Such growths have to be trimmed immediately to keep the roads clear. In forested areas, trees start to grow branches that can be hit by passing lorries - especially in severe wind conditions where the branches bend a great deal more than they otherwise might. A fractal road maintenance system would be integrated with sensors and tooling to permit them to trim plants and trees that infringe the roadway spaces. In autumn, there is danger of falling leaves building up on the roads and causing it to become slippery. Fractal robots can once again clean such rubbish off the roadway and perhaps burn some of it to generate power to move the machine along.
Plants are good decorating elements that can mitigate the effects of traffic and congested roads.
They are frequently used as barriers to shield out visibility into residential areas. Fractal robots could in theory erect millions of dust bin sized plant pots and barrier structures on our streets to green up the roads and make them more pleasant to look at and drive down. Even busy high streets could be changed with this approach.