On-scene investigations - Phase 1 and Phase 2 crashes
The following tables and figures have been provided to give an outline of the type and distribution of accidents recorded within the OTS Phase 1and Phase 2 database. Please note that the percentages shown are sometimes rounded and therefore the totals might be slightly less than 100%. |
Table A1.1: Accident severity distributions for accidents sampled
Table A1.1 breaks down the crashes attended in Phase 1 and Phase 2 by the police recorded injury severity of the accident. The UK Government’s STATS19 database contains details of all injury road traffic accidents which are reported to the police.
Table A1.2 shows a comparison between the samples of injury road traffic accident attended by the OTS teams within the OTS sample regions against those recorded in STATS19 (Road Casualties Great Britain 2003) [20].
Table A1.2: Injury accident severity distributions (OTS and STATS19)
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Table A1.3: Road user type classification
The OTS sample is skewed towards more serious accidents; this is likely to be a reflection of slight accidents being cleared more quickly than those involving more serious injury (Table A1.2). Table A1.3 includes all OTS road user injury severity classifications (uninjured to fatal). In the OTS database the most common road users are car occupants who are often not injured; these cases do not appear in STATS19.
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Table A1.4: Number of vehicles within the OTS database
Cars were the over-riding vehicle type examined by the OTS teams, followed by light goods vehicles (LGVs) and heavy goods vehicles (HGVs) (see Table A1.4). Table A1.5 details the number of pedestrians who were involved in accidents which were attended by the OTS team.
Table A1.5: Number of pedestrians within the OTS database
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Table A1.6: Accidents by accident type and type of vehicle involved
Table A1.6 describes the number of accidents by vehicle type involvement. The largest group of accidents involved only two cars (n = 848) followed by single-car accidents (n = 816). The number of pedestrians shown in Table A1.5 differs from those detailed in Table A1.6 due to a number of accidents that involved either more than one pedestrian or more than one vehicle. |
Table A1.7: Number of accidents by police severity and road classification
Table A1.7 breaks down the total number of accidents attended in Phase 1and Phase 2 by the police recorded injury severity and road type. The greatest number of accidents attended occurred on A-class roads (37% of accidents attended). ‘A’ roads also had the greatest number of fatal or serious accidents. |
Figure A1.1: Time of collision
Figure A1.1 displays the distribution and actual number of accidents attended by the OTS teams by time of day. The greatest numbers of accidents were attended between 17:00 and 18:00, which is reflective of the evening rush-hour. |
Figure A1.2: Response times
Figure A1.2 displays the combined response times for the two research teams; the majority (53%) of accidents were attended within 20 minutes of the accident. |
Table A1.8: Number of accidents by collision type
In Phase 2, a description was added to the database in order to allow accidents to be grouped by type. Phase 1 cases were enhanced to include this categorisation too. Table A1.8 breaks down the 3,024 accidents within the OTS Phase 2 database by their collision type and sample area. Figure A1.3 gives a graphical representation of these results. |
Figure A1.3: Number of accidents by collision type
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It is interesting to note the different distributions of accident types within the two sample regions. This may be a reflection of the geographical make-up of the two areas, with the Nottingham area covering a more urban region. Most notably, the accident types which differ greatly between the areas are overtaking, crossing (no turns) and pedestrians crossing the road. |
Table A1.9: Accident causation
Table A1.9 shows a break down of the 3,024 cases in Phase 1 and Phase 2 by the precipitating factors. The most common precipitating factor was loss of control of vehicle, followed by failed to give way. |
Table A1.10: Contributory factors (driver/riders only)
Table A1.10 details the contributory factors for all drivers and riders in the OTS database using the Contributory Factors 2005 coding system. Each vehicle in the OTS database is assigned a pre-impact movement code, which describes the intended movement of the vehicle prior to impact. Table A1.11 cross-tabulates these pre-impact movements by vehicle type.
Table A1.11: Vehicle pre-impact movement by vehicle type
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Table A1.12: Human-level interactions
Table A1.12 details the number of interactions assigned to humans in the OTS database. The most frequent interaction type was conflict, followed by perception. |
Table A1.13: Humans by age band and road user type
Table A1.13 breaks down the road users in charge of the vehicle by their age. |
Table A1.14: Injury status by road user type
Table A1.14 details the number and type of road users and cross tabulates these against whether or not they were injured.
These tabulation and figures give a snapshot of the type and nature of the data contained within the OTS Phase 1 and Phase 2 database |
