335 2
Travelling too fast for the conditions 18 2 63 8 746 6 7 1 64 5 15 4 913 5
Following too close 2 0 19 2 487 4 18 3 56 4 9 2 591 4
Vehicle travelling along pavement 6 1 2 0 8 0 0 0 2 0 1 0 19 0
Cyclist entering road from pavement 53 6 0 0 8 0 0 0 0 0 0 0 61 0
Driver/rider error or reaction3 203 24 358 43 5,115 40 223 33 146 12 540 148 6,585 39
Junction overshoot 13 2 3 0 180 1 1 0 10 1 3 1 210 1
Junction restart 1 0 2 0 43 0 2 0 2 0 0 0 50 0
Poor turn or manoeuvre 27 3 62 7 860 7 43 6 120 10 33 9 1,145 7
Failed to signal/misleading signal 5 1 1 0 72 1 3 0 7 1 6 2 94 1
Failed to look properly (D/R) 133 16 86 10 2,614 20 74 11 250 20 77 21 3,234 19
Failed to judge other pers path/speed (D/R) 48 6 76 9 1,239 10 54 8 149 12 42 12 1,608 10
Passing too close to cyclist/horse/pedestri 6 1 3 0 150 1 12 2 28 2 13 4 212 1
Sudden braking 4 0 63 8 383 3 111 17 35 3 16 4 612 4
Swerved 13 2 22 3 258 2 5 1 26 2 5 1 329 2
Loss of control 47 5 202 24 1,334 10 9 1 111 9 27 7 1,730 10
Impairment or distraction (driver/rider) 3 35 4 27 3 812 6 9 1 16 1 54 15 953 6
Impaired by alcohol (D/R) 7 1 19 2 323 3 2 0 13 1 7 2 371 2
Impaired by drugs (illicit/medicinal) (D/R) 0 0 2 0 55 0 0 0 1 0 1 0 59 0
Fatigue 0 0 1 0 92 1 0 0 18 1 3 1 114 1
Uncorrected defective eyesight 0 0 0 0 13 0 0 0 0 0 0 0 13 0
Illness or disability (mental/physic) (D/R) 3 0 0 0 131 1 1 0 6 0 2 1 143 1
Not display lights at night/in poor visib 15 2 1 0 3 0 0 0 0 0 2 1 21 0
Cyclist wearing dark clothing at night 22 3 2 0 2 0 0 0 0 0 0 0 26 0
Driver using mobile phone 1 0 0 0 13 0 0 0 0 0 1 0 15 0
Distraction in vehicle 0 0 1 0 168 1 3 0 13 1 0 0 185 1
Distraction outside vehicle 1 0 4 0 88 1 4 1 12 1 1 0 110 1
Behaviour or inexperience (driver/rider) 3 56 7 132 16 1,345 11 34 5 43 3 101 28 1,711 10
Aggressive driving 6 1 13 2 156 1 3 0 11 1 6 2 195 1
Careless/reckless/in a hurry (D/R) 40 5 58 7 900 7 28 4 84 7 28 8 1,138 7
Nervous/uncertain/panic 4 0 9 1 99 1 1 0 1 0 2 1 116 1
Driving too slow for condits/slow vehicle 0 0 0 0 3 0 0 0 1 0 3 1 7 0
Inexperienced or learner driver/rider 8 1 53 6 271 2 1 0 2 0 2 1 337 2
Inexperience of driving on the left 0 0 8 1 41 0 1 0 3 0 2 1 55 0
Inexperience with type of vehicle 4 0 16 2 42 0 2 0 3 0 3 1 70 0
Vision affected3 16 2 24 3 652 5 15 2 18 1 75 21 800 5
Stationary or parked vehicle 6 1 6 1 164 1 5 1 13 1 3 1 197 1
Vegetation 2 0 1 0 10 0 0 0 3 0 1 0 17 0
Road layout (eg bend, winding rd, hill crest 4 0 9 1 69 1 3 0 10 1 5 1 100 1
Buildings, road signs, street furniture 0 0 0 0 16 0 0 0 1 0 0 0 17 0
Dazzling headlights 0 0 1 0 17 0 0 0 0 0 0 0 18 0
Dazzling sun 5 1 6 1 185 1 5 1 14 1 2 1 217 1
Rain, sleet, snow or fog 3 0 7 1 178 1 4 1 14 1 5 1 211 1
Spray from other vehicles 0 0 4 0 17 0 0 0 2 0 0 0 23 0
Visor or windscreen dirty or scratched 0 0 0 0 5 0 0 0 1 0 0 0 6 0
Vehicle blind spot 1 0 0 0 54 0 3 0 26 2 6 2 90 1
Special codes 3 5 1 15 2 212 2 46 7 22 2 34 9 334 2
Stolen vehicle 0 0 5 1 38 0 1 0 1 0 2 1 47 0
Vehicle in course of crime 0 0 1 0 19 0 1 0 1 0 1 0 23 0
Emergency vehicle on call 0 0 1 0 13 0 1 0 2 0 9 2 26 0
Vehicle door opened or closed negligently 1 0 0 0 21 0 1 0 4 0 2 1 29 0
Other 4 0 9 1 127 1 44 7 30 2 10 3 224 1
Number of vehicle Contributory Factors1 578 1,061 14,446 508 1,358 434 18,385
Total number of vehicles involved2 855 100% 828 100% 12,778 100% 666 100% 1,247 100% 365 100% 16,739 100%
Average number of CFs per vehicle2 0.68 1.28 1.13 0.76 1.09 1.19 1.10

1. Excludes invalid codes or pedestrian only factors incorrectly assigned to a vehicle.
2. Includes those without any CFs.
3. Vehicles with more than one CF in a category are only counted once in the category total.

Table P: Contributory factors: pedestrians1, 2011
Number %
Pedestrian failed to look properly 1,079 45
Ped. Careless/reckless/in a hurry 450 19
Pedestrian impaired by alcohol 305 13
Crossed road masked by stationary/parked veh 280 12
Ped. Failed to judge vehicles path or speed 250 11
Dangerous action in carriageway (eg playing) 147 6
Pedestrian wearing dark clothing at night 107 5
Wrong use of pedestrian crossing facility 98 4
Ped. Disability or illness, mental/physical 57 2
Ped. Impaired by drugs (illicit/medicinal) 38 2
Number of Contributory Factors2 2,811
Total number of pedestrians involved1 2,374
Average number of CFs per pedestrian 1.18

1. Includes pedestrians injured and non injured in the accident
2. Excludes pedestrians incorrectly attributed a vehicle factor or special code

Table Q: Most common pairs of contributory factors reported together, 2011
Factor with lower code Factor with higher code Number
Failed to look properly (D/R) Failed to judge other pers path/speed (D/R) 647
Poor turn or manoeuvre Failed to look properly (D/R) 513
Slippery road (due to weather) Loss of control 455
Travelling too fast for the conditions Loss of control 416
Failed to look properly (D/R) Careless/reckless/in a hurry (D/R) 410
Slippery road (due to weather) Travelling too fast for the conditions 328
Pedestrian failed to look properly Ped. Careless/reckless/in a hurry 314
Disobeyed Give Way or Stop sign or markings Failed to look properly (D/R) 236
Poor turn or manoeuvre Failed to judge other pers path/speed (D/R) 228
Crossed road masked by stationary/parked veh Pedestrian failed to look properly 210
Loss of control Careless/reckless/in a hurry (D/R) 207
Failed to judge other pers path/speed (D/R) Careless/reckless /in a hurry (D/R) 204
Following too close Failed to judge other pers path/speed (D/R) 189
Pedestrian failed to look properly Ped. Failed to judge vehicles path or speed 178
Following too close Failed to look properly (D/R) 155
Poor turn or manoeuvre Careless/reckless/in a hurry (D/R) 154
Loss of control Impaired by alcohol (D/R) 150
Pedestrian failed to look properly Pedestrian impaired by alcohol 147
Travelling too fast for the conditions Careless/reckless/in a hurry (D/R) 138
Swerved Loss of control 138
Exceeding speed limit Loss of control 137
Poor turn or manoeuvre Loss of control 125
Loss of control Inexperienced or learner driver/rider 122
Slippery road (due to weather) Road layout (eg bend, hill, narrow c-way) 117
Exceeding speed limit Careless/reckless/in a hurry (D/R) 113
Sudden braking Loss of control 106
Travelling too fast for the conditions Failed to look properly (D/R) 102
Slippery road (due to weather) Rain, sleet, snow or fog 100
Junction overshoot Failed to look properly (D/R) 100

NOTE: the basis upon which the combinations are produced is described in the text.
However, an additional example may be helpful.
Suppose that the "defective brakes" CF has been allocated to participant A,
the "failed to look properly" CF has been allocated to two participants A and B, and
the "failed to judge other person's path/speed" CF has been allocated to participants A, B and C,
The following combinations of CFs would be allocated to the same participant:
A defective brakes + A failed to look …
A defective brakes + A failed to judge …
A failed to look ... + A failed to judge …
B failed to look ... + B failed to judge …

Table R: Contributory factors: Casualties in reported accidents - fatalities, 2011
Person who was killed
as a % of all fatalities
Pedestrian pedalcyclist motorcyclist Car/taxi user Other All
Road environment contributed
Poor or defective road surface 0 0 1 0 0 1 1
Deposit on road (eg oil, mud, chippings) 0 0 1 1 0 2 1
Slippery road (due to weather) 0 0 0 15 3 18 10
Inadequate/masked signs or road markings 0 1 0 0 0 1 1
Road layout (eg bend, hill, narrow c-way) 0 1 1 3 1 6 3
Animal or other object in carriageway 0 0 1 0 0 1 1
Vehicle defects
Tyres illegal, defective or under-inflated 0 0 1 2 0 3 2
Defective brakes 0 0 1 0 0 1 1
Defective steering or suspension 0 0 1 0 0 1 1
Overloaded or poorly loaded vehicle/trailer 0 0 1 0 0 1 1
Injudicious action (driver/rider)
Disobeyed automatic traffic signal 0 0 0 1 0 1 1
Disobeyed double white line 0 0 0 1 0 1 1
Disobeyed pedestrian crossing facility 2 0 0 0 0 2 1
Illegal turn or direction of travel 0 0 0 5 0 5 3
Exceeding speed limit 1 0 7 17 0 25 13
Travelling too fast for the conditions 4 1 6 25 0 36 19
Following too close 0 0 2 0 1 3 2
Driver/rider error or reaction
Poor turn or manoeuvre 0 0 6 9 2 17 9
Failed to look properly (D/R) 17 1 10 10 2 40 22
Failed to judge other pers path/speed (D/R) 4 0 2 6 2 14 8
Passing too close to cyclist/horse/pedestri 2 0 0 0 0 2 1
Sudden braking 0 0 3 2 1 6 3
Swerved 0 1 2 3 3 9 5
Loss of control 2 3 17 59 7 88 47
Impairment or distraction (driver/rider)
Impaired by alcohol (D/R) 1 0 1 16 2 20 11
Impaired by drugs (illicit/medicinal) (D/R) 1 0 0 3 1 5 3
Fatigue 0 0 0 8 0 8 4
Uncorrected defective eyesight 1 1 0 0 0 2 1
Illness or disability (mental/physic) (D/R) 1 0 0 13 1 15 8
Cyclist wearing dark clothing at night 0 1 0 0 0 1 1
Distraction in vehicle 2 0 0 3 0 5 3
Behaviour or inexperience (driver/rider)
Aggressive driving 1 0 3 7 0 11 6
Careless/reckless/in a hurry (D/R) 5 2 6 8 1 22 12
Nervous/uncertain/panic 0 0 1 0 0 1 1
Inexperienced or learner driver/rider 1 0 5 6 0 12 6
Inexperience of driving on the left 0 0 1 2 0 3 2
Inexperience with type of vehicle 0 0 0 3 0 3 2
Vision affected
Stationary or parked vehicle 2 0 0 0 0 2 1
Vegetation 0 0 1 0 0 1 1
Road layout (eg bend, winding rd, hill crest 0 0 1 0 0 1 1
Dazzling headlights 1 0 0 0 0 1 1
Dazzling sun 1 0 1 1 1 4 2
Rain, sleet, snow or fog 3 1 0 2 0 6 3
Spray from other vehicles 0 0 1 0 1 2 1
Vehicle blind spot 1 1 0 0 0 2 1
Pedestrian only
Crossed road masked by stationary/parked veh 2 0 0 0 0 2 1
Pedestrian failed to look properly 18 0 0 0 0 18 10
Ped. failed to judge vehicles path or speed 12 0 0 0 0 12 6
Dangerous action in carriageway (eg playing) 7 0 0 0 0 7 4
Pedestrian impaired by alcohol 14 0 0 0 0 14 8
Ped. impaired by drugs (illicit/medicinal) 2 0 0 0 0 2 1
Ped. careless/reckless/in a hurry 7 0 0 0 0 7 4
Pedestrian wearing dark clothing at night 10 0 0 0 0 10 5
Ped. disability or illness, mental/physical 2 0 0 0 0 2 1
Special codes
Stolen vehicle 1 0 1 0 0 2 1
Vehicle in course of crime 1 0 0 0 0 1 1
Emergency vehicle on call 0 0 0 1 1 2 1
Other 3 0 2 2 3 10 5
Total Road fatalities 43 7 33 90 13 186 100%

NB: As described in the text, an accident will be counted once for each combination of CF (excluding "repeats") and death.
For example, an accident with four different CFs and three deaths would be counted twelve times in this table - each death would be counted against the first CF, then against the second CF, and so on. As a result, the percentages would total far more than 100%.
However, "repeats" are excluded: if the same CF applies to two different participants, each death will be counted only once against that CF.

Table S: Contributory factors: Casualties in reported accidents - seriously injured, 2011
Person who was seriously injured as a % of all seriously injured casualties
Pedestrian pedalcyclist motorcyclist Car/taxi user Other All
Road environment contributed
Poor or defective road surface 0 4 6 13 1 24 1
Deposit on road (eg oil, mud, chippings) 2 0 17 37 1 57 3
Slippery road (due to weather) 10 1 21 148 20 200 11
Inadequate/masked signs or road markings 1 0 0 4 0 5 0
Defective traffic signals 0 0 0 0 1 1 0
Traffic calming (eg road humps, chicanes) 0 0 0 0 1 1 0
Temporary road layout (eg contraflow) 1 1 1 3 0 6 0
Road layout (eg bend, hill, narrow c-way) 2 2 15 54 5 78 4
Animal or other object in carriageway 0 2 14 11 0 27 1
Vehicle defects
Tyres illegal, defective or under-inflated 3 0 1 4 0 8 0
Defective lights or indicators 0 2 1 0 0 3 0
Defective brakes 0 3 1 4 1 9 0
Defective steering or suspension 0 0 0 2 4 6 0
Overloaded or poorly loaded vehicle/trailer 0 0 1 4 2 7 0
Injudicious action (driver/rider)
Disobeyed automatic traffic signal 5 1 5 5 1 17 1
Disobeyed Give Way or Stop sign or markings 1 15 5 35 2 58 3
Disobeyed double white line 0 0 3 8 1 12 1
Disobeyed pedestrian crossing facility 9 1 1 0 0 11 1
Illegal turn or direction of travel 1 1 3 18 1 24 1
Exceeding speed limit 4 3 11 70 6 94 5
Travelling too fast for the conditions 7 5 31 138 16 197 11
Following too close 0 2 5 23 4 34 2
Vehicle travelling along pavement 5 0 2 1 0 8 0
Cyclist entering road from pavement 0 13 0 0 0 13 1
Driver/rider error or reaction
Junction overshoot 0 4 1 20 1 26 1
Junction restart 2 1 1 5 0 9 0
Poor turn or manoeuvre 19 20 60 105 17 221 12
Failed to signal/misleading signal 0 1 1 5 2 9 0
Failed to look properly (D/R) 113 84 94 163 28 482 26
Failed to judge other pers path/speed (D/R) 16 24 45 83 11 179 10
Passing too close to cyclist/horse/pedestrian 13 22 0 1 0 36 2
Sudden braking 5 4 23 27 25 84 4
Swerved 7 3 14 34 5 63 3
Loss of control 7 17 92 294 30 440 23
Impairment or distraction (driver/rider)
Impaired by alcohol (D/R) 5 2 8 76 3 94 5
Impaired by drugs (illicit/medicinal) (D/R) 2 0 0 9 2 13 1
Fatigue 3 0 2 30 6 41 2
Uncorrected defective eyesight 1 1 2 4 0 8 0
Illness or disability (mental/physic) (D/R) 2 2 0 30 7 41 2
Not display lights at night/in poor visib 0 6 0 2 0 8 0
Cyclist wearing dark clothing at night 0 8 0 0 0 8 0
Driver using mobile phone 1 1 1 3 0 6 0
Distraction in vehicle 2 2 1 43 5 53 3
Distraction outside vehicle 3 0 1 10 1 15 1
Behaviour or inexperience (driver/rider)
Aggressive driving 6 4 8 28 5 51 3
Careless/reckless/in a hurry (D/R) 32 20 46 150 13 261 14
Nervous/uncertain/panic 1 3 2 14 1 21 1
Driving too slow for condits/slow vehicle 0 0 1 0 0 1 0
Inexperienced or learner driver/rider 1 6 17 65 4 93 5
Inexperience of driving on the left 0 0 4 17 0 21 1
Inexperience with type of vehicle 1 1 7 11 1 21 1
Vision affected
Stationary or parked vehicle 28 1 3 3 0 35 2
Vegetation 0 2 3 0 0 5 0
Road layout (eg bend, winding rd, hill crest 1 2 9 14 5 31 2
Buildings, road signs, street furniture 0 0 3 0 0 3 0
Dazzling headlights 0 0 0 1 1 2 0
Dazzling sun 5 8 5 12 1 31 2
Rain, sleet, snow or fog 7 0 5 12 3 27 1
Spray from other vehicles 0 0 2 0 0 2 0
Visor or windscreen dirty or scratched 2 0 0 1 0 3 0
Vehicle blind spot 10 3 2 4 0 19 1
Pedestrian only
Crossed road masked by stationary/parked veh 75 0 1 0 0 76 4
Pedestrian failed to look properly 269 4 1 3 2 279 15
Ped. Failed to judge vehicles path or speed 73 0 0 0 0 73 4
Wrong use of pedestrian crossing facility 33 1 0 0 0 34 2
Dangerous action in carriageway (eg playing) 41 0 0 0 0 41 2
Pedestrian impaired by alcohol 96 0 0 2 0 98 5
Ped. Impaired by drugs (illicit/medicinal) 13 0 0 0 0 13 1
Ped. Careless/reckless/in a hurry 109 1 0 0 2 112 6
Pedestrian wearing dark clothing at night 47 0 0 0 0 47 3
Ped. Disability or illness, mental/physical 14 0 0 2 0 16 1
Special codes
Stolen vehicle 1 0 2 4 2 9 0
Vehicle in course of crime 3 0 0 0 1 4 0
Emergency vehicle on call 0 0 0 4 0 4 0
Vehicle door opened or closed negligently 0 3 0 1 0 4 0
Other 12 2 5 18 13 50 3
All serious injuries 513 156 293 779 134 1,875 100%

NB: As described in the text, an accident will be counted once for each combination of CF (excluding "repeats") and serious injury.
For example, an accident with four different CFs and three serious injury would be counted twelve times in this table - each serious injury would be counted against the first CF, then against the second CF, and so on. As a result, the percentages would total far more than 100%.
However, "repeats" are excluded: if the same CF applies to two different participants, each serious injury will be counted only once against that CF.

Table T: Contributory factors: ranked1, 2011
Rank Contributory Factor reported in each accident Number As a % of all contributory factors1
Very likely Possible Total
1 Failed to look properly (D/R) 2,498 737 3,235 15%
2 Loss of control 1,464 267 1,731 8%
3 Failed to judge other pers path/speed (D/R) 1,072 537 1,609 8%
4 Slippery road (due to weather) 1,040 335 1,375 6%
5 Poor turn or manoeuvre 848 297 1,145 5%
6 Careless/reckless/in a hurry (D/R) 700 439 1,139 5%
7 Pedestrian failed to look properly 915 175 1,090 5%
8 Travelling too fast for the conditions 489 424 913 4%
9 Sudden braking 431 181 612 3%
10 Following too close 333 258 591 3%
11 Ped. Careless/reckless/in a hurry 357 97 454 2%
12 Impaired by alcohol (D/R) 299 72 371 2%
13 Disobeyed Give Way or Stop sign or markings 309 50 359 2%
14 Inexperienced or learner driver/rider 212 125 337 2%
15 Exceeding speed limit 159 176 335 2%
16 Swerved 239 90 329 2%
17 Road layout (eg bend, hill, narrow c-way) 186 137 323 2%
18 Pedestrian impaired by alcohol 262 46 308 1%
19 Other 258 42 300 1%
20 Crossed road masked by stationary/parked veh 249 33 282 1%
21 Ped. Failed to judge vehicles path or speed 162 90 252 1%
22 Dazzling sun 137 80 217 1%
23 Passing too close to cyclist/horse/pedestri 150 62 212 1%
24 Rain, sleet, snow or fog 101 110 211 1%
25 Junction overshoot 159 51 210 1%
26 Stationary or parked vehicle 124 74 198 1%
27 Deposit on road (eg oil, mud, chippings) 143 55 198 1%
28 Aggressive driving 152 44 196 1%
29 Distraction in vehicle 72 113 185 1%
30 Disobeyed automatic traffic signal 126 42 168 1%
31 Dangerous action in carriageway (eg playing) 122 26 148 1%
32 Animal or other object in carriageway 113 33 146 1%
33 Illness or disability (mental/physic) (D/R) 90 53 143 1%
34 Nervous/uncertain/panic 53 63 116 1%
35 Fatigue 51 63 114 1%
36 Distraction outside vehicle 62 49 111 1%
37 Pedestrian wearing dark clothing at night 89 19 108 1%
38 Poor or defective road surface 68 38 106 0%
39 Wrong use of pedestrian crossing facility 77 23 100 0%
40 Road layout (eg bend, winding rd, hill crest 55 45 100 0%
41 Failed to signal/misleading signal 50 44 94 0%
42 Vehicle blind spot 41 49 90 0%
43 Inexperience with type of vehicle 33 37 70 0%
44 Inadequate/masked signs or road markings 36 33 69 0%
45 Illegal turn or direction of travel 54 7 61 0%
46 Cyclist entering road from pavement 51 10 61 0%
47 Impaired by drugs (illicit/medicinal) (D/R) 40 19 59 0%
48 Ped. Disability or illness, mental/physical 34 23 57 0%
49 Inexperience of driving on the left 39 16 55 0%
50 Junction restart 37 13 50 0%
51 Stolen vehicle 42 5 47 0%
52 Tyres illegal, defective or under-inflated 26 20 46 0%
53 Defective brakes 21 22 43 0%
54 Disobeyed pedestrian crossing facility 31 8 39 0%
55 Ped. Impaired by drugs (illicit/medicinal) 19 19 38 0%
56 Temporary road layout (eg contraflow) 13 25 38 0%
57 Vehicle door opened or closed negligently 26 3 29 0%
58 Emergency vehicle on call 22 4 26 0%
59 Cyclist wearing dark clothing at night 21 5 26 0%
60 Overloaded or poorly loaded vehicle/trailer 11 13 24 0%
61 Vehicle in course of crime 21 2 23 0%
62 Defective steering or suspension 9 14 23 0%
63 Spray from other vehicles 13 10 23 0%
64 Not display lights at night/in poor visib 17 4 21 0%
65 Vehicle travelling along pavement 16 3 19 0%
66 Disobeyed double white line 18 1 19 0%
67 Dazzling headlights 9 9 18 0%
68 Buildings, road signs, street furniture 10 7 17 0%
69 Vegetation 9 8 17 0%
70 Defective traffic signals 12 4 16 0%
71 Driver using mobile phone 5 10 15 0%
72 Defective lights or indicators 7 6 13 0%
73 Uncorrected defective eyesight 4 9 13 0%
74 Traffic calming (eg road humps, chicanes) 4 4 8 0%
75 Driving too slow for condits/slow vehicle 4 3 7 0%
76 Visor or windscreen dirty or scratched 5 1 6 0%
All 15,236 6,121 21,357 100%

1. Includes all contributory factors reported, even where the same CF is assigned more than once to an accident
(i.e. to more than one particpant). Therefore the total differs from earlier tables.
(D/R) indicates Driver/Rider