For many years, the City of Kigali and its partners have been focusing on constructing 2x2-lane boulevards and the resurfacing of new roads, with the aim of distributing traffic across the city and facilitating access to an increasing number of neighbourhoods. In addition, the construction of sidewalks along road infrastructures has been systematised; and priority is being given to pedestrian’s crossings.

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These choices have proved judicious in terms of the efficiency of public spending – economically (residents can move around more easily, property owners benefit from increased property value, and economic agents can interact more within the city), and socially (walking in public space is perfectly legitimate).

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However, with the rapid growth in the number of vehicles in the city, the development of the road network is facing a classic problem: congestion at intersections.

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This issue can be addressed by implementing best practices in traffic management and taking action at various levels, such as establishing clear rules, developing appropriate responses to congested intersections, adopting a metropolitan approach to traffic management, and accelerating the development of public transport.

Who has priority at intersections?

At intersections with traffic lights, or police officers controlling the flow of traffic, the rules are straightforward. But what about when there are no traffic lights or police officers? Do drivers really know who has the right of way? The 2002 Presidential Decree Regulating General Traffic Police and Road Traffic sets out the following principles: at an intersection between two paved roads where there are no signs, "all drivers are required to give way to vehicles coming from their right” (Article 15), and when approaching a roundabout, "they must give way to vehicles already in the roundabout” (Article 16).

These two basic rules are designed to prevent accidents and improve traffic flow, but they are not applied on the streets of Kigali. This is particularly problematic at roundabouts, which can easily become blocked during rush hours. These roundabouts could accommodate up to 3,000 vehicles per hour, if their design was improved and systematic "priority to the left” was introduced.

In addition, road markings could help to make intersections with ‘give way’ or ‘stop’ signs more fluid. Often, vehicles do not stop in the correct place. Drivers often drive over the unmarked stop line, which reduces the flow of traffic in the priority lane.

Some of these junctions experience enough traffic to justify the installation of traffic lights to avoid long queues, but unfortunately this traffic management tool is underused in Kigali. The programming of traffic lights is generally far from optimal, and as a result, the Traffic Police prefer to turn them off. However, they can increase the capacity of intersections by up to 4,500 vehicles per hour, as was recently demonstrated at Gishushu, with the installation of pre-selection lanes.

At particularly busy junctions, traffic lights can be used to prioritise pedestrians and public transport. Intelligent traffic light systems can give buses a window of opportunity to pass through the junction with minimum impact on other traffic.

Adopting this type of system, coupled with dedicated approach lanes (often called "queue jumpers”), would make public transport much more competitive with motorbike taxis and ease the flow of traffic.

The author, based in Kigali, is the Director of International Operations at Transitec Consulting Engineers, an independent engineering consultancy firm specialized in urban mobility.