Avancé de béton

Nos professionnels municipaux semblent avoir à la bonne les ralentisseurs de vitesse de type avancé de béton (bulb-out, choker, etc).  A Gatineau, on a eu le cas récent de la rue Isabelle, mais j'en ai vu à Buckingham et ailleurs.

Ils sont efficaces, recommandés mais pas la panacée que nos dits porfessionnels semblent croire.  Selon le Département des transports américain (USDOT):

''Diverting the path of travel plus restricting the lanes (often called "chokers") usually consists of a series of midblock curb extensions, narrowing the street to two narrow lanes or one lane at selected points and forcing motorists to slow down to maneuver between them. Chokers or lateral shifts that create pinch points or reduce the number of lanes, which may be accomplished through the addition of landscaped islands or sidewalk bulb-outs, are intended for use only on local streets with low traffic volumes. Chokers may be used to simultaneously create a narrowed pedestrian crossing zone. Use of chokers should be carefully evaluated to avoid creating potential conflict zones between overtaking motorists and bicyclists''.
(le surlignage est de moi)

On me répondra que nous sommes au Québec et, société distingue oblige, nous ne sommes pas soumis aux autres autorités.  J'ai des dizaines (voir plus de 100) de documents sur le vélo et les aménagements routiers de par tout le monde, et je n'ai jamais vu une photo ou une recommandation contraire à l'extrait cité plus haut.  De plus, une simple recherche Google ou Wikipédia vous donnera ces autres extraits:

''The Pedestrian and Bicycle Information Center states that curb extensions must not encroach on travel lanes, bicycle lanes, or shoulders, and should not extend more than 1.8 m (6 ft) from the curb.  Some curb extensions are built with the bike lane passing through (making the extension an island, separated from the main sidewalk by a narrow bike lane).  Poorly designed curb extensions can pose a hazard to cyclists, as they force cyclists from their position at the road side (or in a roadside bike lane) into the narrowed gap. They can also damage vehicles if the curbs extend too close to traffic lanes.  Curb extensions have not been found to affect the speed of vehicle traffic''.

''A single traffic calming treatment may be inadequate to reduce speeds, especially if education and enforcement are absent from the mix. It's the cumulative effect of a host of traffic calming techniques that makes a difference. Key ingredients are on-street parking, narrow lanes, curb extensions, vertical elements (such as trees) and buildings close to the street''.

''Curb extensions are primarily a pedestrian safety measure rather than a speed deterrent measure. No known studies have proven that curb extensions alone reduce speeds. Curb extensions at intersections usually improve pedestrian visibility: the first part of a crossing when a pedestrian enters the roadway is the riskiest. Curb extensions slow motorists at a point of conflict by tightening the turning radius, which improves motorist right-of-way compliance. Anecdotally, practitioners report slower speeds and say that right-turning vehicles are more likely to slow down.
More importantly, curb extensions shorten the street crossing distance for pedestrians thereby reducing their exposure to motor vehicles. On arterial and collector roads, complaints about speeding are often complaints about pedestrian safety; curb extensions are one way to address this issue.
Additional considerations include mountable, vertical or barrier curbs''.

Bien sûr, personne ne mettra sa vie en jeu basé sur un article de Wikipédia, mais içi on réfère à des documents sérieux.


GAP