Central reserve - a solution to congestion?

Version 2

    Congestion means pollution. Long stops, followed by fast driving, make driving look like "stop-and-go-and-stop-and ...". This gets people angry. Impatience on return affects the quality of the cohabitation, especially between pedestrian and car drivers. Low-Emission Zones (LEZ) or High-Safety Zones have different layouts. This article presents a potential solution - the central reserve for pedestrians - that clears congestion by switching from a 50 km/h/ protected crossings situation, to a 30 km/h free crossing concept.


    The principle of "slow flow", within a 30 km/h zone, is generally perceived as applicable on low volume roads only, or residential areas. But as the Swiss example of Köniz suggests, it is possible to obtain significant results when implementing this concept on a busy street, even in the city core.


    In Köniz, the "Schwarzenburgstrasse" conversion showed at the same time that it is possible to :

    1. Reduce actual speeds
    2. Keep an identical traffic flow
    3. Increase public space dedicated to soft modes.


    But how is this accomplished?

    The goal of this "slow flow" project, implemented on the busiest street of the city (with high volumes of cars, pedestrians and buses) was to simultaneously reduce "obstacles" and "actual speeds" :


    • On a stretch of about 300m, larger space was allocated to pedestrians, by reducing the number of traffic lanes (4 to 2), by enlarging both sidewalks, and by adding a central reserve for pedestrians;
    • Posted speed limit went from 50 km/h to 30 km/h;
    • Fully protected crosswalks (lights) were removed and replaced by open-crossing opportunities on the whole section;
    • Traffic flow remained constant at 16,000 vehicles per day.




    The new environment benefits are significant to pedestrians and car drivers as well. Congestion was reduced even though cars are moving slowly, their travel time through the zone is identical (or smaller). This is due to the removal of long stops, which have been replaced by a fewer and shorter yielding to pedestrian situations. Speed is not only low, it is constant, which decreases the stop-and-go type of driving (0 to 50 / 50 to 0).


    Drivers pay more attention to pedestrians (60% after compared to 9% before: figure below), who are now crossing faster, without waiting for a crosswalk light to turn green, and according their own line of desire. The presence of a central refuge gives the opportunity to cross in a two-stage sequence, allowing more vulnerable pedestrian to perform an easier crossing, looking at only one direction at a time, with resting opportunity from the fairly wide and protected reserve.


    koniz_drivers looking.jpg


    As it's not possible to get everything perfect, the removal of protected crossings might create anxiety amongst the mobility impaired.

    But it is an applied example of solutions aimed at soft modes that also benefits, by extent, to car drivers.


    Other Swiss and German cities have similar models. What do you think of it?