Vehicles striking pedestrians or overturning, falls from cabs and lorry beds; the list of the most common workplace transport accidents is the same on construction sites as in the depots and factories that featured in the first three articles in our series. The causes are the same too: poor driver visibility, unsafe manoeuvres such as reversing and poor segregation of people and wheeled machines.

Where construction differs is that the normal risks are compounded by a mixture of uneven surfaces, changing layout and a cast of characters, many of them self-employed, that varies throughout the build process. These shifting risks go some way to explaining why transport accidents account for around 15 deaths and 300 injuries every year on construction sites.

Among the many regulations that should influence the safe use of site transport in construction, from the Management of Health and Safety at Work Regulations 1999 to the Lifting Operations and Lifting Equipment Regulations, it is the Construction Design and Management Regulations (CDM) 1994 and the associated Construction Health Safety and Welfare (CHSW) Regulations that set the pace.

The dutyholders in any project - clients, designers, principal contractors and the planning supervisor (soon to be renamed the CDM coordinator in the Regulations' new iteration next year - see CDM 2007: the new rules) - all have safety responsibilities that extend to workplace transport. Their efforts to predict and minimise transport risk associated with the project should be reflected in the pre-tender health and safety plan, the site traffic management plan and the final health and safety plan developed by the planning supervisor/CDM coordinator.

Marcus O'Connor, the HSE's lead on construction workplace transport, says the coordinator is critical: "They will be challenging in both directions. It's part of their challenging phase to ask, 'How are you going to move goods in and out? What are you specifying?'"

Though designers have an explicit duty to try and remove or reduce workplace transport risks under Regulation 13(2)(a) of the CDM, they often seem to make life more difficult for those realising their designs, with little thought about vehicle access and egress from the site or whether site traffic will be able to circulate safely when the buildings start going up. 

"Designers tend to think of the construction phase as the runt end of health and safety. It's left to the builder to sort out on site," says Jon Harper, an HSE inspector specialising in the construction sector. "Hopefully with the new CDM, the planning coordinator and the designer will work closely together to look at these issues using the coordinator's expertise in the construction realm."

The construction industry research body CIRIA publishes a guide for designers (CDM Regulations - Work Sector Guidance for Designers, available from www.ciria.org priced £50) which includes checklists of hazards associated with site transport and ways they can be accounted for in planning the construction phases (see box). A new edition reflecting the changes in CDM 2007 is due next April, but the transport advice should be unaffected.

Caring contractors

However important the safety roles of other dutyholders, it is often the principal contractor who is left to arrange the safe site operation. The HSE's guidance to inspectors is explicit on where the buck usually stops: "the majority of enforcement action will fall on the principal contractor."

Managing workplace transport risks on a construction site should involve applying the same hierarchy of controls as in any other workplace. First, the hazard should be avoided where practicable by removing the need for transport. "Where on a factory site that could involve installing a conveyor, on a construction site it might mean using a tower crane," says the head of the HSE's workplace transport team, Carol Grainger.

A crane will move materials delivered to the edge of a smaller site to wherever they are needed, cutting out the telehandlers and other on-site delivery vehicles, but it could be an expensive option.

Next in the hierarchy is substituting the hazard for a lesser one. Restricting deliveries to a compound at the edge of the site and only allowing competent trained drivers to move goods around may not reduce the number of vehicle movements but it will mean you remove drivers of large goods vehicles who are unfamiliar with the layout. On a project in northern Scotland, the developers Laing restricted deliveries to fixed hours and all loads had to be deposited in a holding area, then taken out into the site by telehandlers.

Harper admits the main drawback of this approach is that decanting deliveries to a holding area increases the risk of theft of valuable items. "The house-builders rather like to have single handling," he observes, "where a flat-bed truck goes into a close and delivers six kitchens at once straight through the front doors so they can be fitted straightaway."

The next level of control, and the one where the options multiply, is to reduce the extent of the risk from workplace transport by cutting the need for the most hazardous manoeuvres such as reversing and/or making sure vehicles are effectively segregated from pedestrians.

One-way systems are the obvious way to eliminate reversing. The HSE specialists point out that the "spider" layout of many housing developments, where cul-de-sacs radiate from access roads, makes reversing almost inevitable. If a developer can be persuaded to leave out the final house in each close until the end of the development, says Carol Grainger, the roads will remain open-ended and site transport can pass through until the last house closes the gap.

If unloading areas are set aside to handle all incoming materials, these too should be designed to allow vehicles to pass through without having to reverse or manoeuvre. Concentrating the unloading in one place also reduces the obstacles to site drivers' vision. Harper offers the example of a project involving several apartment blocks where deliveries were left all over the site. "The principal contractor took control of the situation and restricted unloading to one position, demarcated and separate from pedestrians, with a banksman on duty all the time. That worked fine," he says.

Where site traffic and pedestrians must share the same routes, they should be segregated with barriers, starting at site entrances, and traffic planning must ensure routes are wide enough to cater for vehicle and pedestrian paths and that vehicles will not pass too close to any excavations where they might weaken trench walls. Pedestrian crossing points must be planned in and clearly marked.

Grainger suggests a way to marshal traffic effectively on larger projects is to build the permanent roads that will service the finished development early on, noting that when the pavements are built, pedestrians should gravitate to them. "You also won't have vehicles arriving from unexpected directions," she adds.

Early road building is especially important on phased housing developments, O'Connor observes, where one phase will be sold off and occupied while others on the site are still under construction. "Boundary fences help there too," he adds.

Building roads, or even putting down the hardcore that will be their foundation, also has the benefit of providing a solid, relatively even surface for vehicles, removing some of the instability that is a common cause of "overturns" on sites.

Though the HSE's definition of workplace transport specifies vehicles being off the public highway, construction is one of the areas where the net is widened to include those making deliveries to the edges of smaller sites with no vehicle access. O'Connor says particular care is needed at these points since the risks extend to passing members of the public as well as employees. Harper agrees: "It's almost the worst situation. You have transport mixing with people who don't know what's going on."

He says it is worth discussing the options with the local authority and has seen a council agree to suspend the parking meters outside a site (in return for compensation for the lost revenue) to provide a dedicated unloading area. "There have even been some examples where the control of traffic lights has been handed over to contractors so they could get vehicles onto site safely," he notes. Insisting all deliveries take place outside rush hours is also sensible.

Falling down

Aside from the risks posed by lorries and delivery vehicles, those used inside building sites present their own particular hazards.

Rough-terrain variable-reach trucks - commonly known as telehandlers - are a case in point. Firstly, says Marcus O'Connor, they are unstable when heavily laden. He describes an incident on a Wolverhampton site where a telehandler was hoisting a roof truss onto a three-storey house and one of the site managers decided to move the vehicle back with the boom fully extended. It toppled over and smashed three cars and a lorry.

"It was only on a slight hill," he explains, "but with the boom extended the centre of balance moves significantly and any slight movement will make the boom bounce. Once that starts it could tip over one way or the other."

Secondly, since the loads can often obscure the driver's forward vision, they can be a danger to pedestrians even when they are not reversing. Last month, Cheshire-based demolition contractor J Routledge & Sons was convicted of failing to protect an employee who was struck and killed by a telehandler in Anglesey in January last year.

The HSE is pressing for the international standard on telehandlers (ISO DIS 1354) to be amended to require better visibility for drivers. "We don't think the standard is giving a high enough measure of control for the risk," says O'Connor.

Drivers of compact dumpers sit behind their loads and suffer from visibility problems when their skips are piled high. Grainger says that pedestrians also often underestimate the braking distance dumpers need, "because they are small and moving quite slowly".

On the level

Assessing site characteristics and ensuring vehicles have surfaces that are firm enough and even enough for their needs is also part of the planning process. Vehicles at risk of overturning are fitted with rollover protective structures (ROPS). "ROPS will provide good protection," says O'Connor, "but only if you are buckled in. If you roll over and you are not strapped in, it might not only not protect you but might even injure you more."

He says the principal contractor and/or the CDM coordinator need to ask the question "What kind of machinery do we need?" early on, and then make sure they get exactly what they specify.

"Suppliers tend to rent out equipment that is far more powerful than is needed, on the basis that the engines are less likely to wear if they are not used at full capacity," he observes. "But the smaller the machine is, the less of a visibility problem you have."

Jon Harper says that a little extra research into what machinery is available may pay dividends, citing a project where moving materials into a cul-de-sac was unavoidable: "They came across a special truck with a very tight turning circle, which avoided the need for reversing out."

Where reversing cannot be designed out and complete segregation of foot and vehicle traffic is not possible, a mixture of reversing aids such as mirrors, reversing alarms, closed-circuit TV cameras on the rear of vehicles and even radar-based presence-detection systems will help compensate for the driver's blind spot, but may still not be enough to remove the need for banksmen to guide them safely backwards.

There are hi-tech presence-warning systems where site pedestrians carry tags that trigger an alarm by radio frequency in any vehicle fitted with the system whenever the two get too close. These are expensive and rare at present but, as electronics prices fall, could feature increasingly on construction sites in years to come.

Good behaviour

Once all the physical measures to minimise and direct traffic movements on site are in place, site management will be tasked with making sure everyone is competent to follow procedures.  Delivery vehicles' arrival has to be monitored and they should know exactly where they are going and what they have to do to comply with the traffic management plan (see box).

Carol Grainger says principal contractors have to ensure all drivers on their sites are competent to handle any vehicle they are entrusted with. Research by the HSE's Health and Safety Laboratory found that this is not something anyone can take for granted: 32% of drivers surveyed on construction sites lacked formal training. HSE investigations of accidents involving site dumpers found similarly that one-third of drivers involved had no training and little experience.

All site workers, whoever actually employs them, should know what behaviour is expected of them around workplace transport. With so many migrant workers in construction, contractors may have to translate information or produce it in pictorial form to ensure nobody is left out.

Harper says that just providing the appropriate routing will not always guarantee compliance. "Guys who are old enough and mature enough to build houses will just walk down the centre of the road. It seems it's a bit sissy to walk behind the barriers."

Making an example of those who break the rules is not necessarily productive. "Companies find that asking people why they are doing something wrong and talking seriously to them is less likely to alienate them," he says.

Traffic planning

All the provisions for managing vehicles safely at site entry and across a compound that come from an initial site risk assessment should be summarised in the site traffic management plan required by the CDM.

"It's not just a map," says Marcus O'Connor. "It should notify what kind of kit is to be used. It should include lifting plans if necessary. It's specifying routes and crossing points for pedestrians and giving clear instructions on where the loading and unloading points are."

He says different site users should be given different degrees of detail from the plan: "Delivery drivers, for example, need to know the routes in and out, what they need to do once they get to site, where they should go to be safe while their vehicle is being loaded or unloaded."

The principal contractor should arrange full induction sessions for subcontrators before they start on site, covering all aspects of workplace transport rules.

The shifting geography of construction sites means that the traffic plan will need regular attention. "It's an organic thing," says O'Connor. "It needs to be updated on a weekly basis or when there is any site change that could alter a driver's field of vision. The results of not doing that can be catastrophic."

He says the updates should be shared with everyone concerned at safety rep and contractor meetings, providing new maps as necessary.