SCOTLAND'S police chief has called for a change in the design of heavy goods vehicles after they were involved in a several road deaths.

Sir Stephen House has urged the government to act following the death of four pedestrians last year because of what senior police officers believe is a design fault in trucks.

Road safety experts say the drivers of some lorries simply cannot see people crossing roads directly in front of them, especially at lights in urban areas.

Sir Stephen said: "We have had an increase in pedestrian deaths and a spate of people being killed in collision with HGVs when, effectively, the lorry driver cannot see the person directly in front.

"That puts elderly people particularly at risk. Because if they are slower getting across the road and the driver has not seen them enter the pedestrian crossing they might be right in front of the lorry when the driver puts their foot on the accelerator."

"That is vehicle design. That is driven by commercial interests that you make the cab as high as possible so you can maximise the available space for carrying goods. It is not the safest for pedestrians.

"Some vehicles have changed their design for safety for pedestrians. HGVs have not done that yet. That is a market issue. That is a commercial pressure, which governments could do something about if they wished."

Sir Stephen in recent years has focused heavily on road policing, stressing that bad driving - not vehicle or road design issues - was the biggest cause of casualties.

Last year in Scotland there were more pedestrian road fatalities, 56, than homicides.

That represented a rise of 18, only partly explained by the one-off disaster when a bin lorry killed six in Glasgow in December 2014.

The bin lorry crash - and the four blindspot deaths - have highlighted the dangers of HGVs in urban areas.

Lorries only account for about two per cent of incidents - but 13 per cent of fatalities. More cyclists on the road - and a failure by the UK to match continental levels of cycle paths - means some in the industry fear things could get worse before they get better.

Kevin Clinton, head of road safety at the Royal Society for the Prevention of Accidents, said: "HGV design needs to be improved to make it easier for drivers to see pedestrians and pedal cyclists.

"A lot of attention has been put into improving mirrors and using sensors and cameras to help HGV drivers see what's around their vehicle, but a more fundamental approach of lowering the cab height and having see-through glass panels in the doors would significantly reduce the risk of pedestrians and cyclists being hit by these large vehicles."

New EU legislation will come in to place in 2020 allowing lorries to be a little longer, as long as they aren't any heavier.

Nigel Bates, of the Society of Motor Manufacturers and Traders, said this coming reform meant the industry was now looking to develop tapered noses that crumple and cut blindspots.

Mr Bates, who is a trucker and a cyclist, said: "We are fully aware of the problem and want to do something about it. But HGVs are complex and expensive vehicles and they take time to change.

"So in the meantime we are going to have to make more use of cameras and mirrors."

Christopher Snelling of the Freight Transport Association, stressed operators were eager to see changes too.

He stressed: "These are horrendous experiences for the people concerned but also for our drivers, some of whom never work again."

Chief Superintendent Iain Murray, Police Scotland's head of road policing, said: "It's important for drivers to check blind spots around, and in front of, the vehicle before moving off and it is also important that pedestrians remember that if they cannot see the driver of a vehicle it is unlikely that the driver will be able to see them."