Residents are quick to request traffic-calming measures to maintain safety and order in their areas however, Bertha Peters-Scheepers, spokesperson of Johannesburg Roads Agency (JRA) said this is not always the best option.
“Speed bumps are a major problem for emergency vehicles such as ambulances and fire engines,” said Peters-Scheepers.
“Apart from the major discomfort to ambulance passengers, they also delay response times substantially. This can be as much as 10 seconds per device. The longer wheel-base, stiff suspension, high vehicle weight, as well as the sensitive equipment and injured victims transported by these vehicles, requires drivers to slow almost to a stop to negotiate the devices safely.”
Peters-Scheepers said speed bumps are a very blunt instrument to use for traffic calming. “It is simply impossible to design a speed bump that is negotiable comfortably at a reasonable speed by all vehicles and which is not painful to the occupants,” she explained.
“Depending on the vehicle and the bump design, going over a bump at a higher speed may cause less discomfort than a lower speed.”
She went on to explain that speed bumps cause atmospheric pollution from the speeding up and slowing down of traffic between the bumps. They could also create additional traffic noise, depending on the type of vehicle. “The variability of the noise level as vehicles slow down before bumps and accelerate afterwards, can mean that the noise is more noticeable than before,” she said.
“Speed bumps can result in the relocation of the problem to adjacent streets especially in areas where the road network is designed in a grid pattern.”
