A companion document to the report,

Making Intersections Safer:A Toolbox of Engineering Countermeasures to Reduce Red-Light Running

Field Guide for 

Inspecting Signalized 

Intersections to 

Reduce Red-Light 

Running 

U.S. Department of TransportationFederal Highway Administration
Introduction

The Federal Highway Administration (FHWA) recognizesred-light running as a national safety problem, resulting in asmany as 176,000 injuries and 1,000 fatalities annually, and aneconomic loss estimated at $14 billion per year. The solution to the problem involves education, enforcement andengineering measures. To publicize the engineering measuresthat can be taken, FHWA and the Institute of TransportationEngineers (ITE) prepared a report to provide informationthat could be used to proactively ensure that intersectionscan be engineered to discourage red-light running. The finalproduct, Making Intersections Safer:A Toolbox of EngineeringCountermeasures to Reduce Red-Light Running (1), addressesdesign and operational features that may need to be upgraded or modified to discourage red-light running. The reportcharacterizes the red-light running safety problem, identifiesand provides guidance on the application of numerous engineering measures that can be taken to reduce red light running, and provides a separate chapter describing a processfor addressing the safety problem at a specific location.To supplement this report and provide more details on howto conduct a site investigation, this field guide was prepared.The field guide suggests a procedure for conducting an investigation of a specific intersection that has been identified as ared-light running problem site. Presumably this identificationhas resulted from a review of red-light running violation andcrash data. Having done so, the next step should be aninvestigation of the site to identify possible engineering deficiencies that could contribute to violations and crashes, andto form initial opinions as to the possible countermeasures.Final selection of appropriate countermeasures should bemade based on further engineering analyses.The field inspection guide is prepared in connection with theIntersection Field Inspection Form found at the end of the guide.

3

ment is disseminated under the sponsorship of

partment of Transportation in the interest of

 exchange. The U.S. Government assumes no

its contents or the use thereof.

 does not constitute a standard, specification,

on. The U.S. Government does not endorse

r manufacturers. Any trade or manufacturer’s

appear herein are only because they 

red essential to the object of this document.

y be obtained from the FHWA Report Center

o report.center@fhwa.dot.gov by fax to 

21, or by phone to 301-577-0818, or may 

aded from the FHWA website at:

y.fhwa.dot.gov/intersections/redl_reports.htm.

dgements:

prepared by:

cGee, Ph.D., P.E.

ccles, P.E.

HB company

e Boulevard, Suite 400

inia 22182

71

ute of Transportation Engineers. All rights reserved.

No. IR-121; FHWA-SA-05-008

452-04-8

 United States of America
In view of this general goal, items to be considered in the

review include: Visibility/conspicuity of signal indication; Signal timing and phasing; Traffic operations; and Geometric design and pavement condition.Materials and Personnel NeededThe materials required for conducting the field site reviewinclude the following: Field guide; Field Inspection Form with clipboard; Measuring device, preferably a measuring wheel; Camera, preferably digital—a video camera is optional; Stopwatch—to time the traffic signal intervals; and  Slope meter—to measure the grade on the approaches.The inspection can be made by one person who has trainingand/or experience in traffic engineering principles. A secondperson is desirable to assist in the required measurementsand to “get a second opinion” about deficiencies or possiblecountermeasures.As with all field work,the inspectors should follow the agency’s policiesand procedures regarding personnel safety and traffic control.

5

jective

 of the field site review is to identify any engi

gn or operational deficiencies that may con

d-light running and the resulting crashes and to

pinions as to possible countermeasures. From

ng perspective, red-light running may be reduced

any one of these actions is taken:

at the traffic signals, and in particular, the red dis

visible from a sufficient distance and capture the

tention;

he likelihood of drivers stopping for the rede seen;

ntentional violations; and 

the need to stop.

unt that the driver can see the traffic signal dis

ugh in advance of the intersection so that

top safely upon viewing the yellow or red dis

pon viewing the yellow, and certainly the red

sure that the signal operations and conditions

e the driver to intentionally or unintentionally

. We must also ensure that a driver who tries

er vehicle can successfully do so before entering

ion.

that some drivers will intentionally violate the

certain times and situations, those conditions

ge this behavior must be minimized. Finally,

ould examine whether or not the traffic signal is

propriate choice of control for the intersection.

n should be given to the possible replacement

with another form of traffic control or design

es the signal (e.g. a roundabout) and, therefore,

running problem.

Field Site Review
n Field Inspection Form has been prepared to assist

tion and is included at the end of the field guide.

also included full-size (8 1/2 x 11 inch) as a PDF

rg/library/redlight/FieldInspectionForm.pdf and at

hwa.dot.gov/intersections/redl_reports.htm.

wnloaded from these sites and multiple copies

Alterations to the form may be necessary to

eds of your organization. How to use the form

ned in the remainder of this guide.

formation

ries are to record the name of the intersection

ific approach. An inspection form is needed

proach that is to be inspected. It is recom

 an inspection be conducted for all approaches

r more legs or approaches has not been identi

blem—upon inspection one or more deficiencies

ected on the “non-problem” approaches.

are as follows:

tion Identification: Enter the names and/or

mbers or any other intersection identifier used

gency.

h Name: Enter the name and/or route 

f the approach.

n Heading: Enter the cardinal direction (for

northbound) for the approach being investigated.

Part 1. Check Signal Visibility The first item to check is the signal visibility available to drivers as they approach the signal. Here, you need to confirmwhether or not there are unobstructed sight lines to the signal heads from a sufficient distance upstream.The entries tobe made are as follows:Type of Signal Mounting: Traffic signal heads can beplaced on 1) span wire, 2) mast arm, 3) a pole, or 4) a structure. For any given approach, there may be any combination of the above. Also, signal heads can be placed nearside (just at or before the physical intersection), within theintersection boundaries, or far-side (just beyond the crossroad). On the field sheet, indicate the type of signal mounting. If more than one mounting is used, then indicate this.You might want to take photographs of the signal displays foreach approach, both from a distance and then close to theintersection.

7

section Field Inspection Form

Mast Arm Mounting Span Wire Mounting Pole Mounting
Is anything blocking the view of the signals?: Even

though the minimum sight distance is met, continuous view toall or a portion of the signal face may be blocked by eitherutility lines, tree branches, or other objects. Drive towardsthe signals from a sufficient distance upstream in eachapproach lane and take note if this situation exists. Note thenature of the blockage and take a photograph of it (considersummertime if the inspection is being made during the nonfoliage seasons). If the opportunity presents itself, drivebehind any box-type trucks to see if they block the view.Can signal faces on other approaches be seen?:Intersections with more than four approach legs and thosewith approaches at non-90 degree angles frequently experience a situation where the signal displays for other approaches can be seen from the approach being investigated. If notproperly shielded with visors, this can cause driver confusionand some drivers may misinterpret the signal display for theappropriate approach. Indicate if this situation exists and ifyes, mark whether visors, shields, or programmable lenses arebeing used. Check each lane on the approach.

9

nce to the Signal (Section 4.D.15): The

niform Traffic Control Devices (MUTCD), (2) stipu

ignal faces cannot be seen within the minimum

own in Table 1, then a sign shall be installed to

ching traffic of the traffic signal. If any approach

 and/or grade that restricts visibility/sight dis

re the distance from the nearest signal head for

movement to the point on the approach where

first in view. Compare the distance to the val

 for the appropriate speed. If the 85th per

 is not known, choose a speed that is at least

er than the posted speed limit. Measuring the

e is not necessary if the signal is clearly visible

derable distance upstream.

dvance Warning Sign?: If the sight distance is

uired by the values in Table 1, indicate by circling

se circle no.

gnal Warning Sign Present?: Indicate if there

e signal warning sign. Take a photograph of the

ve a camera.

202530354045505560

175215270325390460540625715

Table 1: Minimum Sight Distance

85th-Percentile

Speed (mph)

Minimum Sight

Distance (feet)

Signal Blockage

Conflicting Signal

Displays
Are Signal Indications Confusing?: The next check is to

determine if the signal indications may be confusing.Sometimes signal head placement can be confusing or mistakenly identified to a driver approaching the intersection.For example, signals for left-turn traffic can be confused withthose for through traffic, especially if there is a NO LEFTTURN (R3-2) sign. Also, if there is another signalized intersection a short distance downstream, and depending uponthe approach grades, the signal for the second intersectioncan be confused for being the control for the first intersection. This could be particularly troublesome if the first signaldisplays red while the second signal displays green. Makenote if any confusing condition exists.Are backplates present? Are backplates necessary?:Answer yes or no.Glare from the sun can make it difficult to see one or moresignals as the driver approaches the intersection. Backplatesenhance visibility and conspicuity of the signal indication bymaking it stand out. When you are in the field noticewhether or not there are backplates on the signal.Even if there are backplates, if the approach is on direct eastor west bearing, then an inspection should be made duringthe critical period when the rising or setting of the sun willhave the worst effect on signal visibility. If the inspectionindicates that the sun glare is a problem and backplates areneeded, circle yes to that question. Also, indicate whetheror not other glare-reducing steps are needed. Re-positioningone or more of the signals may be necessary in this case.Signal Lens Type: Note if the red signal lenses have eitherincandescent bulbs or LEDs. Signals with LED lenses aretypically brighter than incandescent bulbs.Signal Lens Size Adequate?: The next entries determineif the size of the red-signal lens as determined by its diameter is adequate.

11

Check Signal Conspicuity

l clutter detract from signal detection?:

nals may be visible from the required distances,

 be conspicuous to the driver. In terms of traffic

es, such as a traffic signal, conspicuity means the

 specific device to be seen among other highway

way features that compete for motorists’ attention.

ny roads and streets that have dense commercial

with many signs and other forms of advertising that

utter and make it more difficult for the motorist,

 who is unfamiliar with the road, to detect and

c signals. Where this occurs it may be necessary to

signal display with additional signals and/or a double

tion.

 possibility, it is recommended that the investigator

 the intersection and note on each approach

ot there is visual clutter. In doing so, the inspector

 imagine how a driver unfamiliar with the area

he scene. The inspection can be done during the

if there is reason to believe that nighttime would

re, a night inspection should be made as well. If it

at the visual clutter could detract from clearly see

circle yes.

Confusing Signal Displays
 Number of signals heads for major movement:

Note the total number of signal heads for the majormovement.

 Number of through lanes: Note the number of lanes

for the major movement.

 Is existing number adequate?: If there are less signal

heads for the through movement than the number ofthrough lanes, circle N in the last column.

Placement of Signal Heads: Note the placement of thesignal heads in relation to the marked lanes. If the signalheads are not centered over the marked lanes, circle N.

Part 3. Check Signal ControlParametersAn inappropriately short or long yellow-change interval andthe lack of an all-red clearance interval are two features thatcan contribute to red-light running and the resulting crashes.The yellow-change interval is simply the first interval following the green interval during which the yellow signal indication is displayed. The all-red clearance interval is an optionalinterval that follows a yellow-change interval and precedesthe next conflicting green interval. It is frequently referredto as the all-red interval, because all approaches have a redsignal display during this interval. The use of an all-red interval will not likely reduce red-light running violations, but itwill help to avoid crashes if red-light running occurs in thefirst few seconds of the red indication. The two intervals areusually considered together as the change period and can becalculated using the following formula found in the mostrecent edition of ITE’s Traffic Engineering Handbook (3):

13

al Lens Size: Note the size of the red signal

y are usually either 8 or 12 inches in diameter

g is usually not needed as the two sizes are dis

e to a trained signal technician). If all red signal

 12 inches, then they can be considered ade

here are any 8-inch signal lenses, then complete

wo entries.

 from stop line to signal: Enter in feet.

e signal present?: Enter yes or no.

ng Size Adequate?: If any red signal lens is 8

hen circle no if any of the following conditions

affic control and lane-use control signal heads

iew simultaneously;

earest signal face is between 120 and 150 ft.

 the stop line, unless a supplemental near-side

ace is provided;

gnal faces are more than 150 ft. from the stop line;

ght distance to the signals is less than required

e 1;

gnal is using an arrow;

th-percentile approach speed exceeds 40 mph;

ffic signal is unexpected;

ost-mounted signal heads are used; or

own that there is significant percentage of 

drivers.

l conditions that would indicate the need for

al lenses.

 Signal Heads Adequate?: The MUTCD

 there be at least two signal heads for the major

sually the thru movement, but may be for a turn

t). It is desirable to have one for each lane. To

 adequacy of signal heads, enter the following:
e period of yellow plus all-red

of approaching vehicle, expressed in miles per hour.

of intersection in ft.

on the intersection approach, in percent 

d by 100 (downhill is negative)

 above has been altered to include the assumed

and L, and a factor for converting miles per hour

 second.1 If your agency uses different values,

 need to modify the equation accordingly.

o terms of the equation are typically used for the

e interval and the last term is for the all-red

evaluate these features, determine the following:

f the approach is not level or reasonably so,

grade, which can be determined using a slope

ter the grade as a decimal, for example, a 5 per

ngrade is entered as -.05.

h Speed: Enter the approach speed in miles

(mph). If available, the 85th percentile speed

 used. If not, then speeds up to 10 mph higher

peed limit can be used.

reet Width: At a point closest to the intersec

ure the distance between the curbs, if any, or if

edge of the outside travel lanes of the crossroad.

distance in feet.

____________________________________________________________

rmula includes the following parameters:

reaction time of the motorist

 deceleration rate of the vehicle

hicle

ation can be found in the Traffic Engineering Handbook.

: Institute of Transportation Engineers, 1999.

Then, enter the following for the phase that serves thethrough movement on this subject approach: Yellow interval in seconds, and All-red interval in seconds.

These two times should be available from the controllerunit; if not, then it will be necessary to determine thesetimes in the field using a stopwatch.

Next, enter the following: Calculated Yellow: Calculate the yellow interval, which

is the first two parts of the equation and enter the calculated yellow-change interval on the form.

 Yellow-Change Interval Adequate?: Compare the calculated yellow-change interval to the actual yellow interval and note if it is adequate.

 Calculated All-Red: Using the last part of the equation

with values for cross street width (W) and approach speed(V), calculate the all-red interval and enter it on the form.

 Red-Change Interval Adequate?: Compare the calculated red-change interval to the actual interval and note if

it is adequate.

Part 4. Check Other Factors Horizontal Location of Signal Faces: With respect tored-light running, traffic signals not properly located at theintersection (see Part 2 “Placement of Signal Heads”) may

induce red-light running. Referring to Figure 1, if the signal isplaced too close to the stop line, the driver already stopped atthe line, may not be able to see the signal and may enter theintersection prematurely. Also, if the signal is placed furtheraway from the stop line than prescribed in Figure 1, then themotorist may not associate the signal with the stop line andinadvertently enter the intersection on red. On the form,enter the distance from the stop line to the first far-side signalfor the through movement.

15

CP = 1.0 + + __________ _____

1.47*V W

+20 

 (20 + 64.4g) 1.47*V
Reconsider Signal Installation: It is possible that traffic

signal control is no longer warranted and could be replacedwith a lower order control. A more detailed study is requiredto determine if the traffic signal should be removed. However,if it is observed during the inspection that the traffic volumelevels on both the major and minor street are light (even during the peak traffic periods), then this should be noted.Part 5. Identify PromisingCountermeasuresHaving completed the inspection and observed one or moredeficiencies, then potential countermeasures to address thedeficiency should be considered. On the form check off ifany of the deficiency types are identified and countermeasures that you feel may be appropriate. The potential countermeasures for each category of deficiency are listed below.Visibility Deficiency1) Install additional signals on the near side of the intersection2) Change signal mounting (to center over each marked lane)3) Remove/relocate sight obstructing object4) Install shields and visors5) Install programmable lenses6) Install SIGNAL AHEAD sign7) Install advance warning flashers

17

Condition: If the pavement surface along the

ar the stop line appears to be slippery because

polished condition or is severely rutted,

ay be reluctant to decelerate to a stop when the

rs and may subsequently run a red light.

 condition of the pavement along the approach

these conditions and circle the most applicable

 the form.

gure 1: Horizontal Location of Signal Faces

Source: MUTCD 2003
19

Intersection Field Inspection Form

LOCATION INFORMATION

Intersection Identification:

_________________________

with__________________________________________Approach Name: ________________________________ Direction Heading:_______________________________

PART 1. CHECK SIGNAL VISIBILITY

Type of Signal Mounting: Span Wire Mast Arm 

Pole Structure 

Sight Distance to the Signal: _______feet Requires Advance Warning Sign? Y N Advance Signal Warning Sign Present: Y N Is anything blocking the view of the signals? Y N 

If yes, describe_______________________________

__________________________________________

Can signal faces on other approaches be seen? Y N 

If yes, do these signals have visors,shields, or programmable lenses? Y N 

To download a one-page form, visit:

www.ite.org/library/redlight/FieldInspectionForm.pdf

http://safety.fhwa.dot.gov/intersections/redl_reports.htm

Field Guide for Inspecting Signalized Intersections to Reduce Red-Light Running

y Deficiency

onal signal head to achieve one signal per lane 

over each marked lane)

D signal head

inch signal head

uble red signal

kplates; larger or enhanced backplates

nsverse rumble strips

ng Operation Deficiency

ellow-change time (to correspond to ITE policy)

ge all-red clearance time

ate signal operation with adjacent signals

sures to Consider

dilemma-zone protection

ne if signal is still warranted

r roundabout or other innovative design

pavement condition

n of the final countermeasure(s) should be made

nsible engineer. The full report Making

Safer:A Toolbox of Engineering Countermeasures to

ight Running should be reviewed for this activity.
PART 3. CHECK SIGNAL CONTROL PARAMETERS

Grade (as decimal) g =_______(uphill is positive)

Approach speed V =____________mphCross street width W =____________feet

Calculate the needed change period (CP) for this approach using agency practice for the following equation:

PART 4. CHECK OTHER FACTORS

Is horizontal location adequate? Y N Enter the distance from the stop line to the first far side 

signal for the through movement.

Pavement condition on approach:

___Adequate ___Polished ___Severely Rutted

Should signal warranting study be conducted? Y N Other concerns:______________________________________________________________________________

21

Actual Value Calculated Value Is Existing

Adequate?

Yellow interval ____________ ____________ Y NAll-red interval ____________ ____________ Y N

Yellow All-red

CP = 1.0 + + __________ _____

1.47*V W +20 

 (20 + 64.4g) 1.47*V

{{

Field Guide for Inspecting Signalized Intersections to Reduce Red-Light Running

 2. CHECK SIGNAL CONSPICUITY

clutter detract from the signal? Y N 

al indications confusing? Y N 

:___________________________________

____________________________________

es present? Y N es necessary? Y N 

are-reducing steps needed? Y N 

pe: Incandescent LEDs

ize Adequate?:

al lens size: 8 inch 12 inch

e from stop line to signal: _______feet

e signal? Y N

ng size adequate? Y N

ignal Heads Adequate?:

mber of signal heads for major movement: _____

mber of lanes for major movement: __________

ng number adequate? Y N

 Placement Adequate?: Y N

for Inspecting Signalized Intersections to Reduce Red-Light Running
23

ENTIFY PROMISING COUNTERMEASURES

____________________________________

____________________________________

uld be completed for each intersection approach.

y: ___________________________________

_________

REFERENCES:1. Institute of Transportation Engineers/Federal HighwayAdministration. Making Intersections Safer:A Toolbox ofEngineering Countermeasures to Reduce Red-Light Running.Washington, DC: ITE, 2003.2. Federal Highway Administration. Manual on Uniform

Traffic Control Devices for Streets and Highways, Washington,DC: Federal Highway Administration, 2003.3. Institute of Transportation Engineers. Traffic Engineering

Handbook. Washington DC: Institute of TransportationEngineers, 1999.

 Deficiency

ditional signals

ide

ignal mounting

GNAL AHEAD

vance warning

relocate sight

on

ogrammable

elds and visors

Conspicuity Deficiency

___ Add signals to achieve

one per lane

___ Replace with LED lens

type

___ Replace with 12” signal

head

___ Install double red signal___ Install/enhance backplates___ Install rumble strips on

approach

___ Install near side signal

ng Operation 

ciency

ellow interval

ge all-red interOther Measures ___ Determine if signal is warranted ___ Consider roundabout or innovative design

___ Improve pavement

condition

for Inspecting Signalized Intersections to Reduce Red-Light Running
1099 14th Street, NW, Suite 300 West

Washington, DC 20005 USATelephone: +1 202-289-0222Fax: +1 202-289-7722ITE on the Web: www.ite.orgISBN 1-933452-04-8