Public Works -Road Funding Programs

Why Use Sidewalk/Curb Bulb-Outs?

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The City of Colusa has a combined set of challenges to address at the intersections in its

older “grid” area of town:

1. Most of the old curbs are 12 inches tall or taller making the installation of ramps for improved accessibility difficult and expensive.

2. Most of the roads have a high crown at the center making the side slopes too high for proper accessibility by physically impaired people.

3. The curbs come out to a point in the intersection that reduces turning space and can be an obstruction for drivers who misgauge their turns.

4. Most of the older area of Colusa does not have any underground piping to take stormwater and other water running off that area. This brings on two key issues:

a. The City has had to use culvert pipes to accommodate the water flow in the gutters. The ends of those culverts create an added obstruction that further narrows the turning space and can lead to more problems if a driver turns too tightly.

b. The options are very limited for making changes to the gutters for the purpose of improving pedestrian access or improving the drive-ability of the intersections.

5. Many of the corners at the older intersections have stone monuments or other items like old hitching posts which help show the historic character of the area. These items are generally placed right behind the point of the curb line and would have to be removed or relocated in order make the curb line suitable for today’s intersection layout standards.

Use of the bulb-outs addresses all of the above issues by:

1. Channelizing and continuing the gutter flow under a grate system that can be removed by maintenance crews for cleaning should the need arise.

2. Allowing the channelized gutter to connect directly to culvert pipes crossing the road under the pavement.

3. Allowing the sidewalk ramps to skip over the gutters and match up to the roadway (whether high crowned or not) with less sloping.

4. Creating a longer uniform curve to the curb line that helps drivers properly gauge how sharply they can turn and;

5. Eliminating the culvert and curb obstructions in the intersections.