Kigali City plans to build roads using cobblestones, which is cheaper to use and has a longer life span compared with tarmac roads.
Cobblestones are also said to be more environmentally friendly as scientists say tarmac roads emit dangerous gases.
The National Institute for Occupational Safety and Health (NIOSH) said acute irritation in workers was from airborne and dermal exposures to asphalt fumes and aerosols.
The NIOSH scientists assessed the chemistry, health, and exposure data from studies done in animals and humans exposed to raw asphalt, paving and roofing asphalt fume condensates, and asphalt-based paints.
Rwanda Today has learnt that the city plans to make 300 kilometres of road from cobblestone, which could translate into a 50 per cent saving on construction costs but will also protect the population from the associated health hazards.
“Kigali City’s amended plan is to have 300 kilometres of road made from cobblestones and 500 kilometres made from tarmac,” said an architect of a leading road construction firm.
“The cobblestone roads are far cheaper than concrete asphalt roads,” said Bruno Rangira, communications officer at Kigali City.
It is estimated that five kilometres of cobblestone road can be constructed at the same cost of a one kilometre road made from asphalt concrete. It is estimated that constructing one kilometre of tarmac road in Rwanda costs more than $1.5 million due to the hilly nature of the country.
According to a civil engineer, making roads from cobblestones could reduce costs to less than $500,000 per kilometre as the material is locally sourced.