Page 26 - TransportationPlanUsetsGuide

GENERAL POLICIES
Safety
Transportation safety is a complex subject due to a variety of interacting factors. Road conditions, weather,
driver ability and vehicle type are just some of the factors that come into play when considering the safety of
a particular situation or location. Predictive models are available, along with anecdotal knowledge and expe-
rience with similar conditions. Traffic volumes, crash data, and citizen observations are just some of the ways
that staff can analyze locations and corridors to determine what type of improvements or changes to trans-
portation infrastructure would enhance safety. Each situation and location is unique, requiring engineering
analysis and professional judgement. This section is intended to provide a broad explanation of safety trends
and considerations for planning purposes.

In Washington County, new road construction, and the ongoing maintenance of the existing transportation
system, uses modern techniques, industry standards, and best management practices. In addition, an active
presence by law enforcement personnel reinforces the rules of the road. These roads are still subject to trav-
eler behavior factors such as speeding, following too closely, drunk driving and walking or bicycling without
appropriate visibility gear. Non-behavior factors may also play a role.

Tens of thousands of vehicles traverse Washington County roads on a daily basis and the vast majority of
ADOPTED TEXT those trips are without incident. However, there are some locations that tend to have an increased rate of
crashes. Metro’s State of Safety 2011 Report reveals that in 2007 through 2009, urban Washington County
had the lowest rate of injuring crashes per capita, the lowest rate of fatal or incapacitating crashes per
capita, and the lowest rate of fatal or incapacitating crashes per vehicle miles travelled, compared to urban
Clackamas County, the City of Portland, and east Multnomah County. Looking a trends over time, crash rates
2
for all modes (except motorcycles) are continuing to decline locally, regionally and nationally, after peaking in
the 1990s.

Safety initiatives in the region, including various Safe Routes to School programs and Portland’s High Crash
Corridor program, typically dissect transportation safety into three or more components within which action
may be taken. These are known as the three “E’s”:

• Engineering - Physical enhancements to improve safety on a transportation facility;
• Enforcement - Partnering with law enforcement to identify and reduce violations of traffic laws;
and
• Education - Helping people understand the rules of the road and how to walk, bike or drive safely.

Some Safe Routes to School programs have added other “E’s” – encouragement, evaluation, and equity –
that are useful tools in the broader context of transportation safety.

Evaluation is a particularly important function that Washington County undertakes. The Safety Priority Index
System (SPIS) List is the primary tool for identify intersections where crashes have been occurring frequently.
SPIS, originally developed in 1986 by ODOT, assigns intersections a score based on crash frequency (total
number of crashes), crash rate (number of crashes per entering vehicles) and crash severity (number of
crashes involving injuries or fatalities), over a three-year period. Intersections with high SPIS scores may or
may not have cost-effective or feasible remedies to reduce the frequency or severity of crashes, but the SPIS
tool is effective in helping identify safety issues in a strategic fashion.
2 Metro State of Safety 2011 Report, p 14, Metro

16 PART 2: GENERAL TRANSPORTATION POLICIES FOR WASHINGTON COUNTY
Effective November 27, 2015 • Updated December, 15 2016