Vehicle data can provide vital evidence for forensic investigations but, in more complex cases, additional information is required to verify and better understand the full picture. In-depth analysis of the contributory factors required investigators to explore the behaviour of the driver, to examine the vehicle and to consider the potential effect ADAS systems could have had on the outcome had they been fitted.
Nature of the Incident
To support the Fatal Accident Inquiry into the death of six people, as a result of a bin lorry mounting a pavement and colliding with a number of pedestrians, after the driver of the lorry fainted at the wheel in Glasgow city centre in December 2014.
TRL was instructed by the Crown Office and Procurator Fiscal Service, Scotland to provide expert evidence on:
Vehicle Regulation & Advanced Driver Assistance System (ADAS) Technologies
TRL provided information on Advanced Emergency Braking Systems (AEBS) and Lane Departure Warning (LDW) systems in terms of:
- their intended functionality;
- the safety benefits they may provide, and;
- the Regulatory situation with respect to these systems.
TRL was also asked to comment on what influence these systems may have had, if any, had they been fitted on this particular vehicle in these circumstances.
An appraisal of the following was undertaken:
- To explore how people within a vehicle tend to respond to an accident as it is unfolding and in particular, if a driver has become incapacitated;
- Whether, in this event, the reaction of the two passengers was one that might have been anticipated of them;
- Whether it may have been anticipated the passengers could have undertaken another course of action (for example, trying to grab the steering wheel or operate the handbrake) and what possible consequences – positive or negative – that alternative course of action may have had;
- Whether there was any training, either available in the market or that could be created, that could successfully train passengers in a large/heavy vehicle, to react in a manner which could assist in the event that a driver becomes incapacitated;
- If an internal safety device, such as an alarm button that a passenger can depress to either mechanically bring the vehicle to a halt, or to emit an external alarm sound, was to be fitted would it be anticipated that passengers would, in the event of an emergency, react to activate this, or would, for example, their “self-preservation” reaction be likely to override this.
The involved vehicle was examined in order to provide comment on the appropriateness of the design of the vehicle’s cab. Of particular interest was the fitment of a metal rail that separated the cab into crew and driver areas, with a specific instruction to highlight any safety concerns or benefits that fitment may bring.
A technical report relating to vehicle safety devices that could prevent a vehicle, with an unconscious driver, from being allowed to continue uncontrolled was prepared.
Assessment was made of devices utilised within the Rail, Marine, Horticultural and Mining industries, to determine the technologies used and whether they have potential to be utilised within the Road Transport Sector.
TRL Expert Witness View
Vehicle Regulation & ADAS Technologies
The expert report addressed the technical parameters of the AEB and LDW systems, including their limitations and how driver actions can influence their operation.
Discussion was offered regarding the phased introduction for AEB and LDW systems based on new models (types) or new approvals, however due to the age of the incident vehicle it was not of an age where there was a requirement for mandatory fitment. In addition to the vehicle’s age, TRL established that ‘special purpose vehicles’ defined in the EC Framework Directive as “a vehicle intended to perform a function which requires special body arrangements and/or equipment…” are likely to include refuse trucks and, if so, categorised vehicles of this type are likely to be exempt from the EC requirements to fit AEB and LDW systems.
Our Expert concluded, through consideration of the circumstances around the actions of the two passengers in this event, that they were experiencing a period of immediate trauma and of fear of personal harm. Both crew members described what was ostensibly a normal working day; on a set ‘collection round’, with nothing untoward occurring which unduly interrupted their work. They described how there was no apparent hint of the driver becoming unwell and that he had had no warning of his collapse.
The crew members would not have foreseen that the event would be anything other than of short duration and not protracted to around 19 seconds. It was apparent that what might have been actioned by them in 19 seconds does not hold merit for consideration, as from the outset they were not expected to have indication of the event duration.
Due to the immediacy of substantial collision with the building line and the associated ‘dread risk’, following initial failed attempts to rouse the driver, self-preservation considerations by the crew members seemed a natural reaction to their situation.
Both crew members detailed thoughts or actions they might have tried, but for want of knowledge of the vehicle’s controls. They both described how the driver was positioned, hampering ready access to the steering and controls in any event.
Had the vehicle been fitted with a form of emergency switch designed to disable the vehicle that could have been operated by either passenger, the event might not necessarily have been entirely averted, but the consequences and duration would most probably have been mitigated.
The driver area of the cab consisted of standard DAF controls that were positioned around the driver in an ergonomic fashion. The position of the controls, and of the driver, restricted access by other crew members or vehicle passengers to them. It is standard with DAF vehicles, and most LGVs, that the parking brake control is to the left of the driver, therefore accessible to the crew members had they been trained, or aware of its purpose.
When the crew members were seated, with seat belts fastened, it would in theory have been just possible to apply the parking brake, but this required the crew member to be at full arm stretch and leaning fully forward against the seat belt. This is something that in a dynamic collision situation is considered counterintuitive.
The barrier provided the crew with a safe method of access when entering and exiting the vehicle; this was a repetitive task for the crew, in line with the primary purpose of the vehicle, and met with Health and Safety Executive Guidance, HSG136. It also provided the crew, when seated, with a grab handle.
The fitment of the barrier did enable the vehicle and its crew to operate safely. It was fit for purpose and enabled the crew to enter/exit the vehicle safely, preventing the crew from falling when moving within the vehicle.
Driver Safety Devices that are in use within other industries utilise methods or technologies that could not be incorporated within a vehicle travelling on roads. It was identified that the driver of a road vehicle is more dynamic whilst a vehicle is moving, using their hands and feet for multiple operations, and the incorporation of a safety device directly transferred from another industry could adversely affect the driver’s ability to safely control the vehicle in normal driving.
It was established that for multiple occupancy LGVs there is the possibility of incorporating an emergency brake switch, which could be retrofitted, along with introducing crew awareness training.
Experts from TRL presented live evidence to the Fatal Accident Inquiry presided over by Sheriff John Beckett QC.
TRL Principal Consultant Mark Hill advised that whilst the whole event lasted for 19 seconds, the time interval between the first deviation of the lorry to its first collision with the building line was 5 seconds. It would take some reaction time for the crew to process that something so unexpected was happening and to decide how they should react to it. Mr Hill considered that they had little more than 2 seconds within which to take any action.
Phil Balderstone, a Vehicle Examination Consultant at TRL, told the Inquiry that whilst it may be physically possible to reach and operate the secondary brake from the crew position with the vehicle at rest and with the seat belt on, that in practice the crew would have had to remove their seat belt and perform an awkward manoeuvre as the lorry pursued its uncontrolled course at speed. An innate instinct for survival would likely have directed the crew member away from doing so.
Mr Balderstone explained that the secondary brake is not connected to the systems which cause application of the service brake (the driver’s footbrake) to activate braking lights. The secondary brake does not have the ABS anti‑lock braking system which features on the service brake. Therefore, if the secondary brake was activated, the consequences would be unpredictable. It would have some slowing effect, but it may have caused the vehicle to skid with potential for the lorry to become uncontrollable.
Mr Hill explained further that it was possible that the lorry would have skidded further along the pavement. If that had happened, there could have been even more casualties. The change of course which removed the lorry from the pavement probably prevented there being an even greater number of casualties.
Both TRL experts considered mechanisms used within other industries and machinery to fulfil safe operation of the vehicle in the event of driver inattention. In their opinion, technologies used in other industries could not be transferred due to the comparative complexity of driving a road vehicle.
The TRL experts addressed the manual emergency brake switches that could potentially be engineered to minimise the risk of accidental application. They could be designed so as to apply the brakes progressively, to disable the engine and illuminate warning lights.
Consideration was made of a crew-activated emergency stop button which may have mitigated the consequences. Mr Hill expressed concern that such a device would carry a potential for inappropriate activation, where crew members potentially made well-intentioned misjudgements which could cause accidents with serious consequences.
Future technologies, including AEBS that incorporates protection devices for vulnerable road users, were also discussed by our experts.
In his summary, Sheriff Beckett QC made three recommendations linked directly to the expert evidence provided by TRL experts, the recommendations being:
Glasgow City Council should provide its refuse collection operators with some basic training to familiarise them with the steering and braking mechanisms of the vehicles in which they work.
Local Authorities and any other organisations which collect refuse, when sourcing and purchasing refuse collection vehicles which are large goods vehicles, should seek to have AEBS fitted to those vehicles wherever it is reasonably practicable to do so.
Local Authorities and any other organisations which collect refuse, and which currently have large goods vehicles without AEBS but to which AEBS could be retrofitted, should explore the possibility of retrofitting with the respective manufacturer.
 As direct result of TRL evidence at the FAI, Vision Techniques have developed Stop-Safe, as a system that can be retrofitted, and enables crew members to safely stop a “runaway” vehicle http://www.vision-techniques.com/stopsafe/case-study.