0 1,000 2,000 3,000 4,000 5,000 6,000

2013 INTERSECTION FATALITIES

Signalized 3,338

Unsignalized 5,760

? Other/Unknown 235

Source: FARS, National Highway Traffic Safety Administration (2013). Available: http://safety.fhwa.dot.gov/intersection/resources/intsafestratbro/intersection_guide12.pdf

SIGNALIZED INTERSECTION SAFETY STRATEGIES

Intersection Safety 

Strategies

Second Edition

CATEGORY B: REDUCE 

INTERSECTION CONFLICTS 

THROUGH GEOMETRIC 

IMPROVEMENTS

lB1 – Provide/improve turn lane 

channelization

Where to use - Signalized intersections 

with a high frequency of rear-end collisions 

resulting from conflicts between: (1) vehicles turning and following vehicles; and (2) 

vehicles from downstream intersection crossing traffic lanes to enter turn lane. The 

channelization can also provide a pedestrian refuge area and reduce pedestrian 

crossing distance.

Keywords: channelization, right turn, left turn, turn lane, raised curb

lB2 – Improve geometry of pedestrian and bicycle facilities

Where to use - Signalized intersections with high frequencies of pedestrian and/or 

bicycle crashes and on routes serving schools or other generators of pedestrian and 

bicycle traffic. Measures can include curb radius reduction, curb extension, pedestrian 

refuge/raised median, and raised intersections.

Keywords: pedestrian, widen sidewalk at intersection, raised intersection

lB3 – Utilize innovative intersection geometry

Where to use - Signalized intersections with high levels of crashes on a leg where 

other low-cost strategies have not been successful or are not considered 

appropriate.

lB4 – Corridor access management - implement median closures

Where to use - Signalized intersections with patterns of crashes related to particular 

turning maneuvers where drivers have difficulties finding an acceptable gap in traffic.

Keywords: access points, access management

lB5 – Provide right-turn lanes at intersections 

Where to use - Signalized intersections with conflicts between right-turning vehicles 

and following vehicles, and significant right-turn volume along major road.

Keywords: access points

PED

SIG BIKE PED P

P E

SIG P

SIG P

CATEGORY C: IMPROVE 

SIGHT DISTANCE AT 

SIGNALIZED INTERSECTIONS

lC1 – Clear sight triangles

Where to use - Signalized intersections where 

there is a high frequency of crashes between 

vehicles turning right on red from one street 

and through vehicles on the other street or 

crashes involving left turning traffic where landscaped medians are present.

Keywords: triangle sight distance

lC2 – Increase positive turn lane offset

Where to use - Signalized intersections where there is a high number of crashes due 

to turning vehicles limiting the sight distance. Left-turning vehicles can limit the sight 

distance of left turning vehicles and opposing through vehicles. Right-turning vehicles 

can limit the sight distance of right-turning cross street traffic. 

Keywords: turn lane, offset, positive offset, left-turn lane, right-turn lane

SIG BIKE PED

SIG BIKE PED

For more information, please visit:

http://safety.fhwa.dot.gov

The original version of this brochure (FHWA-SA-08-008) was originally produced 

as a quick reference to all the strategies listed in NCHRP Report 500, Volume 5 

(Unsignalized) and Volume 12 (Signalized). This second edition has been revised and 

updated to reflect more timely information and experience available through the 

Crash Modification Factor (CMF) Clearinghouse.

Key to the Brochure

Costs:

Costs will also vary considerably and are affected by local conditions. Costs are ranked 

as: low, moderate, moderate to high, and high. The scale is meant to reflect costs 

relative to the other strategies described in the category (signalized or unsignalized).

lLow Cost Measure lModerate Cost Measure lHigh Cost Measure

 FHWA Proven Safety Countermeasure: 

More information about FHWA Proven Safety Countermeasures can be found at: 

http://safety.fhwa.dot.gov/provencountermeasures/

 FHWA Everyday Counts: 

Every Day Counts (EDC) is an effort led by FHWA in cooperation with American 

Association of State and Highway and Transportation Officials (AASHTO) to identify and 

rapidly deploy proven but underutilized innovations to shorten the project delivery 

process, enhance roadway safety, reduce congestion and improve environmental 

sustainability. See http://www.fhwa.dot.gov/everydaycounts/ for additional 

information.

Keywords:

Keywords have been provided for those countermeasures with a crash modification 

factor in the CMF Clearinghouse (http://www.cmfclearinghouse.org/). Some 

countermeasures may be found using a variety of search terms and the keywords 

provided are examples of those terms. For those countermeasures without keywords 

listed, their effectiveness may not have been studied or submitted to the CMF 

clearinghouse. 

P

E

SIGNALIZED COST

SAFETY CONCERN lLow lModerate lHigh

High frequency of right-angle crashes 

attributed to:

nearby driveways F2 F1

traffic from cross street A2, A3 E2

skewed intersection

poor sight distance A1, C1, G5 C2, G4 B3

drivers misjudging gaps A1

not enough gaps for drivers A1 A4, B4

driver unaware of intersection D1, D2, D5, D6 C2 B4

nighttime conditions D1, D2, D5

right turning vehicles hit from side A3, C1, G5 B1, G4

High frequency of rear-end crashes 

attributed to:

left turning vehicles hit from behind A1 B1 B3

left opposing vehicles hit from behind B1 B3

right turning vehicles hit from behind A3 B1, B5

standing water on roadway G1

vehicles unable to stop safely (skidding) G2

driver unaware of intersection D1, D2, D5 D3, D4, D8 D7

nighttime conditions D1, D2, D5 D4 D7

speed differentials of vehicles A4, E3

sudden stops A2, A3 A4, D3

High frequency of left-turn crashes 

attributed to:

left turn vehicles hit by opposing traffic A1, A3, A7, C1 B1, B4 B3

nighttime conditions D1, D2, D5

High frequency of sideswipe crashes 

attributed to:

vehicles within intersection A1 B1

High frequency of pedestrian/bicycle 

crashes:

on school routes or near generators of ped/

bike traffic A8 B2, E2

vehicle/bicycle sideswipes on approaches A9, G1

with left turning vehicles A1, A3 A9

Address overall safety issues:

violation of traffic laws E1 A9, E2

intersection near railroad crossing G3

intersection near fire station A5

excessive delay A6

disobedience of traffic signal A6 A9, D3, D8

CATEGORY E: IMPROVE 

DRIVER COMPLIANCE WITH 

TRAFFIC CONTROL DEVICES

lE1 – Provide public information and 

education

Where to use - Signalized intersections 

with a high frequency of crashes related to 

drivers either being unaware of (or refusing 

to obey) traffic laws and regulations that impact traffic safety (especially red-light 

running, speeding, and not yielding to pedestrians).

lE2 – Provide targeted conventional enforcement of traffic laws

Where to use -Signalized intersections with a high frequency of crashes related to 

drivers either being unaware of (or refusing to obey) traffic laws and regulations that 

impact traffic safety.

lE3 – Post reasonable, safe, and consistent speed limits on intersection 

approaches

Where to use - Signalized intersections with a high frequency of crashes attributed to 

drivers who intentionally disobey posted approach speed limits.

Keywords: Speed, speed management

BIKE PED

BIKE PED SIG

CATEGORY G: IMPROVE 

SAFETY THROUGH OTHER 

INFRASTRUCTURE TREATMENTS

lG1 – Improve drainage in 

intersection and on approaches

Where to use - Signalized intersections with 

a high frequency of crashes that are related 

to wet pavement from poor drainage. 

Such crashes involve vehicles that hydroplane and, hence, are not able to stop when 

required.

lG2 – Provide high friction surface treatment in intersection and on 

approaches

Where to use - Signalized intersection approaches where skidding is determined to be 

a problem, especially in wet conditions.

Keywords: pavement, friction, condition, skid resistance

lG3 – Coordinate closely spaced signals near at-grade railroad crossings

Where to use - Signalized intersections in close proximity to at-grade railroad crossings 

with a high frequency of crashes. This situation presents a significant potential for 

vehicle-train crashes, but vehicle-vehicle crashes could also occur if drivers try to speed 

through an intersection to avoid waiting in a queue near the railroad crossing.

lG4 – Relocate signal hardware out of clear zone 

Where to use - Signalized intersections where signal hardware is located within the 

clear zone or is a sight obstruction (particularly on high-speed approaches).

Keywords: fixed objects, clear zone

lG5 – Restrict or eliminate parking on intersection approaches 

Where to use - Signalized intersections with permitted parking on the approaches 

that may present a safety hazard either by blocking sight distance or due to parking 

maneuvers.

Keywords: on-street parking

SIG

PED

BIKE PED

CATEGORY F: IMPROVE 

ACCESS MANAGEMENT NEAR 

SIGNALIZED INTERSECTIONS

lF1 – Modify driveway access

Where to use - Signalized intersections 

with high crash frequencies related to 

driveways adjacent to the intersection. 

Generally, driveways within 250 feet of the 

intersection are the greatest concern.

Keywords: relocation, driveway, closure

lF2 – Corridor access management - implement median closures

Where to use - Approaches to signalized intersections with a high frequency of 

crashes involving drivers making turns across medians.

Keywords: open median, closed median

P

P

CATEGORY D: IMPROVE DRIVER 

AWARENESS OF INTERSECTIONS 

AND SIGNAL CONTROL

lD1 – Improve visibility of intersections 

on approach(es)

Where to use - Signalized intersections with 

a high frequency of crashes attributed to 

drivers being unaware of the presence of the 

intersection.

lD2 – Improve visibility of signals and signs at intersections 

Where to use -Signalized intersections with a high frequency of right-angle and 

rear-end crashes occurring because drivers are unable to see traffic signals and signs 

sufficiently in advance to safely negotiate the intersection being approached.

Keywords: signal visibility

lD3 – Install/add one signal head per lane 

Where to use - Signalized intersections with a high frequency of crashes caused by 

driver indecision in lane assignment.

Keywords: add signal, signal head

lD4 – Install larger 12” signal heads

Where to use - Signalized intersections with a crash history or observed conflicts 

involving lack of awareness of the intersection or traffic control and observed speeding 

on approaches to the intersection.

Keywords: signal lense, signal head

lD5 – Install signal backplate/retroreflective backplates 

Where to use - Signalized intersections with poor visibility of the intersection from 

approaches, a crash history or observed conflicts involving lack of awareness of 

the intersection or traffic control, and observed speeding on approaches to the 

intersection.

Keywords: retroreflective, backplate

lD6 – Install intersection warning devices 

Where to use - Signalized intersections with poor visibility of the intersection from 

approaches, conflicts involving lack of awareness of the intersection or traffic control, 

and observed speeding on approaches to the intersection. Intersection warning 

devices can include warning signs, beacons, and transverse rumble strips.

Keywords: advance warning sign, positive guidance

lD7 – Convert pole mounted to overhead signals

Where to use - Signalized intersections with poor visibility of the intersection from 

approaches, a crash history or observed conflicts involving lack of awareness of 

the intersection or traffic control, and observed speeding on approaches to the 

intersection.

Keywords: convert signal, pedestal mounted, mast arm

lD8 – Install supplemental pole-mounted signal on near-side approach

Where to use - Signalized intersections with poor visibility of the intersection from 

approaches, a crash history or observed conflicts involving lack of awareness of 

the intersection or traffic control, and observed speeding on approaches to the 

intersection.

Keywords: add signal, signal head

SIG

SIG

SIG

P

BIKE PED

SIG

FHWA Signalized Intersections: An Informational Guide (2nd Edition): 

http://safety.fhwa.dot.gov/intersection/signalized/13027/fhwasa13027.pdf

Unsignalized Intersection Improvement Guide (NCHRP 03-104)

BIKESAFE 2014- Bicycle Safety Guide and Countermeasure Selection 

System http://pedbikesafe.org/BIKESAFE/guide_background.cfm

PEDSAFE 2013- Pedestrian Safety Guide and Countermeasure Selection 

System http://pedbikesafe.org/PEDSAFE/guide_background.cfm

SIG

UNSIG

BIKE

PED

CATEGORY A: REDUCE 

FREQUENCY AND SEVERITY 

OF INTERSECTION CONFLICTS 

THROUGH TRAFFIC CONTROL 

AND OPERATIONAL 

IMPROVEMENTS

lA1 – Replace permissive left turns 

with protected left turns

Where to use - Signalized intersections with a high frequency of angle crashes 

involving left turning and opposing through vehicles. A properly timed protected leftturn phase can also help reduce rear-end and sideswipe crashes between left-turning 

vehicles and the through vehicles behind them.

Keywords: protected, permissive, signal phasing

lA2 – Optimize change and clearance intervals

Where to use - Signalized intersections with a high frequency of crashes related to 

change interval lengths that are possibly too short. These crashes include angle 

crashes between vehicles continuing through the intersection after one phase has 

ended and the vehicles entering the intersection on the following phase. Rear-end 

crashes may also be a symptom of short change intervals.

Keywords: change interval, signal phasing, signal timing

lA3 – Restrict or eliminate turning maneuvers

Where to use - Signalized intersections with a high frequency of crashes related to 

turning maneuvers. For right turn on red (RTOR), the target of this strategy is rightturning vehicles that are involved in rear-end or angle crashes with cross-street vehicles 

approaching from the left or vehicles turning left from the opposing approach, and 

crashes involving pedestrians.

Keywords: right turn on red

lA4 – Employ signal coordination

Where to use - Signalized intersections with a high frequency of crashes involving 

major street left-turning and minor street right-turning vehicles where adequate safe 

gaps in opposing traffic are not available. Major road rear-end crashes associated with 

speed changes can also be reduced by re-timing signals to promote platooning.

Keywords: signal coordination, signal timing, cycles

lA5 – Employ emergency vehicle preemption

Where to use - Signalized intersections where normal traffic operations impede 

emergency vehicles and where traffic conditions create a potential for conflicts 

between emergency and non-emergency vehicles.

lA6 – Remove unwarranted signal

Where to use - Signalized intersections where the traffic volumes and safety record do 

not warrant a traffic signal.

Keywords: unwarranted, remove signal

lA7 – Change green signal to flashing yellow arrow for permissive left turns

Where to use - Signalized intersections with high frequency of angle crashes involving 

left-turning and opposing through vehicles. The flashing yellow arrow (FYA) can be 

used in place of the simple circular green light and other signals to help convey the 

message that left-turning drivers need to yield to on-coming traffic. 

Keywords: FYA, flashing yellow arrow, phasing, left turn, protected, permissive

lA8 – Install/implement pedestrian signal improvements

Where to use - Signalized intersections with conflicts between vehicles and 

pedestrians crossing at the intersection, high volume of crossing pedestrians or 

bicyclists, vehicles not yielding to pedestrians in crosswalk, and high pedestrian 

delay due to few available gaps in traffic. Measures can include increasing 

pedestrian clearance intervals (or increasing the cycle length for pedestrian crossing), 

implementing leading pedestrian interval and installing pedestrian pushbuttons and 

pedestrian countdown signals.

Keywords: pedestrian, crossing, cycle length, signal phasing, pedestrian interval, countdown

lA9 – Install bicycle signal

Where to use - Signalized intersections with conflicts between vehicles and bicycles 

crossing at the intersection, high volume of bicyclists, vehicles not yielding to bicyclists.

SIG

SIG

PED SIG

PED

PED

BIKE

FHWA-SA-15-085
UNSIGNALIZED INTERSECTION SAFETY STRATEGIES

CATEGORY A: IMPROVE 

MANAGEMENT OF ACCESS

lA1 – Corridor access management - 

reduce driveway conflicts

Where to use - Unsignalized intersections 

with high crash frequencies related to 

driveways adjacent to the intersection. 

Generally, driveways within 250 feet of the 

intersection are the greatest concern.

Keywords: driveway closure, driveway relocation, access management, reduce driveways

lA2 – Corridor access management - modify driveway access 

Where to use - Driveways located near unsignalized intersections that experience high 

crash frequencies but that cannot practically be closed or relocated.

Keywords: access management, turn prohibitions, prohibit left-turns

lA3 – Corridor access management - reduce number of intersections

Where to use - Corridors with many intersections in close proximity and a high number 

of intersection related crashes. Reducing the number of intersections reduces the 

number of conflict points and can improve traffic flow along the corridor.

Keywords: intersection spacing, access management, change number of legs

lA4 – Corridor access management - implement median closures

Where to use - Unsignalized intersections that have observed conflicts with left-turning 

vehicles from the major or minor road, finding acceptable gaps from minor road, and 

where driveway access causes delay and/or collisions.

Keywords: closed median, convert open medians

P

P

P

P

CATEGORY E: IMPROVE 

DRIVER AWARENESS

lE1 – Improve visibility of 

intersections by providing enhanced 

signing and delineation

Where to use - Unsignalized intersections 

that are not clearly visible to approaching 

motorists, particularly approaching 

motorists on the major road. The strategy 

is particularly appropriate for intersections with patterns of rear-end, right-angle, or 

turning crashes related to lack of driver awareness of the presence of the intersection. 

Measures can include installing larger or supplementary regulatory and warning signs 

at intersections or providing dashed markings (extended left edge-lines) for major-road 

continuity across the median opening at divided highway intersection.

lE2 – Improve visibility of the intersection by providing lighting 

Where to use - Unsignalized, unlit intersections with substantial patterns of nighttime 

crashes. In particular, patterns of rear-end, right-angle, or turning crashes on the majorroad approaches to an unsignalized intersection may indicate that approaching drivers 

are unaware of the presence of the intersection.

Keywords: illumination, lighting

lE3 – Install splitter islands on the minor-road approach to an intersection

Where to use - Minor road approaches to unsignalized intersections where the 

presence of the intersection or the stop sign is not readily visible to approaching 

motorists. The strategy is particularly appropriate for intersections where the speeds on 

the minor road are high.

Keywords: channelizing separator islands, splitter island

lE4 – Provide a stop line on minor-road approaches 

Where to use - Approaches to unsignalized intersections having traffic control devices 

that are not currently being recognized by some approaching motorists. Locations 

should be identified by patterns of crashes related to lack of driver recognition of the 

traffic control device (e.g., right-angle crashes related to stop sign violations).

Keywords: centerline, stop bar, stop sign

lE5 – Install transverse rumble strips on intersection approaches

Where to use - Approaches to unsignalized intersections with traffic control devices 

that are not currently being recognized by some approaching motorists. Locations 

should be identified by patterns of crashes related to lack of driver recognition of the 

traffic control device (e.g., right-angle crashes related to stop sign violations). Rumble 

strips should be considered after an adequate trial of less intrusive treatments.

Keywords: traverse rumble strips, stop controlled approach

lE6 – Provide supplementary stop signs mounted over the roadway

Where to use - Unsignalized intersections with patterns of right-angle crashes related 

to lack of driver awareness of the presence of the intersection. In particular, it might 

be appropriate to use this strategy at the first stop-controlled approach (possibly of 

a series) located on a long stretch of highway without any required stops, or at an 

intersection located after a sharp horizontal curve.

lE7 – Provide pavement markings with supplementary messages, 

such as STOP AHEAD

Where to use - Unsignalized intersections with patterns of rear-end, right-angle, or 

turning crashes related to lack of driver awareness of the presence of the intersection.

Keywords: STOP AHEAD, pavement marking

lE8 – Provide improved maintenance and retroreflectivity of stop signs 

Where to use - All stop-controlled intersections.

Keywords: retroreflectivity, stop sign

lE9 – Install flashing beacons at stop-controlled intersections

Where to use - Unsignalized intersections with patterns of right-angle crashes related 

to lack of driver awareness of the intersection on an uncontrolled approach and lack of 

driver awareness of the stop sign on a stop-controlled approach.

Keywords: flashing beacon, stop controlled

lE10 – Add a warning beacon to an existing regulatory or warning sign 

(Provide flashing beacons at stop controlled intersections)

Where to use - Unsignalized intersections with a crash history or observed vehicle 

conflicts caused by non-compliance with a traffic control device or lack of awareness 

of intersection traffic control and where the existing sign is not conspicuous in its 

surroundings.

lE11 – Provide intersection warning signs

Where to use - Unsignalized intersections with poor visibility of the intersection 

from approaches, a crash history or observed conflicts involving lack of awareness 

of the intersection or traffic control, and observed speeding on approaches to the 

intersection.

lE12 – Provide Advance Traffic Control Warning signs 

(Install advance warning signs (positive guidance)) 

Where to use - Unsignalized intersections with poor visibility of the intersection traffic 

control from one or more approaches.

lE13 – Install post-mounted reflective delineators at the intersection

Where to use - Unsignalized intersections with a history of nighttime crashes, remote 

stretches in which intersections may not be conspicuous to drivers along the major 

road, and poor nighttime visibility of the intersection.

lE14 – Install reflective strips on sign posts

 Where to use - Unsignalized intersections with observed poor conspicuity of existing 

signs, particularly at night, crash history or observed conflicts due to lack of awareness 

of the intersection or intersection traffic control, especially at night, and observations 

of non-compliance with traffic control.

Keywords: enhance regulatory

lE15 – Provide a yield line on yield-controlled approaches

Where to use -Unsignalized intersections with a crash history or observed conflicts 

related to failure to yield to the right-of-way.

lE16 – Replace standard stop sign with flashing LED enhanced stop sign

Where to use - Unsignalized intersections with a crash history or observed vehicle 

conflicts caused by non-compliance with traffic control device or lack of awareness 

of intersection traffic control, an existing sign that is not conspicuous in its current 

surroundings, and poor sign visibility during low-light conditions.

Keywords: enhance warning

lE17 – Install red or orange flags with a regulatory or warning sign

Where to use - Unsignalized intersections with conflicts caused by non-compliance 

with traffic control device or lack of awareness of intersection traffic control, an existing 

sign that is not conspicuous in its surroundings, and a recent change in traffic control 

or traffic regulation.

lE18 – Enhance pedestrian signing

Where to use - Use such signs as a Pedestrian Warning sign (W11-2), Turning Vehicles 

Yield to Peds sign (R10-15), Pedestrian Crossing Sign (R1-5, R1-9, R9-2, R9-3), and 

In-Street Pedestrian Crossing Sign (R1-6) at unsignalized intersections with conflicts 

between vehicles and pedestrians crossing the roadway, vehicles that are not yielding 

to pedestrians in existing crosswalk or unmarked crosswalk.

lE19 – Replace transverse crosswalk markings with high visibility markings

Where to use - Unsignalized intersections with conflicts between vehicles and 

pedestrians crossing the roadway, vehicles that are not yielding to pedestrians in 

existing crosswalk or unmarked crosswalk.

lE20 – Provide advance yield line

Where to use - Unsignalized intersections with conflicts between vehicles and 

pedestrians crossing the roadway, vehicles that are not yielding to pedestrians in 

existing crosswalk.

PED

PED BIKE

PED BIKE

PED BIKE

PED

PED

CATEGORY I: GUIDE 

MOTORISTS MORE 

EFFECTIVELY

lI1 – Provide turn path markings 

Where to use - Complex unsignalized 

intersections with a high frequency 

of crashes related to turning vehicle 

positioning (e.g., sideswipe crashes).

Keywords: channelization

lI2 – Provide a double yellow centerline on the median opening of a divided 

highway at intersections

Where to use - Unsignalized intersections on divided highways that are experiencing a 

high degree of crashes caused by side-by-side queuing and angle stopping within the 

median area.

lI3 – Provide a double yellow centerline on the minor road approaches 

Where to use - Unsignalized intersections with conflicts between stopped vehicles and 

turning or oncoming vehicles and poor vehicle positioning.

Keywords: centerline, stop bar, stop sign

lI4 – Provide dotted edge-line extensions

Where to use - Unsignalized intersections with vehicles on the minor approaches not 

positioning themselves appropriately before entering the major road and vehicles in 

the median of a divided roadway that are encroaching upon the major road through 

lane.

UNSIG

UNSIG

CATEGORY B: REDUCE 

CONFLICTS THROUGH GEOMETRIC 

DESIGN IMPROVEMENTS

lB1 – Provide left-turn lanes at 

intersections Where to use - Unsignalized 

intersections with a high frequency of crashes 

resulting from the conflict between (1) vehicles 

turning left and following vehicles and (2) vehicles 

turning left and opposing through vehicles.

Keywords: provide left turn lane

lB2 – Provide provide zero or positive 

offset left-turn lanes at intersections 

Where to use - Unsignalized intersections with a high frequency of crashes between 

vehicles turning left and opposing through vehicles, as well as rear-end crashes 

between through vehicles on the opposing approach. Also at intersections on divided 

highways with medians wide enough to provide the appropriate offset but can be 

implemented on approaches without medians if sufficient width exists.

Keywords: positive offset turn lane

lB3 – Provide left or right-turn bypass lanes on shoulders at T-intersections 

Where to use - At three-legged unsignalized intersections on two-lane highways with 

moderate through and turning volumes, especially intersections that have a pattern of 

rear-end collisions involving vehicles waiting to turn left from the highway.

Keywords: by-pass lane

lB4 – Provide left-turn acceleration lanes in median at divided highway high 

speed intersections

Where to use - Unsignalized intersections with conflicts due to speed differential 

between entering vehicles and through vehicles, high left-turn volumes onto highspeed major roads, and significant delay for left-turning vehicles waiting for a suitable 

gap on the major road.

Keywords: provide right turn lane 

lB5 – Provide right-turn lanes at intersections 

Where to use - Unsignalized intersections with a high frequency of rear-end crashes 

resulting from conflicts between (1) vehicles turning right and following vehicles and 

(2) vehicles turning right and through vehicles coming from the left on the cross street.

Keywords: provide right turn lane

lB6 – Provide offset right-turn lanes at intersections 

Where to use - Unsignalized intersections with a high frequency of crashes between 

vehicles on the minor road that are turning left, turning right, or proceeding straight 

through, and vehicles on the major road.

Keywords: offset right turn lane 

lB7 – Provide full-width paved shoulders in intersection areas 

Where to use - Unsignalized intersections on divided highways with no shoulder or 

shoulder widths less than 8 feet that experience a high proportion of run-off-road 

crashes as a result of avoidance maneuvers or a high proportion of rear-end crashes 

that could have been avoided had a full-width paved shoulder been provided.

Keywords: shoulder width, 12 feet shoulder, pave full-width shoulder 

lB8 – Modify allowed turning maneuvers through geometric improvements 

Where to use - Unsignalized intersections with patterns of crashes related to particular 

turning maneuvers where it is impractical to reduce that pattern of crashes by 

improving sight distance or providing a left-turn or shoulder bypass lane. Also, at 

locations where it is possible to restrict or eliminate turning maneuvers by providing 

channelization or by closing the median opening (Replace direct left-turn with rightturn/U-turn).

Keywords: replace direct left with right turn / u turn 

lB9 – Convert four-legged intersections to offset T-intersections

Where to use - Unsignalized four-legged intersections with very low through volumes 

on the cross street.

Keywords: convert four-leg to two three-leg 

lB10 – Convert offset T-intersections to four-legged intersections

Where to use - Unsignalized offset T-intersections where through volumes on the cross 

street are very high.

lB11– Realign intersection approaches to reduce or eliminate intersection skew

Where to use - Unsignalized intersections with a high frequency of crashes resulting 

from insufficient intersection sight distance and awkward sight lines at a skewed 

intersection.

Keywords: change skew angle 

lB12 – Reduce or extend curb radius

Where to use - Unsignalized intersections with observed vehicles making right-turn 

movements at high speeds, high pedestrian traffic, poor visibility of on-coming traffic 

for pedestrians waiting to cross the road, and a crash history or observed conflicts 

between bicyclists and/or pedestrians and right-turning vehicles.

Keywords: widen sidewalk 

lB13 – Install medians and pedestrian crossing islands

Where to use - Unsignalized intersections with crossings that span multiple lanes and 

observed difficulty of pedestrians finding safe gaps in traffic to cross. 

Keywords: raised median 

lB14 – Install roundabout or mini-roundabout

Where to use - Unsignalized intersections with a crash history or observed conflicts 

related to speeding through the intersection. 

Keywords: roundabout 

P

P

P

PED

PED BIKE

PED P

PED BIKE P

CATEGORY G: IMPROVE 

COMPLIANCE WITH TRAFFIC 

CONTROL DEVICES AND 

TRAFFIC LAWS

lG1 – Provide targeted enforcement 

to reduce stop sign violations

Where to use - Unsignalized intersections 

where stop sign violations and patterns 

of crashes related to stop sign violations have been observed. Crash types potentially 

related to stop sign violations include right-angle and turning collisions.

lG2 – Provide targeted public information and education on safety 

problems at specific intersections

Where to use - Jurisdictions that have experienced a large number of safety problems 

at unsignalized intersections.

UNSIGNALIZED COST

SAFETY CONCERN lLow lModerate lHigh

High frequency of right-angle crashes 

attributed to:

nearby driveways A2, C1, C3 A1, B6, B8

traffic from minor street C1, C3, D2, E4 B6, B8, D1 A3, F2

skewed intersection B11, C2, F2

poor sight distance C1, C3, H3 D1 C2, F2

drivers misjudging gaps H3, H6 A4, D1 F2, F5

not enough gaps for drivers D2, F1 A4 B9, F2, F5

driver unaware of intersection E1, E4-E14, E16, E17 E3

nighttime conditions E8 E2

failure to yield at stop or yield sign E1, E4, E20 G1 F2

possible signal location F2

heavy but balanced traffic flow F2

speed differentials of vehicles H3, H6 A4, H1, H2 F2

High frequency of rear-end crashes 

attributed to:

left turning vehicles hit from behind B3 B1, B2, B3 F2

left opposing vehicles hit from behind B2 F2

trucks and RVs entering divided highway B4

speed differential of entering vehicles B4 F2

right turning vehicles hit from behind B5, B6 B11, F2

approaching vehicles hit from behind B7

no left turn lane and high opposing traffic B8

driver unaware of intersection E1, E5-E14, E16, E17 E3

nighttime conditions E2

speed differentials of vehicles H3, H4, H6 H1, H2, H5 F2

High frequency of left-turn crashes 

attributed to:

left turn vehicles hit by opposing traffic B1 B10, B14, C2, F2, F5

trucks and/or RVs entering divided highway B4

no left turn lane and high opposing traffic B8

nighttime conditions E10 E2

heavy but balanced traffic flow F2

Poor sight distance C2

High frequency of sideswipe crashes 

attributed to:

speed differential of entering vehicles H6 F2

vehicles within intersection I1,I2 B12

vehicles approaching intersection I3

High frequency of run off road 

crashes:

approaching intersection I4 B7

High frequency of pedestrian/bicycle crashes:

E18-E20 B12-B13, F3-F4, H2

Address overall safety issues:

violation of traffic laws G2 G1

lH1 – Provide targeted speed 

enforcement

Where to use - Unsignalized intersections 

where speed violations and patterns of 

crashes related to speed violations are 

observed. Crash types potentially related to 

speed violations include right-angle, rear-end, and turning crashes.

lH2 – Provide traffic calming on intersection approaches through a 

combination of geometric and traffic control devices

Where to use - Specific approaches to unsignalized intersections that are experiencing 

crash types potentially related to speed violations, specifically right-angle, rear-end, 

and turning collisions.

lH3 – Post reasonable, safe, and consistent speed limits on intersection 

approaches 

Where to use - Unsignalized intersections experiencing a high frequency of speed 

related violations or crashes.

Keywords: lower posted speed, speed limit

lH4 – Provide speed reduction pavement markings

Where to use - Unsignalized intersections with a citation history or observations of 

speeding on the approach to the intersection and conflicts due to lack of awareness of 

the intersection.

lH5 – Provide a dynamic speed feedback sign 

Where to use - Unsignalized intersections with a citation history or observations of 

speeding on approach to intersection, change in speed limit or land use (e.g., change 

from rural to urban), and changeable speed limit by time and day of the week (e.g., 

during school hours).

Keywords: changeable speed warning signs

lH6 – Provide smooth lane narrowing 

Where to use - high-speed, uncontrolled approaches of two-lane two-way stop 

controlled intersections with low traffic volumes to reduce speeds when approaching 

such intersections. Lane narrowing can be accomplished through pavement markings 

or a combination of pavement markings and edge line/shoulder/median rumble strips.

Keywords: lane narrowing, rumble strips, painted median

PED BIKE

PED

UNSIG

UNSIG

UNSIG

CATEGORY H: REDUCE 

OPERATING SPEEDS

CATEGORY C: IMPROVE 

SIGHT DISTANCE

lC1 – Clear sight triangles on stopor yield-controlled approaches to 

intersections or in the medians of 

divided highways near intersections

Where to use - Unsignalized intersections 

or medians with restricted sight distance 

and patterns of crashes related to lack of sight distance, where sight distance can be 

improved by clearing roadside or median obstructions without major construction.

Keywords: increase triangle sight distance

lC2 – Change horizontal and/or vertical alignment of approaches to provide 

more sight distance

Where to use - Unsignalized intersections with restricted sight distance due to 

horizontal and/or vertical geometry and with patterns of crashes related to that lack of 

sight distance that cannot be ameliorated by less expensive methods.

lC3 – Eliminate parking that restricts sight distance 

Where to use - Unsignalized intersections with restricted sight distance due to parking.

Keywords: prohibit on-street parking

BIKE

BIKE

BIKE

CATEGORY D: IMPROVE 

AVAILABILITY OF GAPS 

AND ASSIST DRIVERS IN 

JUDGING GAPS

lD1 – Install an intersection conflict 

warning system (ICWS) 

Where to use - Unsignalized intersections 

with a crash history involving vehicles 

entering or crossing the major road, difficulty among drivers in determining 

appropriate gaps in traffic, and awareness of the intersection is lacking.

Keywords: install dynamic advance intersection warning system

lD2 – Re-time adjacent signals to create gaps at stop-controlled 

intersections Where to use - Unsignalized intersections (between signalized 

intersections) with a high frequency of right-angle or turning related crashes due to a 

lack of sufficient gaps in through traffic on the major road.

UNSIG

CATEGORY F: CHOOSE 

APPROPRIATE INTERSECTION 

TRAFFIC CONTROL

lF1 – Provide all-way stop-control at 

appropriate intersections 

Where to use - Unsignalized intersections 

with patterns of right-angle and turning 

crashes and moderate and relatively 

balanced volumes on the intersection approaches.

Keywords: stop control, all-way stop

lF2 – Provide roundabouts at appropriate locations

Where to use - Unsignalized intersections that are experiencing right-angle, rearend, and turning crashes. Roundabouts are appropriate at most intersections, and at 

intersections with large traffic delays roundabouts are oftentimes a superior alternative 

to all-way stop or signalization. Roundabouts can also be very effective at intersections 

with complex geometry (e.g., more than four approach roads) and intersections with 

frequent left-turn movements.

Keywords: roundabout, unsignalized

lF3 – Provide pedestrian hybrid beacon

Where to use - Unsignalized intersections with conflicts between vehicles and nonmotorists crossing at the intersection, high volume of crossing pedestrians or bicyclists, 

vehicles not yielding to pedestrians in crosswalk, and high pedestrian delay due to few 

available gaps in traffic.

Keywords: high intensity activated crosswalk, pedestrian activated beacon

lF4 – Provide rectangular rapid flashing beacon

Where to use - Unsignalized intersections with conflicts between vehicles and nonmotorists crossing at the intersection, high volume of crossing pedestrians or bicyclists, 

vehicles not yielding to pedestrians in crosswalk, and high pedestrian delay due to few 

available gaps in traffic.

lF5 – Convert a unsignalized intersection to an unsignalized restricted crossing 

U-turn (also known as a J-turn)

Where to use - Unsignalized intersections with conflicts involving left-turning vehicles 

or vehicles attempting to continue on the minor road by crossing the major road, 

insufficient gaps in major road traffic for left-turn or through movements from minor 

road, and conflicts involving vehicles in the median.

Keywords: super-street, j-turn, rcut

PED BIKE P

PED BIKE P

PED BIKE

P

Key to the Brochure

Costs:

Costs will also vary considerably and are affected by local conditions. Costs are ranked 

as: low, moderate, moderate to high, and high. The scale is meant to reflect costs 

relative to the other strategies described in the category (signalized or unsignalized).

lLow Cost Measure lModerate Cost Measure lHigh Cost Measure

 FHWA Proven Safety Countermeasure: 

More information about FHWA Proven Safety Countermeasures can be found at: 

http://safety.fhwa.dot.gov/provencountermeasures/

 FHWA Everyday Counts: 

Every Day Counts (EDC) is an effort led by FHWA in coorperation with American 

Association of State and Highway and Transportation Officials (AASHTO) to identify and 

rapidly deploy proven but underutilized innovations to shorten the project delivery 

process, enhance roadway safety, reduce congestion and improve environmental 

sustainability. See http://www.fhwa.dot.gov/everydaycounts/ for additional 

information.

Keywords:

Keywords have been provided for those countermeasures with a crash modification 

factor in the CMF Clearinghouse (http://www.cmfclearinghouse.org/). Some 

countermeasures may be found using a variety of search terms and the keywords 

provided are examples of those terms. For those countermeasures without keywords 

listed, their effectiveness may not have been studied or submitted to the CMF 

clearinghouse. 

P

E

FHWA Signalized Intersections: An Informational Guide (2nd Edition): 

http://safety.fhwa.dot.gov/intersection/signalized/13027/fhwasa13027.pdf

Unsignalized Intersection Improvement Guide (NCHRP 03-104)

BIKESAFE 2014- Bicycle Safety Guide and Countermeasure Selection 

System http://pedbikesafe.org/BIKESAFE/guide_background.cfm

PEDSAFE 2013- Pedestrian Safety Guide and Countermeasure Selection 

System http://pedbikesafe.org/PEDSAFE/guide_background.cfm

SIG

UNSIG

BIKE

PED