The police will need more speed traps!
The decision to lower speed limit in towns in Zambia to 40 km/h is interesting. I do understand why the authorities have made this decision, as lower speed limits reduce the chance of a crash and the severity of it. Driving at 40 km/h can save lives, or can it? A quick glance at the extensive literature on the subject suggests that lowering the speed limit will reduce maximum speeds and accidents, and even without affecting average speed and traffic flow significantly. However, compliance is key, and many studies have also concluded that motorists do not conform to speed limits they perceive as unreasonable for the prevailing conditions. The latter is important in Zambia! Just look at the four-lane Great East Road going out of Lusaka. At the last section, before the airport turn-off, the speed limit was recently lowered from 100 km/h to 60 km/h, despite the road being sheltered from developments. Judging from the number of motorists caught in the police’s speed trap the other day, many motorists do indeed perceive the new speed limit to be unreasonable for the prevailing conditions. The idea to lower the speed limit in towns to 40 km/h may have merit, but it will only work if it is being enforced, and right now there are not enough speed traps (or police officers to operate them) to go round.
Camilla Hebo Buus, Editor Zambia Weekly