SECTION 1

Introduction

• Summary

The first fatal road collision happened on the 25 of February, 1899, when Mr. Edwin Sewell was driving negligently and after he lost the control of his car and crashed, he and his passenger died from head injuries. Because of the breaking pressure of 20mph the wheels collapsed and this accident was considered to be the first fatal ever recorded, even with the low collection of data (Lavender, 2001).

The Collision Investigation Unit (CIU) (Appendix), is the department of the police force that has to examine the road traffic accident scenes. Collision investigators treat the scene of a road accident in the same way as other serious crimes. As much evidence as possible has to be collected from the collision scene, such as photographs, detailed diagrams, tyre marks and fixtures, in order to establish the cause of the accident and bring the investigation to an agreeable termination (Melling, 2007).

Year on year, the work of the CIUs is becoming less and less. According to statistics of the Department For Transport (DFT), drivers in Britain are driving more safely year on year, because fatal accidents keep dropping year on year. In the year of 2005 the annual deaths from road traffic accidents were 3,201 in contrast of the year of 2004 that Britain had 3,233 deaths from road collisions (Clarke et. al., 2005).

Another statistic comes up to show that the amount of road accidents is reducing year on year. In the year of 2003, Britain’s annual amount of collisions was 13,908. In the next year 13,879 collisions happened and in the year of 2005, 13,388 road collisions happened. Via the statistics, people drive more safely every year (Clarke et. al., 2005).

• Aims and Objectives

This study is going to investigate the current surveying methods that are used in road traffic accidents in Britain by the CIUs of the police force, the types of equipment that being used, the reliability of the equipment and when surveying methods have to be used to survey a collision (The Legal Requirements).

After the inspection of all of the above, in the conclusion there will be a brief review of what this submission was about and the points of high importance will be highlighted.

SECTION 2

Accident Investigation

2.1 The history of mapping the accident scene

The accident investigation courses began for the first time in 1970 in London in order to train Collision Investigators. At first, this system was operating on a low budget and it was easy to teach police officers to use that method. About 1992 Collision Investigators began to use the surveying equipment in their investigations, because this equipment has many advantages. After the accident, distances and angles were obtained and used for the production of a representation model. Moreover, after the examination of the road accident scene, references and summaries had to follow to cover the incident completely (Lavender, 2001).

Despite the fact that today Collision Investigators are able to use devices such as Total Stations or Scanners, the main three steps are still being followed. Firstly, to locate the data such as tyre marks, secondly, to collect as much data as possible and last but not least, to examine the collected data (Devon and Cornwall, 2003).

2.2 General view of an accident:

When a traffic accident occurs, the most known procedure is being carried out. Police have to attend to the accident scene as soon as possible in order to examine it. Police are being informed about the accident by the people who were involved in the accident, or if it is a fatal accident, by a passerby or a witness. If it is reported to the police that it is a fatal collision, automatically the Paramedics and the nearest Fire Brigade are notified. If the Police Force arrives earlier to the accident scene than the Paramedics, the police have to wait for them to come and take care of the injured people at first. The Fire Brigade is involved in the collision scene only if the injured persons are trapped in their vehicles in order to set them free from the debris of their vehicles, or if a fire breaks out from the big impact to put it out quickly for safety reasons and to prevent the evidence from being destroyed (Collision Analysis, 2007).

At the same time that the Paramedics and the Fire Brigade are dealing with the accident, the police force is guiding the traffic. When the Paramedics have done their best and collected the wounded people from the accident, the CIU has a clear runway to do its best too. The Fire Brigade stays at the scene to cooperate with the Investigation Unit if it needs to. The CIU starts to collect any parts of the cars that had been disconnected and at the same time the surveying equipment is being used. The Unit also, takes photographs of the tyre marks and if it is necessary, overview pictures captured from a helicopter to be kept in the record of the accident. CIU is doing the process very analytic, because despite the regular cause of a road accident is exciting the speed limit, it can be founded out that the road was not appropriate or suitable for driving, or any other cause. After the collection of evidence from the accident scene, the vehicles are moved away by a towing vehicle, but the work of the Collision Investigators is not over yet. The work is carried on to the Police Traffic Department and after the examination of the data taken by the surveying equipment, a summary has to be produced so as the Investigators cover the collision totally. In addition to the summary, a 3-D (Dimensional) picture has to be constructed on a computer, to be kept in the records for future examination (Collision Analysis, 2007).

Additionally, sometimes it is possible that the summary of the road accident investigation can be produced in 2-D (Dimensional), because the 2-D scanned area also allows the evidence to be shown clearly. The representation of the road accident with 2-D results or 3-D results depends on the complexity of the road collision (Melling, 2007)

2.3 Legal requirements of an accident:

According to the police officer of the Collision Investigation Unit of Warwickshire Police Department, Robert Melling, every accident scene has to be surveyed and mapped unless the head officer of the Unit feels that the evidence is so obvious that the accident can be classified by just using photographs of the scene. The average attendances and surveys of the Warwickshire CIU to road accidents are approximately 150 investigations per year. In a few words, Collision Investigators examine an accident only if it is complicated, such as pile ups accidents or if the evidence of the scene is not comprehensible to sort out the collision. CIUs might use Total Stations, 3-D (Dimensional) Laser Scanners, or photographic cameras.

SECTION 3

Current Surveying Technologies

3.1 Total Stations:

This section will look at the use of a surveying device called Total Station, in the examination of a road accident. The Total Station (Appendix) is a device that is used in recent surveying and provides measuring distances and angles without using a tape measurement. Everything happens electronically. Total Station integrates an electronic theodolite, an Electronic Distance Measurement (EDM) mechanism and a tripod, (Fialovszky, 1991). This device is connected to an external computer and all the data that is captured from it, is transferred to the computer in order to produce a map of the surveyed area through the software. Mostly, Total Station is based on trigonometry and the actual positions X, Y and Z from the control point (Collins 1972).

Total Station is basically a telescope with a cross in the middle, to mark the target. By the time the target is locked, the angle of rotation and the angle of inclination have to be noted. This telescope offers a digital read out of the angles and it is more accurate and less exposed to faults. Moreover, it is important to add that the read-out is nonstop so the angles can be measured at anytime. The other part of the total station is the EDM (Electronic Distance Measurement), that calculates the distance between the device and its target. The EDM forwards an infrared ray and it is echoed back to the component and the component employs instancing dimensions to analyse the space by the ray (Burnside, 1982). Collision Investigators use a Total Station instead of a tape measurement in their investigation, because of its accuracy and because they are able to review the accident scene at any time, throughout the data that was processed to the external computer.

On the other hand, the Total Station device has some drawbacks such as when the line of the sight is affected from a reflective point the data collection could be erroneous. This can affect the accuracy when an object is between the device and the target, for instance trees. Moreover, the time of the day can affect the collection of the data of a survey, because the Total Station cannot be elaborated at night time (Whyte and Paul, 1982)

Additionally, there are many models available in the market by manufacturers such as Leica, Nikon and Pentax. Leica’s TPS 2000 is the latest series of Total Stations that has very high accuracy at about +/- 2mm and weighs approximately 6 Kg. Also, TPS 2000 sere has an automatic target tracking and a Remote Control System (RCS), (Leica, 2007). Nikon’s latest model is DTM-801 Series has the same accuracy as the previous product with +/- 2mm accuracy. The distance measurement with a single prism is 2400 meters and has a visible range of over 100 meters (Nikon, 2007). Pentax’s latest instrument is R326EX, from the series of R300X, which is compensated on the Dual Axis and the measuring range with a single prism, is 3400 meters. Its battery life is for 6 hours and weights about 5.5 Kg (Pentax, 2007).

3.2 3-D Laser Scanning Systems:

3-D Laser Scanners (Appendix) have been designed with the aim of creating a 3-Dimensional model from the collected data. The laser is being reflected off by any surface and returns back to the instrument, therefore the scanner saves thousands of points per second, which permits a gigantic amount of data to be collected in just a few moments. The axis of the scanner is the values 0, 0, 0 and these points are the distances and the horizontal and vertical angles from the scanner. The 3-D value is being provided to the user when the distances and the vertical and horizontal angles are measured and throughout a computer the user can see the results as they are being downloaded immediately (Rw, 2002)

This mechanism enables the user to scan every single object in a small timing. It is mainly completed from a high definition camera, a laser security system, a target projector, a laboratory calibration and a stand. This device is connected to a laptop computer by a FireWire port and consequently the FireWire port provides faster downloading speed on the external computer. The most important benefit that some 3-D Laser Scanners have is the ability to retain the data without requiring any daylight, because it has its own light provided by the laser and this makes it to work in the same way with the same results even though being day or night. Furthermore, another advantage of the 3-D Laser Scanners is the ability that some devices have to scan the object and download it colorful on the computer even if it is night. Collision Investigators are able to scan the accident scene even though the accident was caused day or night with the same accuracy and other details (VibroDynamics, 2004)

In contrast, there are some drawbacks about the 3-D Laser Scanner. First of all it is very expensive to buy and use and in order to survey and map one scene such as road accident, it is better to do it with a regular product that provides almost the same results as the 3-D Laser Scanner. The second disadvantage is that the user needs many hours of training to learn how to use it properly (Schmiedl, 2007)

3-D Laser Scanners are created by companies like Riegl, Trimble, Leica and more. Riegl’s top product is the LMS-Z420i which it can scan 11000 points per second with fluctuated mirror and 8000 points at a high scanning rate with a rotating mirror. This device is protected from dust and it is water proof, because of a protection glass that is installed on the mechanism. The vertical scanning rate is 80^o and the horizontal is 360^o, with a distance maximum range of 1000 meters (Riegl, 2007). Trimble’s latest instrument is the Trimble GX 3D Scanner and it uses high-speed laser and video to capture vast amounts of points and data. GX 3D Scanner can collect 5000 point per second and its accuracy is +/-2mm, but that depends on the surface type and the distance. Also, it weighs 13 Kg and it cannot be operated under -20^oC and over 50^oC (Trimble, 2006). Leica’s HDS4500 (High Definition Survey) is also a high-quality product, because it has a scanning rate from 100,000 up to 500,000 points per second and it is able to scan the horizontal angle at 360^o and the vertical angle at 310^o. It weighs 26 Kg and it is the most expensive mechanism from all the mentioned above. It costs about £95,000 (Leica, 2007).

3.3 Photogrammetric Systems:

Photogrammetry is the science that obtains reliable measurements from photographs. A digital photogrammetric system can be defined as hardware and software device that produces photographs from digital imagery by using manual or automatic methods. The photogrammetric instrument (Appendix) that is famous and is being used not only from amateurs users, but also from professionals, is the 35mm device. Furthermore, metric and non-metric devices are the main types of cameras, but only the metric cameras can be used for purposes such as accident investigation. (Graham and Koh, 2002).

According to Meyer and Grumstrup (1978), there is a technique for making distance measuring from a single vertical photograph. In order to make a distance measurement from a vertical photograph, the real distance between two points on the picture, has to be known. For instance, a bridge that is being shown on the vertical photograph has real length 500 meters and it covers 0.5cm on the paper, the scale will be 1:1000 for the photograph and all the objects that are printed can be measured and the real dimensions can be calculated throughout some mathematic equations.

Companies for example Canon, Fuji and Nikon are operating the production of these devices and their objective is to make the newer product better that the last, so cameras are developed step by step. Canon’s most recent camera is the EOS 400D, which it offers a high definition analysis in order to capture more details of one object. Basically, Canon EOS 400D has 10.1 megapixels, the zooming system is manually set and it can reach a closer look of 5 times more than the normal view of an object (Canon, 2007). Fuji has a better product than Canon, the Fuji FinePix S5, with 12.3 megapixels, plus, if it is switched to the setting of high continues shooting, it is able to captures up to 3 frames per second and it has object detection technology, which allows the camera to detect one object automatically (Fuji, 2007). Nikon’s camera D200 has 10.2 megapixels and it can capture 5 frames per second. In addition to the D200 model, it has a USB 2.0 (Universal Serial Bus) connection high-speed and it costs approximately £1280 the entire device (Nikon.com, 2007).

Collision Investigation Units are using photographic equipment that is classified in the same category of the products mentioned above, because that photogrammetric technology has the latest improvements than the previous models and CIUs have to examine all the details that they are able to collect so the results of an investigation would be reliable as possible. The better the resolution the camera has, a higher quality image can be captured, but the regular camera resolution for surveys like Collision Investigations, has to be at least 5 megapixels or a little better. Moreover, a downward picture (Aerial Photography) of an area can be captured to make the mapping purposes simpler. This happens if the use of a helicopter is available (Melling, 2007).

SECTION 4

Conclusion

4.1 Review:

While a collision happens, onlookers think that the collision has been covered and the job of the CIUs, Paramedics and Fire Brigade is done by the time the crashed vehicles are collected by a towing vehicle. All that happens in the collision scene was the collection of the evidence and data. Collision Investigators have to examine the data and after the analysis, the results are produced and recorded.

By the time surveying methods are being involved in road collisions, surveys are being completed rapidly in comparison with the traditional style of examining an accident scene. As it was mentioned before, by the year 1992 CIUs have improved the procedure of surveying the road accident by engaging surveying equipment in their work and throughout this decision the examination of the accident is not only quicker than it was, but also it is more accurate and reliable.

4.2 Synopsis:

Briefly, the aims of this project were successfully achieved, by explaining the involvement of the CIUs in road collisions and the importance of the surveying equipment was also evaluated. Total Stations, 3D Laser Scanning Systems and Photogrammetric Systems have been deeply analyzed from the angle of surveying a road traffic accident. These technologies are effective because by using them, accuracy, reliability and quick procedure of any investigation can be brought to the surface.

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