9/11/2019
ITD initiates efforts to make safety improvements to ID-47 and US-20 through the city of Ashton
ASHTON
– Following a speed study of traffic on US-20 through the city of Ashton, the
Idaho Transportation Department (ITD) is recommending several safety
improvements. This will include installing flashing yellow lights, school zone
signs and reducing speeds while school is in session.
ITD has already made
several safety improvements at the intersection of Idaho Highway 47 and US-20. ITD
crews have installed a flashing "stop ahead" warning sign, a flashing stop sign
and rumble strips to alert drivers approaching the intersection on ID-47.
ITD's engineering analysis for US-20 through Ashton has
determined the speed limit should only drop to 35 mph during transition times
for school. During the rest of the day, the speed will remain at 45 mph.
ITD must be consistent statewide
and ensure speed limits are set according to Idaho law.
In 2012, the Idaho Legislature
passed HB619 directing ITD and the Idaho Transportation
Board to set speed limits on state highways within city limits. The legislation says, in part, “In establishing speed limits within city limits,
ITD must do an investigation and base posted speeds on sound traffic
engineering safety standards.”
Nationwide, traffic analyses for
speed limits include the determination of the 85th percentile.
This means traffic data is collected to determine what speed the majority of
drivers are comfortable traveling.
"When speed limits are not set at the speed drivers are traveling, there is a greater chance for speed variance between vehicles," said ITD Eastern Idaho Engineering Manager Wade Allen. "Reducing the speed limit below
the 85th percentile speed can result in conditions that are
unsafe."
The US-20 speed study in Ashton
included a thorough analysis of crash rate, traffic volumes, road condition,
access points, number of lanes, bicycle/pedestrian use and roadside development
along US-20 through the city of Ashton.
ITD is committed to make
additional safety improvements to the intersection, including installing
flashing lights on speed limit reduction (65 mph to 45 mph) signs, and installing dynamic “Your Speed” signs for southbound traffic (northbound sign already exists).
ITD also has a future project to
add a signal light at the intersection of US-20 and ID-47, which is currently
scheduled for Fiscal Year 2023.
For more information, please click on the following links to learn more about how ITD sets speed limits and to see the ITD Speed Limit brochure.