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Evaluation of Devices to Prevent Construction Equipment 

Backing Incidents 

Todd M. Ruff 

Spokane Research Laboratory, National Institute for Occupational Safety and Health, 

Spokane, WA USA 

ABSTRACT 

Blind areas around construction equipment are a major 

contributing factor in incidents involving a piece of 

equipment striking a worker. In highway construction, 

these types of incidents result in an average of 22 deaths 

a year in the United States. The Spokane Research Laboratory of the National Institute for Occupational Safety and Health, in cooperation with the Washington State 

Department of Transportation, is evaluating methods to 

decrease these incidents. One such method uses devices 

that assist equipment operators in monitoring blind areas 

around the equipment to prevent collisions with workers 

or other objects. Several camera and sensor systems are 

available for this application. These systems were evaluated on various trucks used in road construction and 

maintenance. Tests were conducted on sanding trucks 

during the winter months, which allowed researchers to 

investigate the effectiveness and limitations of various 

technologies under the most extreme conditions. Tests 

were also conducted on dump trucks and utility vehicles 

during the warmer months to study the effectiveness of 

the systems in highway work zones. Results showed that 

many difficulties arise when using camera and sensor 

systems in cold, snowy climates. And, while the operation of these systems is more reliable during the warmer 

months, challenges still exist in using them on equipment in congested work areas. 

INTRODUCTION 

The Spokane Research Laboratory of the National 

Institute for Occupational Safety and Health (NIOSH) is 

cooperating with the Washington State Department of 

Transportation (WSDOT) in an evaluation of technologies that assist drivers in monitoring blind areas around 

construction equipment. One such technology consists of 

cameras that provide a view of the blind area; another 

features sensor-based collision warning systems that 

warn the driver if an object or person is nearby. 

Road construction workers must work very close to 

moving equipment. According to Pratt et al. (2001), the 

majority of fatalities that occur in highway construction 

work zones in the United States involve a worker being 

struck by construction equipment or another type of 

vehicle. In fact, a worker in the construction industry is 

just as likely to be struck by a piece of construction 

equipment inside the work zone as by passing traffic. 

Also, half the fatalities involving construction equipment 

occur while the equipment is backing. Accidents involving WSDOT equipment often involve some type of truck 

backing into a worker or another vehicle. This and the 

blind areas associated with construction equipment contribute to making road construction a dangerous occupation. 

For this reason, a study was initiated to evaluate methods 

of monitoring blind areas around trucks used in road 

construction and maintenance. Several camera and sensor systems are available for this application, and understanding the difficulties in implementing these systems 

on trucks used in all types of weather is important. Tests 

were conducted on sanding trucks and utility vehicles 

during the winter months, which allowed researchers to 

investigate the effectiveness and limitations of various 

technologies under the most extreme conditions. Other 

tests were conducted on dump trucks and utility vehicles 

during the warmer months to study the effectiveness of 

the systems in highway work zones. 

NIOSH researchers’ experience with camera systems 

and collision warning systems on mining equipment 

helped narrow the list of technologies to be evaluated 

(Ruff, 2001). Systems were selected on the basis of their 

ability to sense obstacles through snow and rain, to 
handle the tough environment of highway construction,

and to meet minimum standards regarding mounting 

position and detection range. All systems went through 

an initial test to determine if they could be mounted on a 

particular piece of equipment and function according to 

minimum specifications. These included—

• Low probability of a false alarm in a clear, flat area

(parking lot).

• Reliable detection of a person in a zone starting

immediately behind the truck, extending at least 2.7 

m (9 ft) behind the truck, and covering the width of

the truck. 

• Apparent ability of the system to handle harsh conditions. 

• Ease of mounting and configuring a system on a 

vehicle. 

For more details on these tests, see Ruff (2003). If a 

system operated satisfactorily in initial tests, then tests 

were conducted for several months while the equipment 

was used in actual road construction and maintenance 

activities. 

TEST PROCEDURE 

The following systems were chosen for long-term tests 

on WSDOT dump trucks, utility vehicles, and plowing 

trucks: Preco’s Standard Preview radar system, Sonar

Safety System’s Hindsight 20/20 sonar system, and Intec 

Video System’s Car Vision camera system. Other 

systems were also evaluated in an earlier phase of testing 

as described in Ruff (2003), but the most thorough 

evaluations were conducted on these three systems. 

Systems selected for long-term tests were permanently

mounted on a WSDOT truck according to the manufacturer’s suggestions. In some instances, the mounting 

position of the system had to be changed due to the particular configuration of the truck. Long-term tests in the 

winter were conducted on a tandem-axle sanding/plowing truck (figure 1A) and a sport utility vehicle (figure 

1B). Long-term tests during warmer months were conducted on a 7.6-m3

 (10-yd3) dump truck (figure 1C), the 

sport utility vehicle, and a pickup truck (figure 1D). Test

duration was 2 months or more in actual work situations. 

Jobs during the summer months usually involved asphalt 

patching operations or road material hauling. Jobs during 

winter involved sanding and plowing operations. 

To evaluate the systems, a form was available in the cab

of the truck so the driver could make daily comments 

and record the effectiveness of the system. Informal 

discussions with drivers and direct observation of the 

system in use also helped researchers understand a

system’s problems and capabilities. In one set of tests, a 

data collection system that recorded video from a camera

along with Preview radar alarm information was used to 

Figure 1.—WSDOT test vehicles. A, Sanding/plowing truck; B, sport utility vehicle; C, dump truck; D, pickup truck. 

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determine the source of alarms and distinguish false 

from real alarm rates. When the long-term test was 

completed, the systems were removed from the trucks 

and inspected for damage or abnormal wear. 

TEST RESULTS 

SYSTEM 1: 

Standard Preview radar system, model SPV2015 

Manufacturer: Preco Electronics, Boise, ID. 

Approximate cost: $350 

System Description: This radar system uses pulsed

microwave signal techniques to detect an object in the

radar beam. It consists of a radar antenna and processing 

electronics, an alarm display, and cables (figure 2). No 

motion of the object or vehicle is needed for detection.

The alarm display indicates distance in 1-m increments

using a series of LED’s. An audible alarm that changes 

in frequency as the distance to an object changes is

generated. The radar system is designed to monitor the 

rear blind area and is activated when the vehicle is in 

reverse. This model has no user-adjustable settings. 

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Figure 2.—Preco's Preview radar system 

Figure 3.—Preview radar antenna mounted on hitch plate. 

Test Results-Dump Truck: Tests were conducted on a 

tandem-axle dump truck (figure 1C). Several positions 

for the radar antenna were tried; the best results were 

obtained when the antenna was mounted on the hitch 

plate at a height of 89 cm (35 in) and slightly off-center 

(figure 3). The antenna could not be mounted closer to 

the center of the truck because the system may detect the 

hitch, causing false alarms, or be crushed when the truck 

is backed up to a trailer tongue. The alarm display was 

mounted on top of the dashboard in the cab. 

The solid line in figure 4 shows the detection area for a 

person standing behind the truck. The zone was verified 

by moving the truck slowly in reverse toward a person,

with no significant differences. This detection zone was

adequate and extended to 4.6 m (15 ft). The dashed line

shows the detection area for the same person in a 

crouching position (on one knee and bent at the waist). 

The detection zone for a crouching person was smaller in 

width than for a standing person. This caused some

concern because of the potential for someone to be

crouching and working behind the truck. 

The radar system was tested through the spring on this 

truck. Several discussions with drivers indicated that the 

radar system was well accepted. The radar produced few

false alarms and operated reliably, even with a few

millimeters of mud caked on some places on the 

antenna. Drivers stated that the radar alarms prompted

them to reverse with caution and recheck mirrors. They 

did comment that nuisance alarms from nearby

equipment or berms were frequent in congested work 

areas. Nuisance alarms are caused from objects which 

the operator is already aware of, e.g., a piece of 

equipment, or objects that pose no danger, e.g., foliage. 

While anecdotal data such as driver comments are useful 

in determining if a system is effective and accepted by 

users, researchers wanted to obtain quantitative data 

also. For example, it is difficult to quantify false alarms

without having some knowledge of exactly what is 

behind the vehicle when they occur. Many times the 

system is correctly detecting a pot hole, a rock, or some

other object that the driver does not consider a hazard.

For this reason, a video recorder that accepted sensor 

inputs was used to record time-stamped video from a 

rear-mounted camera, along with radar alarms. (More 

discussion on the camera system can be found later in 

this report.) In some of the tests, the camera view was

also made available to the driver on a video monitor in 

the cab. Consequently, many of the driver comments

concerned the combination of radar and camera systems.

The main conclusion drawn from the feedback was that 

the radar system was very useful in prompting operators 

to look at the video monitor when an alarm sounded. 
The camera also allowed the driver to check

the source of any alarms, which greatly reduced the inconvenience of getting out of the 

cab to verify whether the area was clear. The

combination of the two systems offered many

advantages over using either system by itself. 

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Figure 5 shows an example of a video obtained from the camera and radar combination. 

Note that a “W” appears on screen whenever

the radar system alarms. Since the radar detection zone is entirely contained within the 

camera’s field of view (FOV), any object that

causes an alarm can be seen in the video. 

This allows researchers to determine when

alarms occur and what causes them. In this

case, the radar system correctly detected the 

nearby equipment and workers. 

The first video was collected during a sand 

hauling operation, and 6 hours of footage was 

recorded to tape. Very little backing occurred 

during this work. Only one radar alarm was 

recorded, and the video showed that the walls

of the maintenance shop were correctly 

detected as the truck backed out of the shop. 

The truck did back up to a dump point four

times in the video footage; however, a wheeled loader 

had pushed the sand over the edge after each dump, and 

the small sand pile remaining was not detected by the 

radar. 

The next video was collected during an asphalt paving 

operation, and another 6 hours of footage was collected. 

In this footage, eight backing events and four radar 

alarms were generated during these events. Two of the 

alarms correctly warned of nearby objects or workers. 

The other two alarms were from the detection of tall 

weeds behind the truck. There were no instances where

the radar missed detecting an object or person. At the 

time of writing this report, more video footage was being 

collected so more meaningful conclusions could be

drawn. 

Figure 4.—Detection zone for a person and Preview radar system on dump

truck.

Test Results-Sanding/Plow Truck: Tests of the radar 

system through the winter were conducted on a sanding 

truck (figure 1A) to determine the system’s effectiveness 

in harsh weather conditions. Radar mounting was the

same as described above for the dump truck. Only driver 

interviews and a researcher’s direct observation were

used to obtain feedback on the system’s operation. 

Driver comments were generally favorable for wintertime use of the radar. The build-up of snow and ice on

the back of these trucks can be extensive during snowy 

conditions, and this was a major concern (Ruff, 2003).

However, the driver of the truck did not complain of any 

false alarms and indicated that snow was not sticking to 

the radar antenna. Road grime did build up on the 

antenna, but did not cause alarms. The truck was sprayed 

with water at the end of each shift, and this may have 

prevented a significant amount of grime or snow from 

Figure 5.—Screen shot of video from rear camera view. 

Note that the “W” indicates a radar alarm. 
building up and causing false alarms. The driver did

state that the radar system prompted him to recheck 

mirrors and reverse with extra caution. 

Midway through the winter, the radar system malfunctioned. The cause was determined to be corrosion of the

wires that provided power to the sensor system. Power 

for the radar used the same reverse signal that powered

the backup alarm. Open lug terminals on the backup

alarm corroded from the de-icing solution applied on the 

road by the truck. This is a common problem with any

exposed wiring on these trucks. The terminals were

cleaned and the wiring was re-terminated, which fixed 

the problem. 

SYSTEM 2:

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Intec camera system

Distributor: Intec, Laguna Hills, CA 

Approximate cost: $1100 

System Description: The Intec camera system consists

of a small camera the size of a 5-cm (2-in) cube (model 

CVC210XL), an 11.4-cm (4.5-in) video monitor (model 

CVM450LPP), and cables (figure 6). 

Test Results-Dump Truck: Initially the camera was 

mounted on the right side of the dump box, above the 

rear taillights that are integrated into the box (figure 7). 

Tests showed that this was an acceptable mounting 

position and provided an acceptable FOV for the driver. 

However, a crouching person near the back of the truck

might not be in view because of the camera’s high 

position. It might also be of more benefit to mount the 

camera on the left side of the box, pointing to the right, 

so that the larger blind spot to the right would be 

covered more adequately. 

Because the dump box is removed and replaced with a 

sand hopper, WSDOT and NIOSH researchers wanted to

find a mounting position that would be undisturbed 

during the box switching process. An alternative camera

mounting position near the hitch is shown in figure 8. 

This may not be an adequate position for all truck types, 

especially if the camera is in the path of material as it

flows out of the tailgate or if the FOV is blocked by

structures on the truck. The monitor was mounted in the 

cab on the center pedestal between the seats. This 

allowed the driver to check the monitor without too 

much head movement after checking the right side 

mirror. Other monitor positions are acceptable, and 

feedback from the driver is required to find the preferred 

position. Figure 9 shows the FOV of the camera with the

view extending to the horizon. 

Figure 6.—Intec camera system

Figure 8.—Intec camera mounted near hitch.

The camera system was tested during spring and summer

months with positive comments from the drivers. The

camera has the advantage of providing an actual view of 

the blind area, and drivers relied on it to help them posiFigure 7.—Initial mounting position for Intec camera on

dump box. 
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Figure 9.—Field of view for camera mounted near hitch. (Note: 

dimensions are in meters.) 

tion the truck and check for obstacles. Some debris built 

up on the camera lens, especially in wet weather. This 

usually did not significantly obstruct the camera view, 

and cleaning the lens at the end of each shift was sufficient. At the end of the test, the camera, monitor, and 

cables were inspected, and no unusual wear or corrosion 

were seen. 

One disadvantage to camera systems is that they do not 

provide an alarm if an obstacle is present. If the driver 

forgets to check the monitor before backing the truck, a 

potential collision may go unnoticed. For this reason, 

tests were later conducted with the Preco radar system 

and camera on the same truck as mentioned in the 

previous section. Driver comments indicated that the

combination of systems was more effective than either 

system by itself. However, if only one system could be

used, the camera system was preferred over radar

because of numerous radar alarms in congested work 

areas. 

Test Results-Sanding/Plow Truck: In the fall, the dump

box on this truck was replaced with a sand hopper, and a 

snow plow was mounted to the front. Because the 

camera and cabling were mounted on the chassis, they 

remained in the same position as in the dump truck tests. 

Tests of the camera system during the winter showed 

that the camera view was quickly obscured by snow or

road grime after traveling just a few miles down the 

road. Earlier tests showed that this was true for higher 

camera mounting positions also. For this reason, a lens 

washing system was devised by Intec, Inc., and sent to 

NIOSH for testing. The prototype system consisted of a 

nozzle that mounted just above the camera that allowed

the driver to blast compressed air and washing fluid on 

the camera lens (figure 10). NIOSH researchers were

only able to test the washing system on road grime

build-up and it worked well. However, tests need to be 

conducted for snow and ice build-up. During cold and 

snowy conditions, several centimeters of snow and ice 

can accumulate on the back of the truck, and it was not

determined if the washing system would work in these

conditions. More tests are planned. 

Figure 10.—Prototype lens cleaning system.

During the winter tests, one camera failure was experienced. A short circuit occurred in the internal components of the camera head and was repaired by Intec. Cable

connections were somewhat corroded due to the de-icing 

chemicals and salt used on the roadways. The corrosion 

was slight and did not cause any system malfunctions

during the course of the tests. 

SYSTEM 3:

Hindsight 20/20 ultrasonic sensor system, model HS300 

Distributor: Sonar Safety Systems, Santa Fe Springs, 

CA 

Approximate cost: $400 

System Description: This sonar-based system works by

transmitting high-frequency sound waves and detecting 

reflections of these waves from objects within the sound 

beam. The maximum range of this system was specified 

as 2.7 m (9 ft). It consisted of two sensors with rubber 

enclosures, an alarm display with LED's and an audible 

alarm that changes frequency depending on distance to 

the detected object, a cable junction box, and cables 

(figure 11). 

Test Results-Dump Truck After some experimentation

to find a suitable mounting position, the sensors were 

placed near the taillights on the hitch plate, as shown in 

figure 12. The sensors were mounted at a height of 76 

cm (30 in) with 81 cm (32 in) spacing. Spacing greater 
Figure 11.—Hindsight sonar system (two sensors).

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Figure 12.—Hindsight system sensors mounted on dump truck. 

than this, e.g., on the lower corners of the dump box, 

resulted in missed detection of a person near the truck 

between the two sensors. Furthermore, it was desired to 

mount the sensors in a location that would not be 

disturbed by the replacement of the dump box with a 

sand hopper in the winter. The alarm was mounted on

the driver’s side of the dashboard. The detection zones 

for a standing and crouching person are shown in figure 

13; this system had a detection range of 2.4 m (8 ft). 

The system was tested during the summer months on 

road-patching and material-hauling jobs. No evaluation 

forms were turned in, but comments from drivers were

received through interviews and are summarized below. 

• The system was reliable, and false alarms were rare

in most situations. 

Figure 13.—Detection zone for Hindsight system on dump

truck. 

• The system produced false alarms when backing 

through thick airborne dust.

• The system alarmed continuously when a trailer was 

pulled behind the truck, and there was no way to

turn the system off temporarily (without disconnecting it). 

Modifications will be needed for this system to function 

on trucks that pull trailers. This is true for all sensorbased systems that do not require object motion for an 

alarm. Sonar Safety Systems sells an add-on to the 

system that detects when a trailer is present by sensing 

when the trailer light connector is plugged into the truck. 

If the trailer lights are connected, then the system disables the truck-mounted sensors and switches to sensors 

on the trailer. This was not tested, but would be an

acceptable solution. 

Sensing dust was a problem with this sonar system

according to the drivers, which brought up concerns 

about false alarms in snow and rain. Drivers did not

notice false alarms in rain. The manufacturer did acknowledge the possibility of false alarms in heavy snow. 

Additional tests are needed to determine what precipitation rates would cause an alarm, if any.

Concerns were also raised regarding the short detection 

range of the system. A person immediately behind a very

slow-moving truck might be detected in time for the 

driver to react. However, in fast-moving situations, 2.4 

m (8 ft) of detection does not give adequate time to 

respond (Society of Automotive Engineers, 1999). 

At the end of the summer, the system was removed and 

inspected. All components were in good working order. 
Test Results-Sanding/Plow Truck In the winter following the summer tests, the dump box was removed from 

the truck chassis and replaced with a sand hopper. A 

snow plow was also attached to the front of the truck. In 

this new configuration, mud flaps attached to the sand

hopper platform hung down near the sonar sensors. The 

flaps caused false alarms on the sonar system. An alternative mounting configuration was not found that would

allow the sensors to remain on the hitch plate, so tests 

were not conducted during the winter months with this 

system. An alternative mounting site could have been 

possible, but probably would have required the sensors 

to be mounted on the sand hopper platform. This was not 

desired because of the sand hopper is removed seasonally and subsequent reinstallation of the sensors and 

wiring on the dump truck would be timeconsuming. 

Test Results-Utility Vehicles: Tests on two utility vehicles were conducted with the sonar system. These types 

of vehicles are involved in a high percentage of the 

backing incidents experienced by WSDOT. A Ford 

Explorer and a pickup with a large walk-in box were 

chosen for these tests, which had been in progress for 7 

months at the time of writing this report.

A single sensor system (HS100) was mounted on the 

receiver hitch of the Ford Explorer (figure 1B) at a 

height of 50 cm (20 in) at the center of the vehicle. The 

alarm display was mounted in the rear cargo area of the 

cabin and near the upper right corner of the rear window. 

This was the recommended mounting position and 

allowed the driver to see the warning lights when 

looking over the right shoulder while reversing. Power 

for the system was taken from the reverse lights. The 

detection area for a person covered the width of the 

vehicle and extended to 2 m (6.6 ft) from the bumper in

a rectangular shape. 

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Comment forms were received from the driver, and 

periodic interviews were conducted. Early in the tests, 

the system did occasionally generate false alarms from

detecting the ground, and consistent alarms when backing to a concrete curb approximately 13 cm (5 in) high.

To reduce these alarms, the sensor mounting bracket was 

adjusted so the sensor had an upward angle of 5 degrees.

This modification eliminated false alarms and most curb 

alarms. There is a tradeoff to angling the sensor upward 

any further because this can cause the system to miss

rocks or other objects that need to be avoided. 

During the warmer months, the driver stated that the 

system worked reliably. False alarms were rare. Weeds

or tall grass behind the truck did cause alarms, but the

driver did not feel this was too much of a nuisance. He

stated the system warned him of nearby vehicles several 

times, which caused him to be more cautious when

reversing. The main concern for this driver was that the 

detection zone was too small to provide adequate warning when reversing at higher speeds or when turning and 

reversing at the same time. During the winter months, 

the driver did not see any reduction in sensor performance. He was careful to remove any snow built up on the 

sensor before driving the vehicle. It is important to note 

that the driver requested that the system be left on the 

vehicle after the tests were completed. 

On the pickup truck (figure 1D), a two-sensor system

was tested (HS300). This vehicle was wider than the

Ford Explorer and required two sensors for adequate 

detection. The sensors were mounted near the ends of 

the rear bumper at a height of 46 cm (18 in) and a 

spacing of 1 m (39 in), as shown in figure 14. The alarm 

display was mounted in the cab on the dashboard. The 

sensor configuration resulted in a detection area for a

person that was similar to that in figure 13. It covered

the width of the truck and extended 2.5 m (8.2 ft). Early 

in the tests the system generated false alarms when the

truck was moved in reverse in a clear area on asphalt or 

gravel surfaces. The sensor mounting brackets were

modified so the sensors had an upward angle of

approximately 5 degrees. This eliminated false alarms on 

flat ground, but still allowed a 13 cm (5 in) high curb to 

be detected. 

Figure 14.—Hindsight system sensors mounted on pickup.

The system was tested through the spring and summer, 

and driver comments were obtained through periodic

interviews. The driver stated that false alarms were very 

rare, but nuisance alarms were common. Nuisance

alarms were especially frequent on road construction job 

sites where barriers, cones, and other equipment were

commonly near the truck. The driver stated that the 

nuisance alarms affected his ability to trust the system.

The driver did appreciate that the system could warn 
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when a person entered the rear blind spot of the truck, 

but he stated that this situation was rare and was not 

experienced during the tests. 

This truck was not used during winter months, so no 

feedback was received for winter use. The driver requested that the system be removed after the testing was 

completed.

CONCLUSIONS 

While many more collision warning and cameras 

systems are available than were tested here, tests of the 

above systems did show the challenges associated with 

implementing these types of systems on trucks used in 

the winter or in congested highway work zones. The 

following general observations can be made based on 

these test results.

• Highway construction zones are typically crowded 

with equipment and workers on foot. Sensor-based 

collision warning systems, e.g., radar or sonar, will 

alarm often in this environment. These alarms will 

most often be nuisance alarms caused by workers or 

objects of which the driver is already aware or that 

are not in danger of being hit. If too many alarms are 

associated with objects that are not in real danger, all 

alarms will eventually be ignored. For this reason, 

camera systems may be more appropriate in this 

environment. 

• The alarm functions of sensor-based systems provide 

a warning to the driver and are a more positive 

method of monitoring, while camera systems are a 

more passive technology, much like mirrors. Using 

the two systems in combination on the same truck 

may have many advantages. The camera system 

provides an actual view of the blind area near the 

truck and provides a method to check the source of 

any alarms. At the same time, the sensor provides an 

alarm that prompts the driver to check the video 

monitor so that the potential for a collision does not 

go unnoticed. There would still be a problem with 

frequent nuisance alarms in highway work zones, 

but they may be more tolerable if there is a quick 

method of checking the source of any alarm. 

• If sensor-based systems are implemented on a 

vehicle, some method must be used to eliminate 

false alarms from mud, dirt, or snow build-up on the 

sensing portion of the system. This can be done using processing methods that ignore object detection 

directly in front of the sensor or by using some other 

means that prevents debris from blocking the 

sensor’s signal. 

• Most trucks used in construction are also used to 

pull trailers. Most sensor-based collision warning 

systems will sense the trailer and produce an alarm. 

Some method must be provided to disable the 

system when a trailer is being pulled or allow quick 

connection to separate sensors mounted on the 

trailer. 

• Cameras work well during warmer months, and 

daily cleaning of the lens is usually sufficient. However, on some types of equipment, snow and grime 

build up on the lens quickly during winter months. 

Some method of preventing snow, ice, and grime 

from covering the camera must be employed. 

• It is often difficult to find a mounting position for 

sensors or cameras, especially on dump trucks. 

Mounting these devices on the side of the dump box 

was found to be an acceptable solution if the size of 

the device will allow this. If the dump box is removed seasonally, it may be desirable to mount the 

sensor or camera in a position where it will not need 

to be remounted and the wiring rerouted. Mounting 

near the bumper/hitch area is acceptable, but the 

increased exposure may shorten the sensor or 

camera’s life and may cause the camera lens to be 

obscured more quickly. 

• Many camera and sensor systems are available for 

automobiles and on-road trucking. The construction 

equipment application is more demanding and harsher than standard transportation applications. It is 

important to choose systems made for and proven on 

heavy construction equipment. 

ACKNOWLEDGMENTS 

The author would like to thank Rich Rains of NIOSH for 

his assistance in the installation of the various systems 

on the trucks. Also, Loran Dantzler, David Henderson, 

and the equipment operators at WSDOT were extremely 

helpful and instrumental in conducting tests and providing feedback on the operation of the systems. 

REFERENCES 

Pratt, S.G., D.E. Fosbroke, and S.M. Marsh. (2001). 

Building Safer Highway Work Zones: Measures to 

Prevent Worker Injuries From Vehicles and Equipment. 

DHHS (NIOSH) Publication No. 2001-128, 71 pp. 
10

Ruff, Todd M. (2001). Monitoring Blind Spots–A Major 

Concern for Haul Trucks. Engineering and Mining 

Journal 202(12), 17-26. 

Ruff, Todd M. (2003). Evaluation of Systems to Monitor 

Blind Areas Behind Trucks Used in Road Construction 

and Maintenance: Phase 1. DHHS (NIOSH) Publication 

No. 2003-113 (NIOSH Report of Investigations 9660) 

15 pp. 

Society for Automotive Engineers [SAE]. (1999). 

Discriminating Back-Up Alarm System Standard. 

Surface Vehicle Standard - J1741.