Wednesday, 28 September 2016

Second Hand Bikes East London

Here's a list of places to get serviced and checked (not stolen) second hand bikes in East London.

It's a departure from my usual subject matter because I'm helping out a friend :-)

I've put stars by the ones people have recommended to me based on experience.

Not in East London but possibly worth a look:

Sunday, 24 July 2016

STATS19 collision data - Overview

The database of police collision reports comes from a standard form called STATS19. This collects a range of data on the collision, vehicles involved, casualties and injuries. A selection of this information is published annually as a database (details such as registration numbers are recorded but not published).

The data is published as three separate lists of information (in .csv format):
  • 'Accidents' (collisions) lists out the individual collisions with a reference number and data relating to the incident.
  • Vehicles lists out the vehicles involved, the accident reference, vehicle reference, plus data relating to the vehicle.
  • Casualties lists out the casualties, the accident reference and data relating to the casualty.
Each collision will have one or more vehicles and may have several casualties.

The STATS20 form gives details of what information is meant to be recorded and how the various categories work (for instance: what constitutes a minor injury, or how the vehicle codes should be used).

In this post I've summarised what is contained in the publicly available data, with a focus on information relevant to pedestrian and cyclist safety.


The list of collisions includes the reference number 'Accident Index', the location (easting & northing) and date & time in addition to:
  • The Police Force and Local Authority
  • Number of vehicles involved
  • Number of casualties 
  • Speed limit
  • Roundabout / One way street / Dual carriageway / Single carriageway / Slip Road / Unknown 
  • If the collision was near a junction/pedestrian crossing and if so the type of junction/crossing.
  • Lighting, weather and road conditions/hazards
  • Urban/Rural area


For each vehicle we are given the Accident Index and vehicle reference (001, 002, etc). If there is only one vehicle linked to a collision that would be 001. Details of the vehicle are:
  • The vehicle type (more info) and whether it was towing, left hand drive.
  • Vehicle manoeuvre, for instance: reversing, turning left, changing lane to right, overtaking on nearside etc.
  • Vehicle location: Main carriageway, Bus lane, marked Cycle Lane (advisory or mandatory), separate Cycle Way, Footway. Note that there is no code for shared space area so this information is not recorded.
  • Information on whether the vehicle is entering a junction, at a junction, leaving a junction, entering a roundabout etc. 
  • Whether the vehicle skidded/overturned, whether it left the carriageway and whether it hit an object.
  • Point of impact: 0. Did not impact, 1. Front, 2. Back, 3. Offside, or 4. Nearside 
  • Age and sex of driver.
  • Journey purpose of driver: 1. Journey as part of work 2. Commuting to/from work 3. Taking pupil to/from school 4. Pupil riding to/from school 5+. Other/Not known 


Similarly to vehicles, the records start with the Accident Index and then a casualty reference. The first casualty associated with the collision is 001, then 002, 003, etc. Details of the casualty are given as follows:
  • The 'casualty type' classification (more info)
  • Casualty class: 1. Driver or rider 2. Vehicle or pillion passenger 3. Pedestrian. Another field records whether they were a Bus/Coach passenger.
  • The severity of the injury. Injuries are recorded as serious/slight by the police usually within a short time of the accident and are often not based on the results of medical examinations.
    • 1, Fatal
    • 2, Serious: Serious injuries are generally those that would send the casualty to A&E or where they're likely to require further medical treatment. This includes: Broken neck or back, Severe head injury, Loss of arm or leg (or part), Fracture, Concussion, Deep cuts and Injuries to casualties who die 30 or more days after the accident from injuries sustained in that accident. 
    • 3, Slight: Slight injuries are generally those which require first aid or require no medical attention and include Whiplash, Shallow cuts, Sprains and Bruising.
  • Vehicle reference number - this is the number of the vehicle they occupied, or for pedestrians the number of the vehicle which first hit them. 
  • Age and sex of casualty.
  • Pedestrian location: footway/verge, refuge/central reservation or carriageway.


The data can be filtered using any of these categories and then mapped. One or two of the categories can be used to determine the map marker shape and colour. Other data can be displayed when the user clicks on a data-point.

For instance the data could be filtered to show only cyclists and pedestrians injured in collisions involving cars, with round markers for pedestrians and square markers for cyclists with the following colours: (fatal, serious, minor) = (red, yellow, orange).

Please let me know in the comments below if you have any suggestions for maps which might provide insights or illustrate particular problems.

Sunday, 10 July 2016

STATS19 collision data - Vehicle and casualty categories

When the police record road traffic incidents they use various classifications to record details vehicles, casualties and injuries. This information is entered in to the STATS19 database which is published annually.

The STATS19 data can be found here. The details of how vehicles, casualties, injuries etc. should be classified is published on the STATS20 form.

Vehicle Classification

The vehicle classifications are shown below. The number on the left is the code stored in the police database for each category (for the detailed notes about classification refer to the STATS20 link above).

It should be noted that many vehicle types do not fit the classification well - construction industry diggers would be classified as agricultural vehicles and 'other' category contains refuse vehicles and a variety of construction lorries and equipment. As a result, the goods vehicles data significantly under-represents the lorries most often causing fatalities by as much as 10-15% for both refuse lorries and construction lorries (based on TfL data for London 2010-2014). Taken together this could mean around a fifth of lorry fatalities are recorded in the 'other' category.

  • 01  Pedal cycle - includes tricycles etc.
  • Motorcycles - 'motorcycle' includes mopeds, motor scooters and three wheeled motorcycles.
    • 02  Motorcycle 50cc and under
    • 03  Motorcycle over 50cc and up to 125cc
    • 04  Motorcycle over 125cc and up to 500cc
    • 05  Motorcycle over 500cc
    • 97  Motorcycle – unknown cc
    • 23  Electric motorcycle - includes all electrically powered motorcycles over 0.25 kW, whether or not they are also equipped with pedals.
  • 08  Taxi/Private hire car - any vehicle operating as a hackney carriage, regardless of construction.
  • 09  Car - includes three wheeled cars, estate cars, family vans/multi-people carriers, Land Rovers and similar four-wheel drive vehicles.
  • 10  Minibus (8 - 16 passenger seats)
  • 11  Bus or coach - defined as 17 or more passenger seats.
  • 16  Ridden horse
  • 17  Agricultural vehicle - includes construction vehicles such as mobile excavators and front dumpers, but not heavy plant.
  • 18  Tram/Light rail
  • Goods vehicles include tankers, HGV tractors travelling without their semi-trailers and articulated vehicles.
    • 19  Van/Goods vehicle 3.5 tonnes maximum gross weight (mgw) and under
    • 20  Goods vehicle over 3.5 tonnes and under 7.5 tonnes mgw - Sometimes referred to as Medium Goods Vehicles or Large Goods Vehicles. These vehicles are included in the CLOCS safety scheme.
    • 21  Goods vehicle 7.5 tonnes mgw and over - Heavy Goods Vehicles (HGVs), although sometimes this term is used to mean all vehicles over 3.5 tonnes.  These vehicles are included in the CLOCS safety scheme.
    • 98  Goods vehicle – unknown weight
  • 22 Mobility scooter
  • 90 Other vehicle -  Predominately the vehicles causing serious injuries and fatalities in this category are large vans, refuse vehicles, tipper lorries, cement lorries and skip lorries. However the category also includes ambulances, fire engines, motor caravans, and quad bikes, plus anything else which doesn't fit the other classifications.
In addition to the information released publicly, the police database includes information such as the registration number. This can be used by the DfT/TfL to determine the exact make & model of the vehicles in order to analyse the data in more detail (especially the 'other' categories).

'Casualty Type' Classification

The casualty classifications are shown below. The number on the left is the code stored in the police database for each category:

0 Pedestrian
1 Cyclist
2 Motorcycle 50cc and under rider or passenger
3 Motorcycle 125cc and under rider or passenger
4 Motorcycle over 125cc and up to 500cc rider or passenger
5 Motorcycle over 500cc rider or passenger
8 Taxi/Private hire car occupant
9 Car occupant
10 Minibus (8 - 16 passenger seats) occupant
11 Bus or coach occupant (17 or more pass seats)
16 Horse rider
17 Agricultural vehicle occupant
18 Tram occupant
19 Van / Goods vehicle (3.5 tonnes mgw or under) occupant
20 Goods vehicle (over 3.5t. and under 7.5t.) occupant
21 Goods vehicle (7.5 tonnes mgw and over) occupant
22 Mobility scooter rider
23 Electric motorcycle rider or passenger
90 Other vehicle occupant
97 Motorcycle - unknown cc rider or passenger
98 Goods vehicle (unknown weight) occupant