Work Zone Operational Enhancements

Integrating ITS into a Design BUild project

**Arizona State Route-68**

By Alan Hansen

FHWA Arizona Division

Supported by: Debra Brisk and Jennifer Livingston

Arizona Department of Transportation

State Route 68 (SR-68) is located in northwest Arizona and runs between
Kingman and Bullhead City. The SR-68 project starts at about the mid-way
point of SR-68 and extends to Bullhead City. The SR-68 project is a \$42
million project covering 13.5 miles. The scope of the project is to
reconstruct the existing 2-lane highway into a 4-lane divided facility.
This is a very rural corridor cutting through both high desert landscape
as well as the Black Mountains. Although this is a rural corridor, this
route is considered a major commuter route for people traveling between
Kingman, Bullhead City, and Laughlin, Nevada. In addition to the
commuter traffic there are also 6% trucks and significant recreational
users that travel the corridor. SR-68 serves as the alternate route for
the Hoover Dam. With the Hoover Dam being closed to truck traffic since
September 11^th^, 2001 this route is even more critical. The Arizona
Department of Transportation (ADOT) wanted to minimize the delay to all
the motorists on a day-to-day basis. This has resulted in two unique
features on this design/build project. The first is a motorist assist
patrol and the second is a travel-time system incentive program. Both of
these programs were brought about by the efforts of the ADOT's Kingman
District Engineer -- Debra Brisk. This report documents a site visit
taken with the ADOT Resident Engineer -- Jennifer Livingston and
provides the status of these operational enhancements with the project
approximately 35% complete. The project has a revised completion date of
Spring 2002.

# Motorist Assist Patrol

The purpose of the motorist assist patrol (MAP) is to keep the roadway
clear, identify incidents and maintain smooth operations. The contractor
operates the MAP from 4pm to 6am on weekdays and around the clock on
weekends and holidays. The contractor hired a private security guard
service to operate the MAP vehicles. While the drivers of the MAP
vehicles are trained as security guards, they dress in typical
construction type clothing including hard hats and vests. Based upon
discussions with the ADOT Resident Engineer, the contractor felt that
hiring trained security guards would make it a safer environment for the
MAP drivers.

The MAP is equipped with traffic control devices, water, gasoline,
flares and lighted arrow boards. The MAP had assisted 945 stranded
motorists in the corridor through February 2002. The majority of the
travelers were stranded due to mechanical failure, 641 of these were
able to get back on the road just with the assistance of the MAP. The
MAP also assisted an additional 230 motorist to get outside assistance
such as towing or a service truck. It is generally believed that the
mechanical failures experienced in the corridor are related to the high
temperatures and the 6% grade through much of the project.

# Travel-Time System Incentive Program

The State Route 68 Design/Build project has also implemented a Travel
Time System that measures speed consistency and performance through the
construction work zone. The length of the SR-68 project is approximately
13.5 miles. Prior to construction, the average travel time for this
segment, which has a posted speed limit of 55 MPH, was 17 minutes.
During construction, traffic control measures, and reduced posted speed
limits of 35-45 MPH have increased the corridor travel time to
approximately 21 minutes. The contract for the project included a
provision that during construction the travel time could not exceed an
average of 27 minutes. The contract provided for a \$400,000 travel time
budget item that would be drawn against if the target travel time
average was exceeded. The incentive of this provision was that at the
end of the project any funds still in the travel time budget would be
profit for the contractor. Should the contractor not be able to maintain
the target travel time during construction, it is possible for the
entire funds in the travel time item to be used and the item would then
turn into a disincentive where the contractor would be responsible for
paying for the added delay.

The contractor was also responsible for determining the best way for
measuring the travel time through the project. The contractor chose to
deploy a license plate reader system developed by the British company
Computer Recognition Systems, which has a United States headquarters in
Boston. This system uses a camera and a light source to capture license
plate images of passing vehicles. The license plate number is taken from
the picture by image recognition software, encrypted, then sent to the
central computer at the contractor's office through a high-speed data
connection. The system is optimally designed to capture license plate
readings at 45 to 55 MPH. There is a second camera at the end of the
project, which takes a second picture, encrypts that license plate
number and sends it to the central computer. The central computer then
attempts to match up license plates that enter and exit the limits of
the construction project. There are cameras at the entrance and exit of
the project in both directions providing for a total of four cameras on
the project. Other technologies considered for the travel time system
included radar systems that would be deployed throughout the corridor
and give single point traffic speeds but would not offer direct
measurement of corridor travel times.

The cameras have been mounted behind construction signs to keep from
distracting the motorist. Each of the four locations includes a camera
on one sign assembly and a light on a second sign assembly. The light
and camera are then positioned to capture license plate readings on
passing vehicles. The license plate readings are encrypted and
continuously sent back to the contractor's central computer on a
high-speed data connection. None of the license plates numbers are
recoverable after the encryption process to honor the privacy of the
motorist. The light is needed to assist in reading the license plates,
including being able to read through the plastic covers that are
installed over the license plate by some motorists. The system operates
24 hours a day. The general lay out of the cameras and light are shown
in the following pictures. The first picture shows the signs that the
camera and light are mounted behind and the second picture shows the
actual equipment.

To date the contractor has experienced very few times when the average
travel time goal has not been met. This has resulted in only about
\$2,000 being drawn out of the travel time item. The license plate
reader system is able to match around 11% of license plates between the
start and finish of the project. The license plate match rate is
influenced by the system reading only one lane of traffic yet there are
two lanes of traffic at the location of both the license plate readers.
This rate is considered good compared to other license plate reading
projects around the world and is adequate for the average travel time
estimates used on this project.

The license plate reader system has experienced some issues. Early in
the project there were some complaints that the light was distracting to
motorists traveling in the opposite direction of the camera/light
placement. These complaints were resolved by better light placement, the
motorist becoming accustomed to the lights being there and public
outreach and education. These lights are not as bright as regular
construction zone lighting. One of the cameras was also stolen. This has
resulted in the contractor welding the cameras to the sign structure and
installing a chain locking system. As the construction proceeds and
travel lanes are moved, the cameras and lights must be adjusted so the
license plates of the cars are still clearly in the field of view. Some
privacy concerns were raised at the start of the project, however the
central computer does not maintain any of the license plate numbers
after they have gone through the initial encryption process. This has
eased the privacy concerns. The license plate reader system is also
fairly expensive to operate. The system requires high-speed data
connections, which cost about \$700/month for a T1 line and about
\$200/month for a wireless connection. There is also a monthly
electricity cost of approximately \$100/month. At the end of the project
the license plate reader system will be the property of the contractor.

# SUMMARY

Both of these programs have helped to make the State Route 68 project a
model for innovative work zone features. The motorist assist patrol has
helped many stranded motorists. ADOT has provided comment cards to the
motorist who have been helped by the patrols and have received a survey
return rate of nearly 50 %, all of which have made positive comments
about the patrols. Clearly this program is very popular with the
traveling public. The travel time incentive program is not as visible to
the traveling public but they are still enjoying the benefits. Due to
this program, the contractor has made great efforts to limit the delay
to people traveling the corridor. The contractor has made sure to limit
the number of flagging stations throughout the project and has scheduled
work in such a way that it reduces the impacts to the public. ADOT has
made extensive efforts to communicate with the public regarding this
project. Their public outreach efforts have included public service
announcements, cable television announcements, a speakers bureau, radio
media alerts and an established website
([www.highway68construction.com](http://www.highway68construction.com/)).
These forums have allowed for public input into how the project is
perceived by the motorists who use the corridor and the general findings
are the public feels that the construction work zone has not
significantly affected travel through the corridor. Work Zone programs
such as these help to limit the delay to the public, improve
transportation system efficiency, increase work zone safety and provide
a better working relationship between the State DOT, contractor and the
community.