Last reviewed 26 November 2018
One of the biggest road safety hazards in towns and cities is the interaction between motor vehicles and vulnerable road users such as cyclists, motorcyclists and pedestrians, with the main problem being the lack of visibility by the driver of certain areas around the vehicle where vulnerable road users are prone to place themselves. In this article, Richard Smith looks at the devices that can be applied to goods vehicles to mitigate this risk.
One of the biggest road safety hazards in towns and cities is the interaction between motor vehicles and vulnerable road users such as cyclists, motorcyclists and pedestrians, which nationally make up 35% of all road accident casualties and 51% of deaths. Perhaps counterintuitively, in urban areas, only 1% of road accidents involving pedal cyclists are with goods vehicles over 3.5 tonnes, while 3% are between cyclists and pedestrians and 4% involve only a cyclist with no other party. Accidents between cyclists and cars account for 78% of the total. Unsurprisingly perhaps, the death rate in accidents between cyclists and larger goods vehicles is the highest of all the combinations (6%) so while the likelihood of such an accident may appear to be quite low, the perceived risk (calculated as likelihood x impact) is relatively high.
These are national statistics, the figures for London alone may be different.
The onus on reducing this risk bears heavily on goods vehicle operators and drivers, largely because they are the ones on whom legal controls can most easily be applied but possibly also because of a degree of “white-hat” bias (when things that are seen as virtuous are favoured over those that are not).
The nature of the hazard
It is a common occurrence for any vehicle that has stopped at a traffic light in a large city like London to be surrounded on all sides by bicycles and motorcycles and this makes moving off when the lights change to green an extremely slow and careful business fraught with the hazard of collision and adding to traffic delays. The situation becomes even worse when a vehicle is turning left, particularly when there is a bus lane or cycle lane on that side for then the driver is in the position of turning left from the right-hand lane across traffic going straight ahead. This is a stressful situation for all drivers but is much worse for those in large goods vehicles because of the greater restriction of vision to the rear and side.
As noted above, the preferred solution ignores the first rule of risk management and concentrates solely on mitigation by imposing certain standards on designers, operators and drivers of vehicles because, despite this being the most expensive and least certain of the practicable solutions, it is the only one that can be enforced effectively.
The source of the problem is identified as being the lack of visibility around the vehicle for the driver, with lack of sufficient warning of vehicle manoeuvres a second consideration. The first of these is tackled by the addition of extra devices to aid all-round vision and the second by the installation of warning signs and turn indicators. As a final mitigation, side guards are also fitted to prevent people being drawn under the vehicle.
All goods vehicles over 3.5 tonnes first registered after 1 April 1985 must comply with the requirements of EU directives in respect of the fitting of mirrors and, in particular, those first registered after 1 January 2000 must now be fitted with Class IV (wide angle) and Class V (close proximity) mirrors that provide not less than 95% and 85% of the field of vision at ground level respectively. Irrespective of the EU directives and the Construction and Use Regulations, goods vehicles over 3.5 tonnes used in London must have Class V and VI (front) mirrors fitted.
Cameras can be an effective means of covering areas that cannot be seen by line of sight even using mirrors, particularly at ground level and directly behind the vehicle. One sees many large goods vehicles carrying signs “If you can’t see my mirrors, I can’t see you” but in order to do that, a following vehicle has to be a very long distance behind, far longer than would be practicable in an urban situation. In this case, a camera can provide a view behind right up to the back of the vehicle.
In addition to blind-spot elimination through mirrors or other vision devices, there are other ways to alert both drivers and other road users to a potentially hazardous situation. Proximity sensors, similar to parking sensors, covering the relevant areas can be used to provide an audible and/or visual warning in the vehicle cab. One disadvantage with these might be that they will continually react when driving in close traffic and also at other times to roadside objects.
Rather than an in-cab warning of the presence of an object in the danger zone, an alternative is an external warning alerting other road users to an intended manoeuvre. Indicator lights are already required to be visible over a certain angle round the corners of the vehicle, but such a warning can be reinforced by the fitting of supplementary devices specially designed and positioned to warn other road users not to get too close to the vehicle.
Many goods vehicles already have signs on the back of the vehicle warning vulnerable road users of the hazards around the vehicle but if they were not fitted these can cheaply and simply be applied — although the effect may be limited.
Mirrors and cameras are both indirect vision devices; direct vision means what the driver can see from the driving position by clear line of sight without any device. Generally, drivers of large goods vehicles have little or no direct vision of the area immediately surrounding the vehicle because of the combination of the dimensions of the vehicle and the height of the driving position. It is therefore very easy for a pedestrian, cyclist or motorcyclist (or even a small car) to be very close to the vehicle without its driver being aware.
Direct vision aims to reduce this possibility by ensuring that the goods vehicle driver has direct visibility of the most critical area. Two overlapping horizontal zones are identified as being critical for direct vision and these relate to the two most common manoeuvre situations: moving off and turning left. For moving off, the driver needs to see a rectangular area between 0.3m and 5m directly to the front, extending for 2.2m beyond each side of the vehicle. For turning left, the relevant area is that between 0.3m and 3.8m to the left-hand side of the vehicle and from 0.5m in front of the vehicle for a distance of 10m back.
Within these horizontal zones, the driver must also be able to see enough of the vulnerable road user to attract attention; just the top of a head may not be sufficient. The vertical definition of the visibility zone is therefore between 0.93m and 1.87m above ground level. This range allows for sufficient of 95% of all adult vulnerable road users to be seen to at least some extent whether standing or seated on a bicycle. It should be noted that this may exclude children, but analysis shows that they are very rarely involved in these types of collision.
Direct Vision Standards
Direct Vision Standards (DVS) have been developed that award a star rating to different vehicles based on the physical measurement of glazed areas. This is intended to match closely with the likelihood of the driver being able to see a vulnerable road user in the critical areas identified above.
A number of design features may be involved in improving the direct vision of these areas:
lowering the bottom of the windscreen and side windows
redesigning the dashboard to remove from the field of vision
inserting windows in the lower half of the cab doors.
Advice for operators
At the present moment, it is only operators with vehicles working in London that have to be concerned with this and those with vehicles over 3.5 tonnes must already meet the requirements of the London Safer Lorry Scheme. They will, therefore, already be compliant with part of the requirement for the issue of a haulage permit if they want to continue to operate in London with a vehicle over 12 tonnes after 2020.
If the vehicle does not meet a minimum 1-star DVS rating (4-star if it will still be in use after 2024), they will also need to install additional technology:
a camera system and in-cab monitor showing the full length of the vehicle
a sensor system alerting the driver to the presence of a vulnerable road user at the front and nearside of the vehicle
audible warning of an intended left turn
external pictorial stickers and markings to warn vulnerable road users of hazards.