Page 50 - TransportationPlanUsetsGuide

Beaverton-Hillsdale Hwy at Oleson Road

As shown in Table 3.6, by far the most common contributing factor to crashes in Washington County in 2013 was follow-
ing too closely, representing 42% of crashes and 43% of injuries. Failure to yield was another common factor contribut-
ing to crashes and injuries. Looking at fatal crashes, however, drunk driving and speeding were the leading causes.

Table 3�6: Contributing Factors to Crashes in Washington County (2013)
Contributing Factor Count Percentage Fatal Injury
Speed too fast 546 7% 5 266
Failed to yield 1,260 16% 2 601
Passed stop sign 74 1% 1 47
Disregard traffic signal 378 5% 1 212
Drove left of center 116 2% 2 53
Improper overtaking 56 1% 1 21
Followed too closely 3,227 42% 1,489
Made improper turn 313 4% 73
Had been drinking 251 3% 6 127
Improper driving 385 5% 3 115
Mechanical defect 24 0% 10
Other 1,102 14% 1 450
Totals 7,732 100% 22 3,464
Source: 2013 Oregon Traffic Crash Summary. Note: Crashes with multiple contributing circumstances are counted in all applicable categories.
SPIS
Locations that are prone to a higher rate of crashes are tracked and categorized using the County’s Safety Priority Index
System (SPIS). SPIS is an effective problem identification tool for evaluating roadway intersections and segments with
higher-than-average crash histories. The SPIS score is based on a running three years of data tracking crash frequency,
crash rate, and crash severity at over 300 intersections along Washington County roadways. While SPIS alone may not
reveal the real problem or root cause of a high occurrence of crashes, it is nevertheless a useful tool for identifying and
evaluating recurring safety issues. The County has pursued safety fixes at a number of locations in response to SPIS
data. Figure 3-6 presents 2011-2013 SPIS locations for Washington County roadways.

40 PART 3: TRANSPORTATION MODAL ELEMENTS
Effective November 27, 2015 • Updated December, 15 2016