Advancing Speed Management Strategies with HSIP—2020

Saving Lives by Designing for Safe Speeds

KEEPING ALL ROAD USERS SAFE

In 2019, 26 percent of total traffic fatalities in the United States involved 

speeding.1 Struck by a car going 50 miles per hour (mph), a pedestrian is 

highly unlikely to survive. However, reducing the vehicle’s speed to 42 mph 

increases the pedestrian’s chances to 50 percent. Furthermore, if we can drop 

the speed to 16 mph, that pedestrian has a 90 percent chance of survival.2

Because higher speeds increase fatality rates, new approaches in speed 

management are needed to reduce roadway fatalities and increase safety for 

all road users. A key element of the Safe System Approach is road design that 

keeps speed at survivable levels if a crash occurs. Ultimately, the Safe System 

Approach aims to reduce fatalities on the Nation’s roadway system to zero.

Speed management is an approach to setting appropriate speed limits, 

reducing speeding, reducing or mitigating the impact of speeding-related 

crashes, and achieving safe mobility.3 The Highway Safety Improvement 

Program (HSIP) can help fund proven speed management countermeasures.

71% of HSIP funds were used for 

162 speed management projects 

that converted existing intersection 

types to roundabouts. 

There were an equal number (106) 

of speed management projects 

completed on urban and rural roads.

Approximately 75% of speed 

management projects were 

on roads owned by State 

Departments of Transportation.

1

 NHTSA "Traffic Safety Facts: Speeding" (October 2021), 1, https://bit.ly/3I26CHS. 2

 AAA Foundation for Traffic Safety, Impact Speed and a Pedestrian's Risk of Severe Injury or Death (September 2011), https://bit.ly/3oEgl02. 3

 FHWA, Research and Development: Speed Management (October 2020), https://bit.ly/3GUoVyy. 

HSIP in 2020

In 2020, States 

obligated more 

than $345 million 

in HSIP funds 

to 303 projects 

that help manage 

roadway speed.

This figure represents 

roughly 14% of the $2.4 

billion total HSIP funding.

Roadway reconfigurations—or “Road Diets”— 

typically convert four-lane roadways into 

three-lane roadways with a center twoway left turn lane. Reducing through-lanes 

calms traffic and helps vehicles travel at 

more consistent speeds. Road Diets are 

a proven safety countermeasure and can 

reduce crashes by as much as 47 percent.

For more information about Road Diets, visit https://safety.

fhwa.dot.gov/provencountermeasures/road_diets/.

38 ROAD DIETS

FHWA-SA-22-021

5 states used 30% or more of obligated 

HSIP funds for speed management: 

New Hampshire (64%), Minnesota (40%), 

Maine (33%), Nebraska (32%), and 

Massachusetts (30%).

This information comes from 2020 State HSIP reports. For individual reports, visit https://safety.fhwa.dot.gov/hsip/reports/.

States used HSIP funds 

for speed management projects.

 States with speed management projects
To find out how HSIP can help save lives in 

your community, contact your State DOT:

2020 HSIP-FUNDED 

SPEED MANAGEMENT

IMPROVEMENTS

• Auxiliary lanes—modify free-flow turn lanes

• Congestion detection/traffic 

monitoring system

• Curve-related warning signs and flashers

• Modify control—modifications to roundabout

• Modify control—no control to roundabout

• Modify control—traffic signal to roundabout

• Modify control—two-way stop to roundabout

• Radar speed signs

• Roadway narrowing (Road Diet, 

roadway reconfiguration)

• Speed detection/truck warning system

• Traffic calming

• Change speed limit

Proven Safety Countermeasure

Roundabouts

In a modern roundabout, approaching drivers yield 

to the vehicles already circulating. Roundabouts can 

replace traffic signals as well as two- or all-way stop 

controls on both urban and rural roads. They are 

especially effective tools to help drivers safely transition 

from high-speed environments to low-speed ones. 

Converting a two-way stop-controlled intersection to 

a roundabout can reduce fatal and injury crashes by 

HSIP in Action

Oregon

Congestion, crashes, stalled vehicles, work zones, and weather can 

suddenly or unexpectedly change roadway conditions. Variable speed 

limits (VSLs) improve safety by helping drivers be more responsive to 

changing road conditions. VSLs can improve visibility, give drivers more 

time to stop safely, and reduce impact forces if crashes do occur.4

In 2016, the Oregon Department of Transportation (ODOT) used HSIP 

funds to install VSLs on a on a 30-mile stretch of I-84 where two 

mountain ranges frequently cause microclimates. Fog, blowing snow, 

and ice compounded issues from the road's high volume of truck traffic, 

a speed limit increase the previous year, and its curvilinear alignment.

To address these challenging conditions on I-84, ODOT installed cameras 

as well as pavement, air temperature/relative humidity, and traffic sensors 

to collect critical roadway data. ODOT uses these data to reduce and set 

speed limits in real time. Signs over the travel lane display the current 

speed limit and warn drivers about ice or low-visibility conditions.5

For more on this project, visit https://bit.ly/3whM8Gd. Along I-84, ODOT combines VSL and changeable message signs (CMS) to 

as much as 82 percent.

For more on roundabouts, see https://safety.

fhwa.dot.gov/provencountermeasures/

roundabouts/.

LOW

45 VISIBILITY

alert drivers about variable weather conditions that 

require speed reduction.

4

 FHWA, Proven Safety Countermeasures: Variable Speed Limits, https://bit.ly/2ZVaMAR. 5

 Rudolph Price, I-84 Baker Valley Variable Speed Limit System (June 2017), https://slideplayer.com/slide/12256666/.

https://www.fhwa.dot.gov/

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