Motoring groups and safety campaigners expressed alarm at the disproportionate number of pedestrian fatalities across the 98-square-mile accident blackspot.
Motoring accidents claimed the lives of more people who were on foot in the area on the edges of Glasgow than the rest of Scotland, from Edinburgh upwards, and the central belt combined, in 2012.
Pedestrian rights campaigners responded by calling for more to be done to address the safety of people crossing roads on foot - particularly older people.
The Institute of Advanced Motorists said the concentration of such a number of deaths warranted further investigation.
Newly obtained statistics showed 18 pedestrians were knocked down and killed in 2012 in the area from Bridge of Weir, Renfrewshire, Uddingston and South Lanarkshire, to Hardgate, West Dunbartonshire, and East Kilbride, South Lanarkshire.
A total of 53 pedestrians were killed in road accidents in Scotland last year, according a map pinpointing the locations of each fatal collision
The zone equates to 0.003% of the size of Scotland, or about half that of the Isle of Arran.
Keith Irving, head of Living Streets Scotland, a charity that campaigns for pedestrians' rights, said: "We know from the latest census results that Glasgow, Inverclyde and West Dunbartonshire have among the lowest car ownership levels in Scotland. Older pedestrians and those in lower socio-economic groups are at greater risk of injury or fatality, which can sometimes account for clusters of incidents.
"Overall, Scotland has a poor pedestrian safety record that needs to be addressed, especially given the ageing population. We need investment to make all our towns and cities safe walking environments and the introduction and enforcement of proven measures such as slower traffic speeds, considerate parking and safe crossing points."
Although the cluster falls within one of the most densely populated parts of Scotland, the figure is still out of proportion with the number of people living there.
The whole of Greater Glasgow - an area measuring 142 sq miles that includes Glasgow and the seven local authorities that ring the city boundaries - is home to roughly 23% of Scotland's population.
However, official accident figures show a smaller area within it accounted for 34% of pedestrian deaths.
There were nine fatalities in Glasgow, including a 71-year-old man who was killed when he was struck by a bin lorry in the city centre in August and a 75-year-old woman knocked down near Partick train station in the west end in May.
Living Streets said it was also concerned about a "huge increase" in pedestrian road deaths after provisional Scottish Government statistics published in August appeared to show a significant rise, from 43 in 2011.
Finalised figures for 2012 are due to be published later this month.
Tim Shallcross, an expert at the Institute of Advanced Motoring, said: "Such a disproportionate rate of deaths is concerning and warrants further investigation. The authorities should be looking at the times when they happened and ages of the victims. Is it mostly children, and if so why is that? Or is it mainly happening late at night, and what can we put in place? It could be that were are seeing the effects of drink-drive campaigns taking hold so more people are leaving the car at home when they go out."
Research by the Scottish Office in the late 1990s estimated one in three pedestrians knocked down in Scotland had consumed alcohol, a figure that mirrors the findings of more recent studies in Ireland and the United States.
While the number of pedestrians killed in Scotland has fallen almost steadily since the mid-1990s, from a peak of 121 in 1995, they now make up a higher share of those killed than ever before - almost one in three of all road user fatalities last year, compared to about one in five between 2003 and 2011.