Surface Maintenance Program

There are 538 lane miles of roads in Multnomah County. The surfaces of these roads are maintained through chip seals, contract overlays and street sweeping.

Chip seals are a cost effective way to preserve rural asphalt roads, sealing the pavement and minimizing effects of aging.  The treatment process combines one or more layers of liquid asphalt and fine gravel that are bound together with a fog seal. 

For roads with higher traffic, the county hires contractors to do overlays. Private companies have the equipment for this paving work and can do it more efficiently. 

The county’s curb and gutter roads are swept once or twice a month depending on the season. In September, October and November, when there are a lot of leaves on the road, they are swept twice. 

Drainage Maintenance Program

Aside from surface treatments, maintenance teams manage drainage programs that keep catch basins, culverts and ditches clean.

Catch basins are curbside drains that collect surface runoff. The County drainage system contains over 1000 catch basins and they can easily fill with leaves, garbage, and silt. They are cleaned one or two times a year, depending on their need. 

Culverts are structures that transport storm and streamwater beneath roads. The county maintains over 1500 culverts and as they deteriorate over time, they are inspected and repaired based on condition. 

Ditches are cleaned in response to public and staff reports. Please use this form to report a drainage issue. 

Emergency Response

Our goal is to keep our roads open at all times. Road crews are on call 24/7 to respond to emergencies, from downed trees to traffic accidents to slides and washouts. Our emergency response follows best practices to ensure safety for the public and ourselves, and to protect our rivers and streams.

Right-of-Way Program

The right-of-way is county-owned property that runs alongside roads. A typical right-of-way is 60 feet wide and can consist of grass, gravel or dirt. Maintenance teams repair guardrail, remove litter and graffiti, and maintain road shoulders.

Vegetation Management

It’s common for shrubs and trees to grow in right-of ways. One of the maintenance program’s responsibilities is to keep roads free of plants that block drivers’ sight and to control invasive weeds. This work is done with careful attention to environmental impact.

Right-of-ways are mowed once a year and inmate work crews control overgrown brush. 

Signs and Striping

The county maintains 7,390 signs within the right-of-way. The majority of these signs are regulatory, like stop signs, but there are also advisory, guide and street signs. Maintenance teams change the signs every ten years and have a goal of cleaning them once a year.

On top of changing signs, maintenance teams also re-stripe every road in the county at least once a year. Roads with more traffic are striped twice a year.